Antibacterial activity of seleced medicinal plants used by the tribal people.

Muthuswamy, M.; Prabuseenivasan; Kumar, V.

Biomedicine; 2012; 32; 199-206.

Abstract: Background: In traditional medical systems, plants have a major role in the treatment of various ailments and this has made the search for new medicines form plants which are used by the traditional practitioners. Still there is a growing interest to utilize plants or plant derived molecules to cure microbial infections. The present study is attempted to collect the selected ethnomedicinal plants form forest areas of Tirunelveli district in Western Ghats of Tamil Nadu, India and to evaluate their antibacterial activity against five bacterial strains.

Methods: The ethnomedicinal information was collected through questionnaire among the Kanikar and Paliyar tribal who are practicing traditional medicine in Tirunelveli district, Western Ghats region of Tamil Nadu. Crude n-Hexane and methanolic extract prepared from selected medicinal plants were tested against two gram positive bacteria (Staphylococcus aureus MTCC 7443 and Bacillus subtilis MTCC 7415) and three gram negative bacteria (Escherichia coli MTCC 7436, Klebsiella pneumoniae MTCC 7407 and Vibrio cholerae MTCC 3906) at 100 m g and 500 m g/ml concentration by disc diffusion method. MIC of crude methanol extract prepared from selected plants was also tested by adopting broth dilution method.

Results: There are 32 plant species belonging to 24 families which are used to cure fever, cold, cough and other respiratory problems were collected with the help of 25 tribal practitioners. The methanolic extract of 19 plants showed inhibitory activity against one or more bacterial strains only at 500 m g/disc concentration. N-hexane extract of all the plants showed no activity. In particular, the methanol extract of seven plants namely Ruta graveolens, Mukia maderaspatana, Terminalia chebula, Curculigo orchioides, Camellia sinensis, Cleome viscose and Rauvolfia serpentine were showed promising antibacterial activity against most of the tested strains. The MIC test results showed that the extracts from seven plants exhibited activity against at least one bacterial strain between 125 m g/ml to 175 m g/ml concentration.

Conclusion: Most of the plants used in traditional medicine are used as either single or mixed with other ingredients and taken as maceration, infusion or decoction. The present study ascertains the value of plants used in herbal treatment, which could be of considerable interest to the potential for discovery of antibacterial principles for the development of new drugs.

Keywords: Antibacterial activity, Ethinomedicine, Herbal drugs, plant extracts

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