Algae & Sanjeet

Phycology has made great advances in the twenty first century.  Though the use of algae as food is very old as even mentioned “in the poetic literature of the Chinese, about 600 B.C.”, they are still considered less economically important than fungi and bacteria.

Phycologists in different parts of the world, besides investigating morphological, cytological, physiological and other details of algae, are also exploring continuously the beneficial aspects of these tiny, adventurous and wonderful plants of the beautiful nature. Though many workers are trying to find out the food value of algae, their importance in industries and their uses and disuse in many other ways have not been overlooked. The importance of the roles played by algae in the world is becoming more appreciated each day because of the increased realization that many of them are extremely valuable to man.

Except for the chemosynthetic bacteria, all organisms are directly or indirectly benefited from algae. Exploration of the seas, which are full of algae, has brought home to man the usefulness of algal flora.  The algae are useful as the source of many commercial products such as agar-agar, carrageeain, alginic acid diatomic funorin, kelp etc.

Status of Biodiversity & Sanjeet

Sanjeet Kumar

Ravenshaw University

sanjeet.biotech@gmail.com

Biological diversity is the variety and variability among living organisms and the ecological complexes in which they occur and encompasses species diversity, genetic diversity and ecosystem diversity. Scientifically 1.4 million species of living organisms have been enlisted so far. Of these, there are 360,000 microbes, 300,000 flowering plants, 800, 000 insects and 40, 000 vertebrates. However, it is believed that the actual number of species may be between 10-80 million. Rich and diverse forms of plant, animal and microbial life inhabits warm and humid regions in between the Tropic of Cancer and Capricon. Countries like Brazil, Columbia, Mexico, Peru, Ecuador, Indonesia, Malaysia, India, Zaire, Madagascar, Australia that are located in this region are known as mega diversity countries. Areas where high levels of species richness, threat and endemism coincide are termed hot-spots. In India we find high level of biodiversity, 48,000 plants reported so far represents 11 % of world flora while 80, 000 species of animals represents 6.4 % of world fauna. Biodiversity is important as it provides natural resources, genetic resources maintain stable ecosystem, ensure optimum utilization and conservation of a biotic resources. It is quite alarming that this enriched biodiversity on earth on which life is totally dependent is under threat of rapid loss. Various caused for the loss of biodiversity are the destruction of habitat, hunting, exploitation of selected species, habitat fragmentation, introduction of exotic species, pollution and natural calamities. To preserve these diverse biological species conservation measure have been undertaken. Either the biodiversity is conserved in its natural habitat (in situ conservation).

India is very rich in all aspects of biodiversity and is one of the most significant biodiversity centres of the world. Varying physiographic and climatic conditions at different parts of India are the reasons for this high level of biodiversity. India, with a geographical area of 329 million hectare has almost all kinds of ecological zones found in the world. India is the meeting ground for three major global bio- geographic regions.

1.    Indo-Malayan

2.    Eurasian

3.    Afro-tropical

It has two of the 34 recognized biodiversity “Hotspots” in the world- The Himalaya and the Western Ghats.

48,000 species of plants which represents 11 % of the total world flora and 80,000 species of animals representing 6.4 % of the world’s fauna are found in India. India’s floral diversity includes 17,500 species of angiosperms, over 64 species of Gymnosperms, 1,022 species of Pteridophytes, 2,843 of Bryophytes, 1,600 species of lichens, 23,000 species of Fungi and 2,500 species of Algae. Similarly, the faunal diversity of India includes 5,000 species of molluscs, 60,000 species of mammals. According to an estimate 35 % of the flowering plants and 18 % of the total flora are endemic to India. The endemism among the animals is high and it may be as high as 62 % in case of Amphibians. Many of the biologically rich areas in India are either unexplored or underexplored. The present knowledge regarding the diversity of microorganisms, wetland flora and fauna and marine life is scanty. It will be quite relevant to mention here that the Indian sub-continent is one of the 12 centres of origin and diversity of crop plants. It has given to the world nearly 167 species of crop plants. The following crops arose in India and spread throughout the world: rice, sugarcane, jute, mango, citrus, banana, several millets, spices, medicinal, aromatics and ornamentals. The rich germplasm reserve of Indian sub-continent includes 51 species of cereals and millets, 104 species of fruits, 27 species of spices and condiments,  55 species of vegetables and pulses, 24 species of fibre crops, 12 species of oilseeds and various strains of wild tea, tobacco and sugarcane. Besides above , 1,000 species of plants are of ethnobotanical interest and 2,000 species are used in various traditional system of medicine. India’s indigenous livestock diversity includes about 27 breeds of catties, 40 breeds of sheep, 22 of goats, 8 of camels, 6 of horses, 2 of donkeys and 18 types of poultry. Eight indiginious breeds of buffalo in India represent the entire range of genetic diversity on the earth. These prized plants and animals together with their ancestral wild forms are used by plant and animal breeders for the development of improved varieties.

Biodiversity can be measured in different ways. Two main factors taken into account when measuring diversity are richness and evenness. Species richness is the number of different species present in an area. However , diversity depends not only on richness but also on evenness. Evenness compares the similarity of the population size of each of the species present. Evenness is a measure of the relative abundance of the different species making up the richness of an area.

India occupies only 2.4 percent of the world’s land area but its contribution to the world’s biodiversity is approximately 8 % of the total number of species, which is estimated to be 1.75 million. Based on the available data, India ranks 10^th in the world. The ten important biogeographically zones having rich biodiversity are:

1.    Trans-Himalayas

2.    Himalayas

3.    Desert

4.    Western Ghats

5.    Deccan Peninsula

6.    Gangetic Plain

7.    North-East India

8.    Islands

9.    Coastal Parts

Recent information on Anti-microbial activity of Dioscorea spp.

SanjeetKumar
Ravenshaw University

sanjeet.biotech@gmail.com

Folia Microbiol (Praha). 1996;41(5):407-12.

Antifungal properties of yam (Dioscorea alata) peel extract.

Aderiye BI, Ogundana SK, Adesanya SA, Roberts MF.

The extraction of natural antifungal compounds from the peels of yam (Dioscorea alata) and the effect of these compounds on both the vegetative and reproductive structures of some yam not pathogens were studied. Four prominent antifungal components were obtained; one of the components was fully characterized and identified as beta-sitosterol. The antifungal activity of the compounds toward the germination of spores of two yam pathogens showed an inhibition of less than 57% at a concentration of 50 mg/L while inhibition on the elongation of germ-tubes of Fusarium moniliforme was as high as 82% at the same concentration. However, the ED50 for inhibition of germ-tube elongation in the yam compounds for the same organism was below 32 mg/L. The role of the yam compounds at high concentrations in disease resistance is discussed.

Dioscorea root extract benefit and side effects by Ray Sahelian, M.D. research studies

Diosgenin is a steroidal saponin, which is extracted from the root of Wild Yam (Dioscorea villosa).

For a list of herbs used in Chinese medicine, see Chinese Herbs.

Rehmannia Endurance - With Dioscorea
Planetary Formulas
Planetary Formulas Rehmannia Endurance is based on the classic Chinese tonifer Rehmannia Six: Liu Wei Di Huang Wan, one of the most strengthening tonics of Chinese herbalism. Traditionally it was used for those who are tired and run down from overwork and inadequate rest due to a fast paced-lifestyle.

Rehmannia Supplement Facts:
Calcium - 128 mgRehmannia Root - 320 mgPoria Cocos Sclerotium - 160 mgTree Peony Root Bark - 160 mg
Dioscorea Root - 160 mg
Alisma Rhizome - 160 mg
He Shou Wu Root (Fo Ti) - 80 mgChrysanthemum Flower - 64 mg
Ligustrum Seed - 64 mgSaw Palmetto Berry - 48 mgLycii Fruit Extract - 40 mg also known as goji berry and available as a supplement.Cornus Fruit - 18 mg

Dioscorea research studies
Antioxidant activity of dioscorea and dehydroepiandrosterone (DHEA) in older humans.
Life Sci. 1996.
Araghiniknam M, Chung S, Nelson-White T, Eskelson C, Watson RR.
Arizona Prevention Center, University of Arizona, School of Medicine, Tucson
Dioscorea is a yam steroid extract used in commercial steroid synthesis and consumed by people. DHEA is a steroid which declines with age, but without known activity. This study was designed to determine whether dioscorea supplementation could increase serum dehydroepiandrosterone sulfate (DHEAS) in humans and modulate lipid levels in older people. The subjects were selected volunteers aged 65-82 years. The serum DHEAS level, lipid peroxidation and lipid profile were assessed. Three weeks of dioscorea supplementation had no affect on serum DHEAS level. However DHEA intake of 85 mg/day increased serum DHEA levels 100.3%. DHEA and dioscorea significantly reduced serum lipid peroxidation, lowered serum triglycerides, phospholipid and increased HDL levels. Both DHEA and the steroid yam extract, dioscorea, have significant activities as antioxidant to modify serum lipid levels.

