%0 Journal Article
%T Antimicrobial Property of Extracts of Indian Lichen against Human Pathogenic Bacteria
%A Priya Srivastava
%A D. K. Upreti
%A T. N. Dhole
%A Apurva K. Srivastava
%A Meghanand T. Nayak
%J Interdisciplinary Perspectives on Infectious Diseases
%D 2013
%I Hindawi Publishing Corporation
%R 10.1155/2013/709348
%X Context. Usnea ghattensis G. Awasthi (Usneaceae) endemic fruticose lichen found growing luxuriantly in Northern Western Ghats of India, it also contains Usnic acid as a major chemical and tested against some human pathogenic bacteria. Objective. To explore antimicrobial properties of Usnea ghattensis against some human pathogenic bacteria. Materials and Methods. The lichen was extracted in acetone, methanol, and ethanol. In vitro antimicrobial activity was tested initially by Kirby-Bauer technique of disc diffusion method and was confirmed by minimum inhibitory concentration using Broth microdilution method according to the NCCLS guidelines. Results. Ethanol extract was most effective against Bacillus cereus and Pseudomonas aeruginosa with a zone of inhibition 29.8 ¡À 0.6£¿mm and 12.3 ¡À 0.5£¿mm diameters at a concentration of 0.2£¿mg/mL. Acetone and methanol extract demonstrated almost similar activity against Staphylococcus aureus and the zone of inhibition was 24.6 ¡À 0.5 and 24.7 ¡À 0.4£¿mm. Only methanol extract was showing activity against Streptococcus faecalis with a 13.5 ¡À 0.8£¿mm zone. MIC value noted against Staphylococcus aureus and Streptococcus faecalis was 6.25£¿¦Ìg/mL and 25£¿¦Ìg/mL, whereas against Bacillus cereus and Pseudomonas aeruginosa, MIC calculated was 3.125£¿¦Ìg/mL and 200£¿¦Ìg/mL, respectively. Conclusion. The present study demonstrates the relatively higher activity of this lichen against not only gram (+) but significantly also against gram (£¿) bacteria. This indicates that this lichen might be a rich source of effective antimicrobial agents. 1. Introduction Medicinal plants are well-known natural sources for the treatment of various diseases since ancient times. Lichens are among the most fascinating organisms on this planet. Lichen is not a single organism the way most other living things are, but rather it is a combination of two organisms which live together intimately. The fungus forms a thallus or lichenized stroma that may contain characteristic secondary metabolites in all lichens [1]. Lichens are valuable plant resources and are used as medicines, food, fodder, dyes perfume, spice, and for miscellaneous purposes. The lichen flora is rather poor in the vicinity of industrial areas and big cities [2], as lichens are very sensitive to various air pollutions. Thus, these organisms are used as air pollution monitors [3]. The specific, even extreme, conditions of their existence, slow growth, and long duration (maximum lifetime spans to several thousand years) are consistent with their abundance in protective metabolites against different
%U http://www.hindawi.com/journals/ipid/2013/709348/