Local Medicinal Plants can give “Safety Net” against Tuberculosis?

AS Kumar, Seerreen & Sanjeet Kumar*
* Department of Botany, Ravenshaw University, Cuttack, India 
sanjeet.biotech@gmail.com

Tuberculosis or TB is a common, infectious disease caused by various strains of bacteria, usually Mycobacterium tuberculosis. Tuberculosis has been present in humans since antiquity at the latest. The earliest unambiguous detection of M. tuberculosis involves evidence of the disease in the remains of bison dated to approximately 17,000 years ago. However, whether tuberculosis originated in bovines, then was transferred to humans, or whether it diverged from a common ancestor, is currently unclear. A comparison of the genes of M. tuberculosis complex (MTBC) in humans to MTBC in animals suggests humans did not acquire MTBC from animals during animal domestication, as was previously believed. Both strains of the tuberculosis bacteria share a common ancestor, which could have infected humans as early as the Neolithic Revolution. Skeletal remains show prehistoric humans (4000 BC) had TB, and researchers have found tubercular decay in the spines of Egyptian mummies dating from 3000–2400 BC. Phthisis is a Greek word for consumption, an old term for pulmonary tuberculosis; around 460 BC, Hippocrates identified phthisis as the most widespread disease of the times.

It was said to involve fever and the coughing up of blood, which was almost always fatal. Genetic studies suggest TB was present in the Americas from about the year 100 AD. Tuberculosis typically attacks the lungs, but can also affect other parts of the body. It is spread through the air when people who have an active TB infection cough, sneeze, or otherwise transmit their saliva through the air. Most infections are asymptomatic and latent, but about one in ten latent infections eventually progresses to active disease which, if left untreated, kills more than 50% of those so infected. The classic symptoms of active TB infection are a chronic cough with blood-tinged sputum, fever, night sweats, and weight loss . Infection of other organs causes a wide range of symptoms. Treatment is difficult and requires administration of multiple antibiotics over a long period of time. The main cause of TB is Mycobacterium tuberculosis, a small, aerobic, non-motile bacillus. The high lipid content of this pathogen accounts for many of its unique clinical characteristics. It divides every 16 to 20 hours, which is an extremely slow rate compared with other bacteria, which usually divide in less than an hour. Mycobacteria have an outer membrane lipid bilayer. If a Gram stain is performed, MTB either stains very weakly "Gram-positive" or does not retain dye as a result of the high lipid and mycolic acid content of its cell wall. MTB can withstand weak disinfectants and survive in a dry state for weeks. In nature, the bacterium can grow only within the cells of a host organism, but M. tuberculosis can be cultured in the laboratory. Tuberculosis (TB) remains one of the most prevalent causes of death in developing countries, due to a single infectious bacterial agent called Mycobacterium tuberculosis (WHO, 1998). Currently, one third of the world’s population is infected with M. tuberculosis and each year there are 2 - 3 million deaths worldwide caused by the disease (Zumla et al., 1999). TB is a leading cause of death among people with human immunodeficiency virus (HIV). Individuals infected with HIV are very susceptible to TB and often develop this disease before other manifestations of AIDS become apparent (Grange and Davey, 1990; Lall and Meyer, 1999).

Today, strains of TB that are resistant to all major anti-TB drugs have emerged. The emergence of resistance to antimicrobials, though is a natural biological occurrence, has become an important public health issue in many developing countries as the treatment of TB requires the use of more expensive drugs for a longer treatment period. There is, therefore, an urgent need for new, inexpensive TB drugs which are more effective and with less side effects. Medicinal plants are an integral part of developing countries. plants have been used in traditional medicine to treat various ailments. Population groups at highest risk for poor nutrition are also at high risk for TB (Paras et al., 2006). Particularly, vitamins, alkaloids, terpinoids and polyphenols are important for proper functioning of immune system and detoxification. It has been reported that there is a high oxidative stress during early stages of TB and antioxidants such as green tea extract can play a vital role by reducing stress through adjuvant therapy (Guleria et al., 2003).