Dioscorea alata (water yam) (Chinese yam)
Chinese yam (Dioscorea alata cv. Tainung No. 2) feeding exhibited antioxidative effects in hyperhomocysteinemia rats.
J Agric Food Chem. 2004.
Antioxidative effects of Dioscorea alata (D. alata) were investigated in hyperhomocysteinemia (HHcy) induced by methionine (Met) oral feeding (1 (g/kg of BW)/day). These results indicated that HHcy induced by Met could be reversed by Dioscorea alata feeding. Dioscorea alata feeding exhibited its antioxidative effects in HHcy including alleviating PA, lipid peroxidation, and oxidative stress, but did not induce activity of antioxidant enzymes which had already adaptively increased by HHcy.

Both dioscorin, the tuber storage protein of yam (Dioscorea alata cv. Tainong No. 1), and its peptic hydrolysates exhibited angiotensin converting enzyme inhibitory activities.
J Agric Food Chem. 2002.
Dioscorin, the tuber storage protein of yam (Dioscorea alata cv. Tainong No. 1), was purified to homogeneity by DE-52 ion-exchange chromatography. This purified dioscorin was shown by spectrophotometric methods to inhibit angiotensin converting enzyme (ACE) in a dose-dependent manner (12.5-750 microg, respectively, 20.83-62.5% inhibitions) using N-[3-(2-furyl)acryloyl]-Phe-Gly-Gly (FAPGG) as substrates. The 50% inhibition (IC(50)) of ACE activity was 6.404 microM dioscorin (250 microg corresponding to 7.81 nmol) compared to that of 0.00781 microM (0.0095 nmol) for captopril. The commercial bovine serum albumin and casein (bovine milk) showed less ACE inhibitory activity. The use of qualitative TLC also showed dioscorin as ACE inhibitors. Dioscorin showed mixed noncompetitive inhibitions against ACE; when 31.25 microg of dioscorin (0.8 microM) was added, the apparent inhibition constant (K(i)) was 2.738 microM. Pepsin was used for dioscorin hydrolysis at 37 degrees C for different times. It was found that the ACE inhibitory activity was increased from 51.32% to about 75% during 32 h hydrolysis. The smaller peptides were increased with increasing pepsin hydrolytic times. Dioscorin and its hydrolysates might be a potential for hypertension control when people consume yam tuber.

Effects of "Chinese yam" on hepato-nephrotoxicity of acetaminophen in rats.
Acta Pharmacol Sin. 2002.
To study the effect of yam in Taiwan, which is a commonly used Chinese medicine, on hepato-nephro-toxicity in rats. Crude water extract of yam (Dioscorea alata L), was used to treat rats with an acute toxicity induced by acetaminophen (APAP) challenge. The pharmacological and biochemical studies showed the extract of yam had the effect of kidney secureness and liver fortification. The pathologic sections showed good improvements in renal tubular degranulation changes, necrosis and disintegration. The extract of yam also possessed a good protection against the inflammation of central vein and necrosis of liver tissue. The liver and kidneys are originated from the same source. Pathologically, deficiency of the life essence in the kidney may lead to the blood deficiency in the liver. The results showed that the yam could prevent the damages of the liver and kidneys, thus preserving their functions. This could b e the reason why the yam was commonly used in traditional Chinese medicine, as seen in Liuwei Dihuang Wan be used in the case of deficiency of liver-yin and kidney-yin.Antifungal properties of yam (Dioscorea alata) peel extract.

Folia Microbiol (Praha). 1996.
The extraction of natural antifungal compounds from the peels of yam (Dioscorea alata) and the effect of these compounds on both the vegetative and reproductive structures of some yam not pathogens were studied. Four prominent antifungal components were obtained; one of the components was fully characterized and identified as beta-sitosterol. The antifungal activity of the compounds toward the germination of spores of two yam pathogens showed an inhibition of less than 57% at a concentration of 50 mg/L while inhibition on the elongation of germ-tubes of Fusarium moniliforme was as high as 82% at the same concentration. However, the ED50 for inhibition of germ-tube elongation in the yam compounds for the same organism was below 32 mg/L. The role of the yam compounds at high concentrations in disease resistance is discussed.

Nutritional assessment of yam (Dioscorea alata) tubers.
Plant Foods Hum Nutr. 1994.
The nutrient and antinutrient components of tubers from seven cultivars of Dioscorea alata were determined. The average crude protein content of D. alata tubers was 7.4%. Starch (75.6-84.3%) was the predominant fraction of the tuber dry matter. Significant differences in crude protein and starch contents were observed among cultivars. Vitamin C content of the yam tubers ranged from 13 to 24 mg/100 g fresh weight. The results showed yams to be reasonably good sources of minerals. Phytic acid contents of the yams were low, with values ranging from 58 to 198 mg/100 g dry matter. Total oxalate levels in yam tubers were found to be in the range of 486-781 mg/100 g dry matter, but may not constitute a nutritional concern since 50-75% of the oxalates were in the water-soluble form. The overall results are suggestive of the nutritional superiority of yams compared to other tropical root crops.

Dioscorea batatas
Yam (Dioscorea batatas) tuber mucilage exhibited antioxidant activities in vitro.
Planta Med. 2002.
The yam (Dioscorea batatas Decne) tuber mucilage (YTM) was extracted and partially purified by SDS and heating treatments. These results suggest that mucilage of yam tuber might play roles as antiradicals and antioxidants.

Antioxidant activities of dioscorin, the storage protein of yam (Dioscorea batatas Decne) tuber.
J Agric Food Chem. 2001.
Dioscorin, the storage protein of yam (Dioscorea batatas Decne) tuber (which is different from dioscorine found in tubers of Dioscorea hirsuta), was purified. It is suggested that 32 kDa dioscorin, the storage protein of yam tuber, may play a role as antioxidant in tubers and may be beneficial for health when people take it as a food additive or consume yam tubers.

Dioscorin, the major tuber storage protein of yam (Dioscorea batatas decne) with carbonic anhydrase and trypsin inhibitor activities.
J Agric Food Chem. 1999 May;47(5):2168-72.
Dioscorin, the tuber storage protein of yam (Dioscorea batatas Decne), was purified successively.

Dioscorea bulbifera
[Anticancer effects of various fractions extracted from Dioscorea bulbifera on mice bearing HepA]
Zhongguo Zhong Yao Za Zhi. 2004.
To investigate the anti-cancer activities and the possible mechanism of Chinese herb Dioscrea bulbifera. The herb was extracted sequentially with petroleum ether, ethanol and water. The anticancer screen were carried out in vivo with HepA in mice. The inhibitory effects on the formation of ascites volume and HepA cell viability in ascites were found in those extracted fractions except water fraction, the petroleum ether fraction being the strongest. Life span of mice bearing HepA ascites was prolonged after exposed to 100 mg x kg(-1) petroleum ether fraction and shortened after exposed to water fraction significantly. Besides, abnormal microstructure on HepA cells surface was found and it was supposed to be potential effect against viability of HepA which was convinced with the regeneration of HepA cells from ascites in mice exposed to petroleum ether fraction. Anticancer active compounds are mainly extracted by petroleum ether from hydrophobic constituents of Dioscrea bulbifera and the anticancer effects were related to direct toxicity on tumor cell.

