In-vitro Antimycobacterial Activity of Selected Indian Medicinal Plants to Resistant Strains of Mycobacterium Tuberculosis

Tuberculosis (TB) remains a highly significant infection of microbial origin causing death of human in developing countries. The anti-tubercular drugs are less effective because of the emergence of multi-drug resistant strains and ineffective to extensively drug resistant strains of Mycobacterium tuberculosis. Plants are being an alternative source of antimicrobial compounds; the aim of this study was to investigate anti-mycobacterial potential of the few Indian medicinal plants and isolated compound from these to standard avirulent Mycobacterium tuberculosis H37Ra, standard virulent H37Rv and isoniazid resistant clinical isolates using Broth Microdilution Method. Methods and Results: Lyophilised ethanolic, aqueous and aqueous ethanolic extracts of four Indian medicinal plants viz. Coleus amboinicus, Glychirrhiza glabra, Pongamia pinnata and Terminalia chebula were screened for their in vitro antimycobacterial activity by Broth microdilution method (BMM) after 14 days of incubation at 37°C. The ethanolic extract of G. glabra was active against the tested strains of M. tuberculosis in primary screening with a MIC of 500μg/ml. The other extracts failed to exhibit inhibition at the tested concentrations. Glycyrrhizin a major and active constituent of the root of G. glabra was hence evaluated for its anitmycobacterial activity to the tested strains of M. tuberculosis. The isolated pure compound Glycyrrhizin exhibited a MIC value of 100μg/ml to the tested strains of M. tuberculosis. Conclusion: Our findings provide scientific support for ethno medical uses of Glycyrrhiza glabra to cure coughs and chest related ailments with the establishment of glycyrrhizin as a molecule for antimycobacterial activity and indicate a promising potential of this plant for the development of safer and efficacious anti-tuberculosis therapy. INTRODUCTION: Tuberculosis (TB) is an infection of microbial origin causing death of human in developing countries transmitted by inhalation of aerosolized droplets of Mycobacterium tuberculosis. It affects almost all the organs of the body, the lungs being most commonly involved. Due to the emergence of multi-drug resistant (MDR) strains the antitubercular drugs have become less effective and ineffective due to emergence of extensively drug resistant (XDR) strains of M. tuberculosis. QUICK RESPONSE CODE DOI: 10.13040/IJPSR.0975-8232.7(10).4130-33 Article can be accessed online on: www.ijpsr.com DOI link: http://dx.doi.org/10.13040/IJPSR.0975-8232.7 (10).4130-33 This has complicated the treatment and made TB more difficult to manage. Researchers around the world are increasingly turning their attention to traditional medicine in search of new and better antitubercular leads. Natural products play a significant role in the discovery and development of highly active antimycobacterial metabolites. The rhizome of Glycyrrhiza glabra Linn., commonly known as liquorice, is a reputed drug of Ayurveda. The rhizomes of G. glabra species have long been used worldwide as an herbal medicine and natural sweetener. Licorice is used to relieve ‘Vata’ and ‘Kapha’ inflammations, eye diseases, throat infections, peptic ulcers, arthritic conditions, and liver diseases in Indian Ayurveda system 1 . Aim: The aim of this study was to investigate antimycobacterial potential of the plants and plant