                                      India is one of the few countries in the world which has unique wealth of medicinal plants and vast traditional knowledge of the use of herbal medicine for the cure of various diseases (Gupta and Tandon, 2004; Sharma, 1998). India is represented by rich culture, traditions and natural biodiversity; and offer unique opportunity for the drug discovery researchers. (Raju Gautam, 2007). So far, few plants have been tested against mycobacterium. The increasing incidence of MDR- and XDR-TB worldwide, highlight the urgent need to search for newer anti-TB compounds/drugs. Therefore, the present study was carried out to check the antibacterial activity of aqueous and ethanoilc extracts of eight plants against M. tuberculosis H37Ra. Few plants have already reported to have anti-TB activity (Grange, 1996; Gupta and Chopra, 1954; Jain, 1993; Ratnakar and Murthy, 1996; Bruce, 1967; Gottshall et al., 1949; Reynolds, 1999). Naturally occurring pure compounds as well as extracts from higher and lower forms of plants, microorganisms and marine organisms have indicated that inhibitory activity against M. tuberculosis is widespread in nature. Many compounds isolated using preliminary functional assays have been provided from investigators interested in phytochemical biodiversity. Usually, their potential pharmaceutical worth remains unknown since data to show that these compounds are adversely affecting mycobacterial survival mechanisms in humans, or have been derived from medicinal plants are lacking (Adewole et al., 2004). Research studies for in vitro screening of plant remedies are important for validating the traditional use of herbal treatments, and for providing leads in the discovery of new active principles for possible future development as anti-TB drugs (McGawa et al., 2008). These studies also help in promoting the value of the India’s traditional medicine. Commonly used spice/beverage plants in south India like Zingiber officinale, Allium sativum, Allium cepa, Syzygium aromaticum, Cinnamomum verum, Camellia sinensis, Curcuma longa and Elettaria cardamomum were selected to test their activity against strains of M. tuberculosis H37Ra through microplate Alamar blue assay (MABA).Recently, there has been widespread interest in drugs derived from plants. This interest primarily stems from the belief that medicinal plants are safe and dependable, as opposed to synthetic drugs that are costly and have adverse effects (Stuffness and Douros, 1982). In the past years several reports and review articles appeared in the literature about medicinal plants and natural products with anti-mycobacterium activity (Okunade et al., 2004; Copp, 2003; Gautam et al., 2007). Over 350 natural products, mainly from plant species, have been screened for their antimycobacterial activities.

Table 1: Adverse effects of Anti-TB drugs (Vikrant, 2011)

Drug	Adverse effects
Isoniazid	Skin rash, hepatitis
Rifampicin	Abdominal pain, nausea, vomiting, hepatitis thrombocytopenic purpura
Pyrazinamide	Arthralgia, hepatitis
Streptomycin	Vestibular and auditory nerve damage, renal damage
Ethambutol	Retrobulbar neuritis, ocular side effects
Thioacetazone	Skin rash, Exfoliative dermatitis
Paraaminosalicylic acid	Anorexia, nausea, vomiting, hypersensitivity reactions
Kanamycin	Vertigo, auditory nerve damage, nephrotoxicity
Ethionamide	Diarrhoea, abdominal pain, hepatotoxicity

Common medicinal plants used for TB

Botanical Name

Aegle marmelos

Oroxylum indicum

Azardirachta indica

Cassia tora

Saccharum officinarum

Jatropha gassipifolia

Ziziphus oenoplia

Moringa oleifera

Jatropha curcas

Lasia spinosa

Amaranthus spinosus

Ficus hispida

Cyperus rotundus

Tribulus terrestris

Sida cordifolia

Acorus calamus

Piper  longum

Acalypha indica

Aloe vera

Lantana camara

study revealed that plants have different types of secondary metabolites which can fight against TB. Therefore need a proper documentation and conservation of common medicinal plants.