[Experimental pathological study of subacute intoxication by Dioscorea bulbifera L]
Fa Yi Xue Za Zhi. 2003.
To study the pathological change and the toxic mechanism of Dioscorea bulbifera L in mice. METHODS: Sixty ICR mice were randomly assigned to four groups poisoned respectively with 200% Dioscorea bulbifera L of 1/4 LD50, 1/10LD50, 1/30LD50 and a control group treated with distilled water by oral administration. All animals were pathologically examined with LM and some of them were examined with TEM when the mice died during the experiment or the survival mice were sacrificed after thirty days. The pathological changes showed fatty change and the increasing glycogen of liver cells; degeneration and necrosis of the epithelia of uriniferous tubules. The serum BUN and ALT of the experimental groups mice were higher than that of control group. Enzyme histochemical staining showed the decreasing activity of G-6-P and SDH in the liver cells in the experimental groups. The experiment suggests that the target organs were liver and kidney. The toxic mechanism of Dioscorea bublifera L was the damage of the mitochondrional and endoplasmic reticulum membrane directly. As a result, the activity of the SDH and G-6-P decreased, the metabolism was affected.

Antitumor-promoting constituents from Dioscorea bulbifera L. in JB6 mouse epidermal cells.
Biol Pharm Bull. 20023.
An antitumor-promoting effect was found in the extracts/ingredients of a plant used as a traditional medicine in mainland China, using the neoplastic transformation assay of mouse epidermal JB6 cell lines. The ethyl acetate soluble fraction of 75% ethanol extract of the rhizomes of Dioscorea bulbifera L. showed an inhibitory effect against the tumor promotion of JB6 (Cl 22 and Cl 41) cells induced by a promoter, 12-O-tetradecanoylphorbol-13-acetate (TPA). Further investigation on the constituents of the EtOAc fraction from the rhizomes revealed the chemical structure to be kaempferol-3,5-dimethyl ether (1), caryatin (2), (+)-catechin (3), myricetin (4), quercetin-3-O-galactopyranoside (5), myricetin-3-O-galactopyranoside (6), myricetin-3-O-glucopyranoside (7) and diosbulbin B (8). Constituent antitumor-promoting activities were also examined in the same way. Compounds 1-7, characterized as flavonoids with the two hydroxyl groups at C-7 and C-4', showed the most potent inhibitory effect, but there seemed to be differences in the inhibitory effect between flavonol aglycones and flavonol glycosides. Compared with (-)-epicatechin, (+)-catechin exhibited much stronger inhibitory activity which suggested that chemical stereo structures of compounds affect the efficiency of inhibition. Compound 8 showed moderate activity. The constituents with antitumor-promoting activity from this plant are reported for the first time.

Dioscorea dumetorum
Pharmacological evaluation of Dioscorea dumetorum tuber used in traditional antidiabetic therapy.
J Ethnopharmacol. 1986.
This study was undertaken to confirm or otherwise disprove the alleged effectiveness of Dioscorea dumetorum tuber in the traditional treatment of clinical diabetes mellitus. Hydroalcoholic extracts of the tuber were fractionated by precipitation or solvent partition and the various extracts or fractions subjected to phytochemical and pharmacological tests. Whereas the alkaloid-containing fraction was hyperglycaemic in fasting normal mice, the whole extract and the fractions containing steroidal derivatives evinced significant hypoglycaemic activities in fasting normal mice or rabbits and in fasting alloxan-diabetic rabbits. The hypoglycaemic action of the glycosidic portion in particular was prompt and potent, in normal as well as in severely alloxan-diabetic rabbits suggesting thereby the possibility of obtaining an agent that could act in conditions of even severe insulin lack.

Dioscorea villosa
The effects of sustained delivery of diosgenin on the adrenal gland of female rats.
Biomed Sci Instrum. 2003.
University of Mississippi Medical Center, Jackson, MS
Diosgenin has been reported to have tremendous medical applications. In addition, as an herbal extract it appears to be free of any major adverse effects. Recently, Wild Yam has been used to minimize post-menopausal symptoms and is sold unregulated over the counter at a variety of pharmacy and health food stores. The specific objectives of this study were to continuously deliver diosgenin to adult ovariectomized female rats for 45 days and follow changes in body weight, organ weight and histopathological changes in the adrenal gland. Adult female Sprague Dawley rats were divided into three equal groups (n = 54, 250-300 gm BW). Rats in group I served as the control group, animals in group II were ovariectomized and animals in group II were ovariectomized, and supplemented with tricalcium phosphate (TCP) drug delivery system loaded with 500 mg diosgenin. The results indicated that ovariectomized animals had a significant increase in body weight and spleen weights. Slight increases in wet adrenal weights were observed in the ovariectomized group compared to the control animals. Histopathological evaluation of the adrenal gland revealed an increase in the cortical and medullary adrenal areas of the ovariectomized group and a significant decrease in these areas in the diosgenin treated animals. The information is considered important because reduction in adrenal mass may poses a potential for major endocrine complications.

Effects of wild yam extract on menopausal symptoms, lipids and sex hormones in healthy menopausal women.
Climacteric. 2001 Jun.
Baker Medical Research Institute, St Kilda Central, Melbourne Victoria, Australia.
Many women seek alternatives to hormonal therapies for the management of menopausal symptoms. Among the treatments currently popular are extracts of wild yam (Dioscorea villosa), which are applied topically in the form of a cream. These preparations are known to contain steroidal saponins, including diosgenin, which has been claimed to influence endogenous steroidogenesis. However, there have been no studies of the safety or efficacy of these preparations in the management of menopausal symptoms. We therefore conducted a double-blind, placebo-controlled, cross-over study of the effects of a wild yam cream in 23 healthy women suffering from troublesome symptoms of the menopause. After a 4-week baseline period, each woman was given active cream and matching placebo for 3 months in random order. Diaries were completed over the baseline period and for 1 week each month thereafter, and blood and saliva samples were collected at baseline and at 3 and 6 months, for measurement of lipids and hormones. This study suggests that short-term treatment with topical wild yam extract in women suffering from menopausal symptoms is free of side-effects, but appears to have little effect on menopausal symptoms. It emphasizes the importance of careful study of treatments for menopausal symptoms if women are to be adequately informed about the choices available to them.

Dioscorea panthaica
Steroidal saponins from Dioscorea panthaica and their cytotoxic activity.
Pharmazie. 2004.
A new steroidal saponin, dioscoreside E (1), and a known compound, protodioscin (2), were isolated from an ethanol extract of the rhizomes of Dioscorea panthaica. Compounds 1 and 2 showed cytotoxic activity against a panel of tumor cell lines.

Dioscorea tokoro
Methanol extract of Dioscoreae Rhizoma inhibits pro-inflammatory cytokines and mediators in the synoviocytes of rheumatoid arthritis.
Int Immunopharmacol. 2004.
Dioscoreae Rhizoma (MDR), the root of Dioscorea tokoro MAKINO, has been used for the treatment of arthritis, muscular pain and urinary diseases in oriental medicine. The present work evaluates a methanol extract of Dioscoreae Rhizoma (MDR). MDR did not show any cytotoxic effect on mouse lung fibroblast cells (mLFCs) or human fibroblast-like synovial cells (hFLSCs). However, it significantly reduced the proliferation of hFLSCs stimulated by interleukin-1beta (IL-1beta) and tumor necrosis factor-alpha (TNF-alpha). MDR significantly inhibited the production of TNF-alpha and IL-1beta as well as down-regulating the expression of cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) in IL-1beta- and TNF-alpha-stimulated hFLSCs. MDR also effectively reduced the level of reactive oxygen species (ROS) in these cells. Taken together, these findings provide evidence that MDR may be a candidate for the treatment of rheumatoid arthritis (RA).

A number of diocorea species have been researched including:
dioscorea villosa
dioscorea bulbifera
dioscorea elephantipes
compositae dioscorea
D batatas
dioscorea plant
dioscorea spp
dioscorea alata
dioscorea opposita thunb

Wild Yam Extract 4%, 6%, 8%, 10%, 20% Saponin Diosgenin
   

International Journal of Nanomedicine 2012:7 483–496

Sougata Ghosh1, Sumersing Patil1, Mehul Ahire1, Rohini Kitture2, Sangeeta Kale3, Karishma Pardesi4 , Swaranjit S Cameotra5, Jayesh Bellare6, Dilip D Dhavale7, Amit Jabgunde7, Balu A Chopade1

Synthesis of silver nanoparticles using Dioscorea bulbifera tuber extract and evaluation of its synergistic potential in combination with antimicrobial agents

Background: Development of an environmentally benign process for the synthesis of silver

nanomaterials is an important aspect of current nanotechnology research. Among the 600 species of the genus Dioscorea, Dioscorea bulbifera has profound therapeutic applications due to its unique phytochemistry. In this paper, we report on the rapid synthesis of silver nanoparticles by reduction of aqueous Ag+ ions using D. bulbifera tuber extract.

Methods and results: Phytochemical analysis revealed that D. bulbifera tuber extract is

rich in flavonoid, phenolics, reducing sugars, starch, diosgenin, ascorbic acid, and citric acid.

The biosynthesis process was quite fast, and silver nanoparticles were formed within 5 hours.

Ultraviolet-visible absorption spectroscopy, transmission electron microscopy, high-resolution transmission electron microscopy, energy dispersive spectroscopy, and x-ray diffraction confirmed reduction of the Ag+ ions. Varied morphology of the bioreduced silver nanoparticles included spheres, triangles, and hexagons. Optimization studies revealed that the maximum rate of synthesis could be achieved with 0.7 mM AgNO3 solution at 50°C in 5 hours. The resulting silver nanoparticles were found to possess potent antibacterial activity against both Gram-negative and Gram-positive bacteria. Beta-lactam (piperacillin) and macrolide (erythromycin) antibiotics showed a 3.6-fold and 3-fold increase, respectively, in combination with silver nanoparticles selectively against multidrug-resistant Acinetobacter baumannii. Notable synergy was seen between silver nanoparticles and chloramphenicol or vancomycin against Pseudomonas aeruginosa, and was supported by a 4.9-fold and 4.2-fold increase in zone diameter, respectively. Similarly, we found a maximum 11.8-fold increase in zone diameter of streptomycin when combined with silver nanoparticles against E. coli, providing strong evidence for the synergistic action of a combination of antibiotics and silver nanoparticles.

Conclusion: This is the first report on the synthesis of silver nanoparticles using D. Bulbifera tuber extract followed by an estimation of its synergistic potential for enhancement of the antibacterial activity of broad spectrum antimicrobial agents.

Journal of Basic Microbiology, 1989, 29(5): 265-267.

Antifungal activity of dihydrodioscorine extracted from a wild variety of Dioscorea bulbifera L

Adetoun Adeleye,  Dr. T. Ikotun^*

DOI: 10.1002/jobm.3620290504

The bulbils and tubers of a wild variety of Dioscorea bulbifera L. contained an alkaloid, dihydrodioscorine. When crystallized in its hydrochloride form and incorporated into potato dextrose agar at a final concentration of 0.1%, it was found to slow down the rate of growth of five plant pathogenic fungi namely: Sclerotium rolfsii, Curvularia lunata, Fusarium moniliforme, Macrophomina phaseolina and Botryodiplodiatheobromae. Also sclerotia formation in S. rolfsii was delayed and the number was reduced. Conidia formation in C. lunata and F. moniliforme was also delayed and reduced but pycnidia formation in M. phaseolina and B. theobromae was not affected. There was no significant difference between the rate of growth of the fungi on PDA incorporated with 0.01% final concentration of dihydrodioscorine and on control plates. Abbreviations: PDA = potato dextrose agar, D.D. = dihydrodioscorine dihydrochloride.

Journal of Applied Biosciences (J. Appl. Biosci.) [ISSN 1997 - 5902]

Volume 51: 3583 - 3590. Published March 29, 2012.

In vitro antimicrobial and antioxidant analysis of Dioscorea dumetorum (Kunth) Pax and Dioscorea hirtiflora (Linn.) and their bioactive metabolitesfrom Nigeria

Mubo Adeola Sonibare*, Rebecca Busayo Abegunde
Department of Pharmacognosy, Faculty of Pharmacy, University of Ibadan, Ibadan Nigeria

RESUME

Objectives: To analyze total phenols, flavonoids, antioxidant potential and antimicrobial activity of tuber extracts of two Dioscorea species.
Methodology and results: 1, 1-diphenyl-2-picrylhydrazyl (DPPH) assay and Folin-Ciocalteu reagent were used to determine total antioxidant activity and total phenolic content of tuber extracts of D. dumetorum (edible and wild species) and D. hirtiflora. Total Flavonoids were determined by repeatedly extracting 1 g of powdered tuber sample with 10ml of 80% aqueous methanol at room temperature for 2-4 hours. Anti-microbial activity was determined by Agar diffusion and pour plate methods. Quantitative analysis of bioactive components revealed that total phenols are the major bioactive constituents found in the extracts expressed as mg of GAE per gram, which ranged from 22.83 ± 0.33mg/g to 64.33 ± 2.55mg/g. Mean concentrations of flavonoids ranged from 7.53± 0.07 mg/g to 25.60 ± 0.39 mg/g. Anti-oxidant efficiency was higher in D.  hirtiflora and non-edible D. dumetorum than edible D. dumetorum when compared to standard antioxidants like Ascorbic acid. Antimicrobial activity profile showed direct influence of concentrations of bioactive components.
Conclusion and application of findings: The results of our study confirmed the folkloric uses of the studied plants and provided evidence that tuber extracts of D. dumetorum and D. hirtiflora might indeed be potential sources of natural antioxidant and antimicrobial agents.
Key words: Dioscorea, antimicrobial activity, antioxidant activity, bioactive compounds. 

Latest Research on antimicrobial activity of Dioscorea species

Sanjeet Kumar
Ravenshaw University

sanjeet.biotech@gmail.com

Letters in Applied Microbiology 46 (2008) 68–72

Fungal endophytes from Dioscorea zingiberensis rhizomes

and their antibacterial activity

L. Xu1, L. Zhou1, J. Zhao1, J. Li1, X. Li2 and J. Wang

Aims:  The aim of the study was to isolate and characterize the endophytic fungi from the rhizomes of the Chinese traditional medicinal plant Dioscorea zingiberensis and to detect their antibacterial activities.

Methods and Results:  After strict sterile sample preparation, nine fungal endophytes were isolated from rhizomes of the Chinese traditional medicinal plant D. zingiberensis. The endophytes were classified by morphological traits and internal transcribed spacer (ITS) rRNA gene sequence analysis. Their ITS rDNA sequences were 99–100% identical to Nectria, Fusarium, Rhizopycnis, Acremonium and Penicillium spp. respectively. Of these, the most frequent genera were Fusarium and Nectria. One isolate, Dzf7, was unclassified on the basis of its low sequence similarity. The next closest species was Alternaria longissima (c. 92·4% sequence similarity). Endophyte isolate Dzf5 showed the closest sequence similarity (c. 99·5%) to an uncultured soil fungus (DQ420800) obtained from Cedar Creek, USA. Bioassays using a modified broth dilution test were used to detect the antibacterial activity of n-butanol extracts of both mycelia and culture filtrates of D. zingiberensis showed biological activity against Bacillus subtilis, Staphylococcus haemolyticus, Escherichia coli and Xanthomonas vesicatoria. Minimal inhibitory concentration (MIC) values of the extracts were between 31·25 μg ml⁻¹ and 125 μg ml⁻¹.

Conclusions:  Endophytic fungus Dzf2 (c. 99·8% sequence similarity to Fusarium redolens) isolated from D. zingiberensis rhizome showed the most potent antibacterial activities.

Significance and Impact of the Study:  Endophytic fungi isolated from D. zingiberensis may be used as potential producers of antibacterial natural products.

Year : 2003  |  Volume : 65  |  Issue : 2  |  Page : 195-196 Indian Journal of Pharmaceutical Sciences

Antimicrobial Activity Of Dioscorea Bulbifera Bulbils Y.N Seetharam, G Jyothishwaran, H Sujeeth, A Barad, G Sharanabasappa, D Shivkumar

The successive extracts of Dioscorea bulbifera (bulbils) has been investigated for in vitro antimicrobial activity against Klebsiella pneumoniae, Escherichia coli, Bacillus aureus, Proteus vulgaris, Staphylococcus aureus, Aspergillus niger, Aspergillus flavus, Aspergillus fumigatus and Rhizopus nigricans. The petroleum ether and chloroform extracts showed significant activity against A. fumigatus and R. nigricans. The petroleum ether and distilled water extract showed good activity against K. pneumoniae. The chloroform extract showed feeble activity against S. aureus.

Int J Pharm Pharm Sci, Vol 4, Issue 1, 314-316  

EVALUATION OF THE ANTIBACTERIAL ACTIVITY OF ETHANOLIC EXTRACT OF DIOSCOREA VILLOSA TUBERS- AN IN VITRO STUDY

ANITHA ROY ^1*, GEETHA R.V² AND LAKSHMI T¹

¹Faculty of Pharmacology, ²Faculty of Microbiology, Saveetha Dental College, Velappanchavady, Chennai 77. Email: anitharoypeeter@yahoo.co.in

Received: 26 Aug 2011, Revised and Accepted: 19 Nov 2011

ABSTRACT

The aim of the present study was to evaluate the anti bacterial activity of the ethanolic extract of Dioscorea villosa (wild yam) tubers. Dioscorea villosa (dioscoraceae) is used for centuries as a medicinal herb for a wide range of ailments. It is a tuberous, twining vine with pale- brown, knotty, wood and cylindrical tubers. Wild yam is sometimes suggested as an alternative to hormone replacement therapy. The ethanolic extract of Dioscorea villosa tubers was screened for its antibacterial activity against Shigella dysenteriae, E.coli, Vibrio cholera, Klebsiella pneumonia, Psuedomonas aerugenosa, Staphylococcus aureus, using disc diffusion technique .The results of this study showed good anti bacterial activity against the bacterial species tested, at different concentrations of the extract.

Antimicrobial Activity of Ficus Leaf Extracts on Some Fungal and Bacterial Pathogens of Dioscorea rotundata from Southwest Nigeria
O.A. Oyelana, E.U. Durugbo, O.D. Olukanni, E.A. Ayodele, Z.O. Aikulola and A.I. Adewole
ABSTRACT
Bio-control methods have become a common practice in horticulture and crop husbandry due to the attendant negative impact of fungicides and other chemical agents on soil, vegetation and environment. Most fungicides accumulate in plant tissues and subsequently trigger carcinogenic effects in animals and humans. The leaf extracts of Ficus thonningii, F. saussureana, F. exasperata and F. sur were screened for antimicrobial properties on eight (8) fungal species which included Aspergillus flavus, A. niger, Botryodiploidia theobromae, Fusarium oxysporum, F. solani, Penicillium chrysogenum, P. oxalicum and Rhizopus stolonifer and two (2) bacterial species viz; Pseudomonas spp. and Klebsiella spp. which were isolated from the rot portions of tubers of Dioscorea rotundata. The extracts from the Ficus species had low antimicrobial effect at 25 and 50 mg mL-1 concentrations while a significant arrest of mycelia growth was observed at 75 and 100 mg mL-1 concentrations. The presence of alkaloids, flavonoids and cardiac glycosides in the leaves of these species may have conferred the antimicrobial properties on these species. Application of the fungal pathogens isolated on healthy tubers and the subsequent development of rots confirmed these organisms as the natural pathogens of this crop. The extracts from all the four Ficus species exerted significant antimicrobial effect on all the test organisms at 75 and 100 mg mL-1 concentrations and its application at these concentrations would help to minimise infection and spoilage during and after storage and improve farmers’ revenue.

Science Alert

Sonibare and Abegunde J. Appl. Biosci. 2012 In vitro antimicrobial and antioxidant analysis of Dioscorea species

In vitro antimicrobial and antioxidant analysis of Dioscorea dumetorum (Kunth) Pax and Dioscorea hirtiflora (Linn.) and their bioactive metabolites from Nigeria

Objectives: To analyze total phenols, flavonoids, antioxidant potential and antimicrobial activity of tuber extracts of two Dioscorea species. Methodology and results: 1, 1-diphenyl-2-picrylhydrazyl (DPPH) assay and Folin-Ciocalteu reagent were used to determine total antioxidant activity and total phenolic content of tuber extracts of D. Dumetorum (edible and wild species) and D. hirtiflora. Total Flavonoids were determined by repeatedly extracting 1 g of powdered tuber sample with 10ml of 80% aqueous methanol at room temperature for 2-4 hours. Antimicrobial activity was determined by Agar diffusion and pour plate methods. Quantitative analysis of bioactive components revealed that total phenols are the major bioactive constituents found in the extracts expressed as mg of GAE per gram, which ranged from 22.83 ± 0.33mg/g to 64.33 ± 2.55mg/g. Mean concentrations of flavonoids ranged from 7.53± 0.07 mg/g to 25.60 ± 0.39 mg/g. Anti-oxidant efficiency was higher in D. hirtiflora and non-edible D. dumetorum than edible D. dumetorum when compared to standard antioxidants like Ascorbic acid. Antimicrobial activity profile showed direct influence of concentrations of bioactive components. Conclusion and application of findings: The results of our study confirmed the folkloric uses of the studied plants and provided evidence that tuber extracts of D. dumetorum and D. hirtiflora might indeed be potential sources of natural antioxidant and antimicrobial agents.

Kaladhar et al / Journal of Pharmaceutical Science and Technology Vol. 2 (8), 2010,284-287

Comparative Antimicrobial Studies of Dioscorea Hamiltonii hook.f.tubers with Azadirachta Indica Stem

Antimicrobial activity of tuber extract of Dioscorea hamiltonii Hook.f. and stem extracts of Azadirachta indica was comparatively studied against Aspergillus niger, Bacillus subtilis, Enterococcus faecalis, Escherichia coli, Lactobacillus delbrueckii subsp lactis, Penicillium chrysogenum, Proteus Vulgaris, Pseudomonas aeruginosa, Saccharomyces cerevisiae, Streptococcus pyogenes, Streptococcus thermophilus and Vibrio parahaemolyticus. Methanolic and Ethyl acetate leaf extracts from D.hamiltonii and A.indica has shown good antimicrobial activity against tested microbes (9 to 25mm zone diameter). The extract has shown good activity against Gram positive bacteria (14 to 25mm), when compared with Gram negative bacteria (12 to 23) and fungi (9 to 15mm, except S.cerevisiae-17 to 24mm). Higher concentrations of extracts are required to retard the growth of fungi.

Toxicol Int. 2012 May-Aug; 19(2): 100–105.

doi:  10.4103/0971-6580.97195

PMCID: PMC3388750

Bio-efficacy of Dioscorea pentaphylla from Midmid-Western Ghats, India

G. Prakash and B. B. Hosetti

Department of Applied Zoology, Toxicology Lab, Kuvempu University, Shankaraghatta – 577 451, India

Address for correspondence: Dr. G. Prakash, Toxicology Lab, Department of Applied Zoology, Kuvempu University, Shankaraghatta – 577 451, India. E-mail: prakash.geriyol/at/gmail.com

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Abstract

Antibacterial and antifungal activity of crude extracts of medicinally important and traditionally used yam plant, Dioscorea pentaphylla, from mid-Western Ghats was evaluated against 27 bacterial and 5 fungal clinical strains collected of the patients from infectious sources. The clinical strains belonging to their respective species showed concentration-dependent susceptibility toward crude petroleum ether extract, chloroform extract and methanol extract at 100 μg/100 μl. The extracts exhibited predominant antibacterial activity against Staphylococcus aureus (ATCC-20852), Pseudomonas aeruginosa (ATCC-29737) and Klebsiella pneumoniae (MTCC-618), respectively, and five clinically isolated pathogenic fungi, Trichophyton rubrum, Microsporum gypseum, Tricophyton tonsurans, Microsporum audouini, and Candida albicans, with antibacterial drug ciprofloxacin and antifungal drug fluconozole (50 μg/100 μl) as standards. Out of the three extracts, ethanol extracts possessed better minimum inhibitory concentration (MIC) against all the bacterial strains. All the three extracts showed significant activity against all the five fungal pathogen strains. The results are promising and support the traditional use of D. pentaphylla for the treatment of bacterial and fungal infections.

Folia Microbiol (Praha). 1996;41(5):407-12.

Antifungal properties of yam (Dioscorea alata) peel extract.

Aderiye BI, Ogundana SK, Adesanya SA, Roberts MF.

The extraction of natural antifungal compounds from the peels of yam (Dioscorea alata) and the effect of these compounds on both the vegetative and reproductive structures of some yam not pathogens were studied. Four prominent antifungal components were obtained; one of the components was fully characterized and identified as beta-sitosterol. The antifungal activity of the compounds toward the germination of spores of two yam pathogens showed an inhibition of less than 57% at a concentration of 50 mg/L while inhibition on the elongation of germ-tubes of Fusarium moniliforme was as high as 82% at the same concentration. However, the ED50 for inhibition of germ-tube elongation in the yam compounds for the same organism was below 32 mg/L. The role of the yam compounds at high concentrations in disease resistance is discussed.

Dioscorea root extract benefit and side effects by Ray Sahelian, M.D. research studies

Diosgenin is a steroidal saponin, which is extracted from the root of Wild Yam (Dioscorea villosa).

For a list of herbs used in Chinese medicine, see Chinese Herbs.

Rehmannia Endurance - With Dioscorea
Planetary Formulas
Planetary Formulas Rehmannia Endurance is based on the classic Chinese tonifer Rehmannia Six: Liu Wei Di Huang Wan, one of the most strengthening tonics of Chinese herbalism. Traditionally it was used for those who are tired and run down from overwork and inadequate rest due to a fast paced-lifestyle.

Rehmannia Supplement Facts:
Calcium - 128 mg
Rehmannia Root - 320 mg
Poria Cocos Sclerotium - 160 mg
Tree Peony Root Bark - 160 mg
Dioscorea Root - 160 mg
Alisma Rhizome - 160 mg
He Shou Wu Root (Fo Ti) - 80 mg
Chrysanthemum Flower - 64 mg
Ligustrum Seed - 64 mg
Saw Palmetto Berry - 48 mg
Lycii Fruit Extract - 40 mg also known as goji berry and available as a supplement.
Cornus Fruit - 18 mg

Dioscorea research studies
Antioxidant activity of dioscorea and dehydroepiandrosterone (DHEA) in older humans.
Life Sci. 1996.
Araghiniknam M, Chung S, Nelson-White T, Eskelson C, Watson RR.
Arizona Prevention Center, University of Arizona, School of Medicine, Tucson
Dioscorea is a yam steroid extract used in commercial steroid synthesis and consumed by people. DHEA is a steroid which declines with age, but without known activity. This study was designed to determine whether dioscorea supplementation could increase serum dehydroepiandrosterone sulfate (DHEAS) in humans and modulate lipid levels in older people. The subjects were selected volunteers aged 65-82 years. The serum DHEAS level, lipid peroxidation and lipid profile were assessed. Three weeks of dioscorea supplementation had no affect on serum DHEAS level. However DHEA intake of 85 mg/day increased serum DHEA levels 100.3%. DHEA and dioscorea significantly reduced serum lipid peroxidation, lowered serum triglycerides, phospholipid and increased HDL levels. Both DHEA and the steroid yam extract, dioscorea, have significant activities as antioxidant to modify serum lipid levels.

Dioscorea alata (water yam) (Chinese yam)
Chinese yam (Dioscorea alata cv. Tainung No. 2) feeding exhibited antioxidative effects in hyperhomocysteinemia rats.
J Agric Food Chem. 2004.
Antioxidative effects of Dioscorea alata (D. alata) were investigated in hyperhomocysteinemia (HHcy) induced by methionine (Met) oral feeding (1 (g/kg of BW)/day). These results indicated that HHcy induced by Met could be reversed by Dioscorea alata feeding. Dioscorea alata feeding exhibited its antioxidative effects in HHcy including alleviating PA, lipid peroxidation, and oxidative stress, but did not induce activity of antioxidant enzymes which had already adaptively increased by HHcy.

Both dioscorin, the tuber storage protein of yam (Dioscorea alata cv. Tainong No. 1), and its peptic hydrolysates exhibited angiotensin converting enzyme inhibitory activities.
J Agric Food Chem. 2002.
Dioscorin, the tuber storage protein of yam (Dioscorea alata cv. Tainong No. 1), was purified to homogeneity by DE-52 ion-exchange chromatography. This purified dioscorin was shown by spectrophotometric methods to inhibit angiotensin converting enzyme (ACE) in a dose-dependent manner (12.5-750 microg, respectively, 20.83-62.5% inhibitions) using N-[3-(2-furyl)acryloyl]-Phe-Gly-Gly (FAPGG) as substrates. The 50% inhibition (IC(50)) of ACE activity was 6.404 microM dioscorin (250 microg corresponding to 7.81 nmol) compared to that of 0.00781 microM (0.0095 nmol) for captopril. The commercial bovine serum albumin and casein (bovine milk) showed less ACE inhibitory activity. The use of qualitative TLC also showed dioscorin as ACE inhibitors. Dioscorin showed mixed noncompetitive inhibitions against ACE; when 31.25 microg of dioscorin (0.8 microM) was added, the apparent inhibition constant (K(i)) was 2.738 microM. Pepsin was used for dioscorin hydrolysis at 37 degrees C for different times. It was found that the ACE inhibitory activity was increased from 51.32% to about 75% during 32 h hydrolysis. The smaller peptides were increased with increasing pepsin hydrolytic times. Dioscorin and its hydrolysates might be a potential for hypertension control when people consume yam tuber.

Effects of "Chinese yam" on hepato-nephrotoxicity of acetaminophen in rats.
Acta Pharmacol Sin. 2002.
To study the effect of yam in Taiwan, which is a commonly used Chinese medicine, on hepato-nephro-toxicity in rats. Crude water extract of yam (Dioscorea alata L), was used to treat rats with an acute toxicity induced by acetaminophen (APAP) challenge. The pharmacological and biochemical studies showed the extract of yam had the effect of kidney secureness and liver fortification. The pathologic sections showed good improvements in renal tubular degranulation changes, necrosis and disintegration. The extract of yam also possessed a good protection against the inflammation of central vein and necrosis of liver tissue. The liver and kidneys are originated from the same source. Pathologically, deficiency of the life essence in the kidney may lead to the blood deficiency in the liver. The results showed that the yam could prevent the damages of the liver and kidneys, thus preserving their functions. This could b e the reason why the yam was commonly used in traditional Chinese medicine, as seen in Liuwei Dihuang Wan be used in the case of deficiency of liver-yin and kidney-yin.Antifungal properties of yam (Dioscorea alata) peel extract.

Folia Microbiol (Praha). 1996.
The extraction of natural antifungal compounds from the peels of yam (Dioscorea alata) and the effect of these compounds on both the vegetative and reproductive structures of some yam not pathogens were studied. Four prominent antifungal components were obtained; one of the components was fully characterized and identified as beta-sitosterol. The antifungal activity of the compounds toward the germination of spores of two yam pathogens showed an inhibition of less than 57% at a concentration of 50 mg/L while inhibition on the elongation of germ-tubes of Fusarium moniliforme was as high as 82% at the same concentration. However, the ED50 for inhibition of germ-tube elongation in the yam compounds for the same organism was below 32 mg/L. The role of the yam compounds at high concentrations in disease resistance is discussed.

Nutritional assessment of yam (Dioscorea alata) tubers.
Plant Foods Hum Nutr. 1994.
The nutrient and antinutrient components of tubers from seven cultivars of Dioscorea alata were determined. The average crude protein content of D. alata tubers was 7.4%. Starch (75.6-84.3%) was the predominant fraction of the tuber dry matter. Significant differences in crude protein and starch contents were observed among cultivars. Vitamin C content of the yam tubers ranged from 13 to 24 mg/100 g fresh weight. The results showed yams to be reasonably good sources of minerals. Phytic acid contents of the yams were low, with values ranging from 58 to 198 mg/100 g dry matter. Total oxalate levels in yam tubers were found to be in the range of 486-781 mg/100 g dry matter, but may not constitute a nutritional concern since 50-75% of the oxalates were in the water-soluble form. The overall results are suggestive of the nutritional superiority of yams compared to other tropical root crops.

Dioscorea batatas
Yam (Dioscorea batatas) tuber mucilage exhibited antioxidant activities in vitro.
Planta Med. 2002.
The yam (Dioscorea batatas Decne) tuber mucilage (YTM) was extracted and partially purified by SDS and heating treatments. These results suggest that mucilage of yam tuber might play roles as antiradicals and antioxidants.

Antioxidant activities of dioscorin, the storage protein of yam (Dioscorea batatas Decne) tuber.
J Agric Food Chem. 2001.
Dioscorin, the storage protein of yam (Dioscorea batatas Decne) tuber (which is different from dioscorine found in tubers of Dioscorea hirsuta), was purified. It is suggested that 32 kDa dioscorin, the storage protein of yam tuber, may play a role as antioxidant in tubers and may be beneficial for health when people take it as a food additive or consume yam tubers.

Dioscorin, the major tuber storage protein of yam (Dioscorea batatas decne) with carbonic anhydrase and trypsin inhibitor activities.
J Agric Food Chem. 1999 May;47(5):2168-72.
Dioscorin, the tuber storage protein of yam (Dioscorea batatas Decne), was purified successively.

Dioscorea bulbifera
[Anticancer effects of various fractions extracted from Dioscorea bulbifera on mice bearing HepA]
Zhongguo Zhong Yao Za Zhi. 2004.
To investigate the anti-cancer activities and the possible mechanism of Chinese herb Dioscrea bulbifera. The herb was extracted sequentially with petroleum ether, ethanol and water. The anticancer screen were carried out in vivo with HepA in mice. The inhibitory effects on the formation of ascites volume and HepA cell viability in ascites were found in those extracted fractions except water fraction, the petroleum ether fraction being the strongest. Life span of mice bearing HepA ascites was prolonged after exposed to 100 mg x kg(-1) petroleum ether fraction and shortened after exposed to water fraction significantly. Besides, abnormal microstructure on HepA cells surface was found and it was supposed to be potential effect against viability of HepA which was convinced with the regeneration of HepA cells from ascites in mice exposed to petroleum ether fraction. Anticancer active compounds are mainly extracted by petroleum ether from hydrophobic constituents of Dioscrea bulbifera and the anticancer effects were related to direct toxicity on tumor cell.

[Experimental pathological study of subacute intoxication by Dioscorea bulbifera L]
Fa Yi Xue Za Zhi. 2003.
To study the pathological change and the toxic mechanism of Dioscorea bulbifera L in mice. METHODS: Sixty ICR mice were randomly assigned to four groups poisoned respectively with 200% Dioscorea bulbifera L of 1/4 LD50, 1/10LD50, 1/30LD50 and a control group treated with distilled water by oral administration. All animals were pathologically examined with LM and some of them were examined with TEM when the mice died during the experiment or the survival mice were sacrificed after thirty days. The pathological changes showed fatty change and the increasing glycogen of liver cells; degeneration and necrosis of the epithelia of uriniferous tubules. The serum BUN and ALT of the experimental groups mice were higher than that of control group. Enzyme histochemical staining showed the decreasing activity of G-6-P and SDH in the liver cells in the experimental groups. The experiment suggests that the target organs were liver and kidney. The toxic mechanism of Dioscorea bublifera L was the damage of the mitochondrional and endoplasmic reticulum membrane directly. As a result, the activity of the SDH and G-6-P decreased, the metabolism was affected.

Antitumor-promoting constituents from Dioscorea bulbifera L. in JB6 mouse epidermal cells.
Biol Pharm Bull. 20023.
An antitumor-promoting effect was found in the extracts/ingredients of a plant used as a traditional medicine in mainland China, using the neoplastic transformation assay of mouse epidermal JB6 cell lines. The ethyl acetate soluble fraction of 75% ethanol extract of the rhizomes of Dioscorea bulbifera L. showed an inhibitory effect against the tumor promotion of JB6 (Cl 22 and Cl 41) cells induced by a promoter, 12-O-tetradecanoylphorbol-13-acetate (TPA). Further investigation on the constituents of the EtOAc fraction from the rhizomes revealed the chemical structure to be kaempferol-3,5-dimethyl ether (1), caryatin (2), (+)-catechin (3), myricetin (4), quercetin-3-O-galactopyranoside (5), myricetin-3-O-galactopyranoside (6), myricetin-3-O-glucopyranoside (7) and diosbulbin B (8). Constituent antitumor-promoting activities were also examined in the same way. Compounds 1-7, characterized as flavonoids with the two hydroxyl groups at C-7 and C-4', showed the most potent inhibitory effect, but there seemed to be differences in the inhibitory effect between flavonol aglycones and flavonol glycosides. Compared with (-)-epicatechin, (+)-catechin exhibited much stronger inhibitory activity which suggested that chemical stereo structures of compounds affect the efficiency of inhibition. Compound 8 showed moderate activity. The constituents with antitumor-promoting activity from this plant are reported for the first time.

Dioscorea dumetorum
Pharmacological evaluation of Dioscorea dumetorum tuber used in traditional antidiabetic therapy.
J Ethnopharmacol. 1986.
This study was undertaken to confirm or otherwise disprove the alleged effectiveness of Dioscorea dumetorum tuber in the traditional treatment of clinical diabetes mellitus. Hydroalcoholic extracts of the tuber were fractionated by precipitation or solvent partition and the various extracts or fractions subjected to phytochemical and pharmacological tests. Whereas the alkaloid-containing fraction was hyperglycaemic in fasting normal mice, the whole extract and the fractions containing steroidal derivatives evinced significant hypoglycaemic activities in fasting normal mice or rabbits and in fasting alloxan-diabetic rabbits. The hypoglycaemic action of the glycosidic portion in particular was prompt and potent, in normal as well as in severely alloxan-diabetic rabbits suggesting thereby the possibility of obtaining an agent that could act in conditions of even severe insulin lack.

Dioscorea villosa
The effects of sustained delivery of diosgenin on the adrenal gland of female rats.
Biomed Sci Instrum. 2003.
University of Mississippi Medical Center, Jackson, MS
Diosgenin has been reported to have tremendous medical applications. In addition, as an herbal extract it appears to be free of any major adverse effects. Recently, Wild Yam has been used to minimize post-menopausal symptoms and is sold unregulated over the counter at a variety of pharmacy and health food stores. The specific objectives of this study were to continuously deliver diosgenin to adult ovariectomized female rats for 45 days and follow changes in body weight, organ weight and histopathological changes in the adrenal gland. Adult female Sprague Dawley rats were divided into three equal groups (n = 54, 250-300 gm BW). Rats in group I served as the control group, animals in group II were ovariectomized and animals in group II were ovariectomized, and supplemented with tricalcium phosphate (TCP) drug delivery system loaded with 500 mg diosgenin. The results indicated that ovariectomized animals had a significant increase in body weight and spleen weights. Slight increases in wet adrenal weights were observed in the ovariectomized group compared to the control animals. Histopathological evaluation of the adrenal gland revealed an increase in the cortical and medullary adrenal areas of the ovariectomized group and a significant decrease in these areas in the diosgenin treated animals. The information is considered important because reduction in adrenal mass may poses a potential for major endocrine complications.

Effects of wild yam extract on menopausal symptoms, lipids and sex hormones in healthy menopausal women.
Climacteric. 2001 Jun.
Baker Medical Research Institute, St Kilda Central, Melbourne Victoria, Australia.
Many women seek alternatives to hormonal therapies for the management of menopausal symptoms. Among the treatments currently popular are extracts of wild yam (Dioscorea villosa), which are applied topically in the form of a cream. These preparations are known to contain steroidal saponins, including diosgenin, which has been claimed to influence endogenous steroidogenesis. However, there have been no studies of the safety or efficacy of these preparations in the management of menopausal symptoms. We therefore conducted a double-blind, placebo-controlled, cross-over study of the effects of a wild yam cream in 23 healthy women suffering from troublesome symptoms of the menopause. After a 4-week baseline period, each woman was given active cream and matching placebo for 3 months in random order. Diaries were completed over the baseline period and for 1 week each month thereafter, and blood and saliva samples were collected at baseline and at 3 and 6 months, for measurement of lipids and hormones. This study suggests that short-term treatment with topical wild yam extract in women suffering from menopausal symptoms is free of side-effects, but appears to have little effect on menopausal symptoms. It emphasizes the importance of careful study of treatments for menopausal symptoms if women are to be adequately informed about the choices available to them.

Dioscorea panthaica
Steroidal saponins from Dioscorea panthaica and their cytotoxic activity.
Pharmazie. 2004.
A new steroidal saponin, dioscoreside E (1), and a known compound, protodioscin (2), were isolated from an ethanol extract of the rhizomes of Dioscorea panthaica. Compounds 1 and 2 showed cytotoxic activity against a panel of tumor cell lines.

Dioscorea tokoro
Methanol extract of Dioscoreae Rhizoma inhibits pro-inflammatory cytokines and mediators in the synoviocytes of rheumatoid arthritis.
Int Immunopharmacol. 2004.
Dioscoreae Rhizoma (MDR), the root of Dioscorea tokoro MAKINO, has been used for the treatment of arthritis, muscular pain and urinary diseases in oriental medicine. The present work evaluates a methanol extract of Dioscoreae Rhizoma (MDR). MDR did not show any cytotoxic effect on mouse lung fibroblast cells (mLFCs) or human fibroblast-like synovial cells (hFLSCs). However, it significantly reduced the proliferation of hFLSCs stimulated by interleukin-1beta (IL-1beta) and tumor necrosis factor-alpha (TNF-alpha). MDR significantly inhibited the production of TNF-alpha and IL-1beta as well as down-regulating the expression of cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) in IL-1beta- and TNF-alpha-stimulated hFLSCs. MDR also effectively reduced the level of reactive oxygen species (ROS) in these cells. Taken together, these findings provide evidence that MDR may be a candidate for the treatment of rheumatoid arthritis (RA).

A number of diocorea species have been researched including:
dioscorea villosa
dioscorea bulbifera
dioscorea elephantipes
compositae dioscorea
D batatas
dioscorea plant
dioscorea spp
dioscorea alata
dioscorea opposita thunb

Wild Yam Extract 4%, 6%, 8%, 10%, 20% Saponin Diosgenin
   

International Journal of Nanomedicine 2012:7 483–496

Sougata Ghosh1, Sumersing Patil1, Mehul Ahire1, Rohini Kitture2, Sangeeta Kale3, Karishma Pardesi4 , Swaranjit S Cameotra5, Jayesh Bellare6, Dilip D Dhavale7, Amit Jabgunde7, Balu A Chopade1

Synthesis of silver nanoparticles using Dioscorea bulbifera tuber extract and evaluation of its synergistic potential in combination with antimicrobial agents

Background: Development of an environmentally benign process for the synthesis of silver

nanomaterials is an important aspect of current nanotechnology research. Among the 600 species of the genus Dioscorea, Dioscorea bulbifera has profound therapeutic applications due to its unique phytochemistry. In this paper, we report on the rapid synthesis of silver nanoparticles by reduction of aqueous Ag+ ions using D. bulbifera tuber extract.

Methods and results: Phytochemical analysis revealed that D. bulbifera tuber extract is

rich in flavonoid, phenolics, reducing sugars, starch, diosgenin, ascorbic acid, and citric acid.

The biosynthesis process was quite fast, and silver nanoparticles were formed within 5 hours.

Ultraviolet-visible absorption spectroscopy, transmission electron microscopy, high-resolution transmission electron microscopy, energy dispersive spectroscopy, and x-ray diffraction confirmed reduction of the Ag+ ions. Varied morphology of the bioreduced silver nanoparticles included spheres, triangles, and hexagons. Optimization studies revealed that the maximum rate of synthesis could be achieved with 0.7 mM AgNO3 solution at 50°C in 5 hours. The resulting silver nanoparticles were found to possess potent antibacterial activity against both Gram-negative and Gram-positive bacteria. Beta-lactam (piperacillin) and macrolide (erythromycin) antibiotics showed a 3.6-fold and 3-fold increase, respectively, in combination with silver nanoparticles selectively against multidrug-resistant Acinetobacter baumannii. Notable synergy was seen between silver nanoparticles and chloramphenicol or vancomycin against Pseudomonas aeruginosa, and was supported by a 4.9-fold and 4.2-fold increase in zone diameter, respectively. Similarly, we found a maximum 11.8-fold increase in zone diameter of streptomycin when combined with silver nanoparticles against E. coli, providing strong evidence for the synergistic action of a combination of antibiotics and silver nanoparticles.

Conclusion: This is the first report on the synthesis of silver nanoparticles using D. Bulbifera tuber extract followed by an estimation of its synergistic potential for enhancement of the antibacterial activity of broad spectrum antimicrobial agents.

Journal of Basic Microbiology, 1989, 29(5): 265-267.

Antifungal activity of dihydrodioscorine extracted from a wild variety of Dioscorea bulbifera L

Adetoun Adeleye,  Dr. T. Ikotun^*

DOI: 10.1002/jobm.3620290504

The bulbils and tubers of a wild variety of Dioscorea bulbifera L. contained an alkaloid, dihydrodioscorine. When crystallized in its hydrochloride form and incorporated into potato dextrose agar at a final concentration of 0.1%, it was found to slow down the rate of growth of five plant pathogenic fungi namely: Sclerotium rolfsii, Curvularia lunata, Fusarium moniliforme, Macrophomina phaseolina and Botryodiplodiatheobromae. Also sclerotia formation in S. rolfsii was delayed and the number was reduced. Conidia formation in C. lunata and F. moniliforme was also delayed and reduced but pycnidia formation in M. phaseolina and B. theobromae was not affected. There was no significant difference between the rate of growth of the fungi on PDA incorporated with 0.01% final concentration of dihydrodioscorine and on control plates. Abbreviations: PDA = potato dextrose agar, D.D. = dihydrodioscorine dihydrochloride.

Journal of Applied Biosciences (J. Appl. Biosci.) [ISSN 1997 - 5902]

Volume 51: 3583 - 3590. Published March 29, 2012.

In vitro antimicrobial and antioxidant analysis of Dioscorea dumetorum (Kunth) Pax and Dioscorea hirtiflora (Linn.) and their bioactive metabolitesfrom Nigeria

Mubo Adeola Sonibare*, Rebecca Busayo Abegunde
Department of Pharmacognosy, Faculty of Pharmacy, University of Ibadan, Ibadan Nigeria

RESUME

Objectives: To analyze total phenols, flavonoids, antioxidant potential and antimicrobial activity of tuber extracts of two Dioscorea species.
Methodology and results: 1, 1-diphenyl-2-picrylhydrazyl (DPPH) assay and Folin-Ciocalteu reagent were used to determine total antioxidant activity and total phenolic content of tuber extracts of D. dumetorum (edible and wild species) and D. hirtiflora. Total Flavonoids were determined by repeatedly extracting 1 g of powdered tuber sample with 10ml of 80% aqueous methanol at room temperature for 2-4 hours. Anti-microbial activity was determined by Agar diffusion and pour plate methods. Quantitative analysis of bioactive components revealed that total phenols are the major bioactive constituents found in the extracts expressed as mg of GAE per gram, which ranged from 22.83 ± 0.33mg/g to 64.33 ± 2.55mg/g. Mean concentrations of flavonoids ranged from 7.53± 0.07 mg/g to 25.60 ± 0.39 mg/g. Anti-oxidant efficiency was higher in D.  hirtiflora and non-edible D. dumetorum than edible D. dumetorum when compared to standard antioxidants like Ascorbic acid. Antimicrobial activity profile showed direct influence of concentrations of bioactive components.
Conclusion and application of findings: The results of our study confirmed the folkloric uses of the studied plants and provided evidence that tuber extracts of D. dumetorum and D. hirtiflora might indeed be potential sources of natural antioxidant and antimicrobial agents.
Key words: Dioscorea, antimicrobial activity, antioxidant activity, bioactive compounds.