Efficacy of different solvent extracts of Aristolochia krisagathra and Thottea ponmudiana for potential antimicrobial activity

Objective: To investigate the antimicrobial potentiality of two medicinal plants namely Aristolochia krisagathra and Thottea ponmudiana against 12 bacteria and 2 fungi. Methods: The Staphylococcus aureus (S. aureus) (MTCC 96), Staphylococcus epidermidis (S. epidermidis) (MTCC 435), Bacillus subtilis (B. subtilis) (MTCC 121), Escherichia coli (E. coli) (MTCC 739), Klebsiella pneumoniae (K. pneumoniae) (MTCC 432), Proteus vulgaris (P. vulgaris) (MTCC 742), Proteus mirabilis (P. mirabilis) (MTCC 425), Salmonella paratyphi A (S. paratyphi A) (MTCC 735), Salmonella paratyphi B (S. paratyphi B) (clinical isolate), Salmonella typhimurium (S. typhimurium) (MTCC 98), Shigella flexneri (S. flexneri) (MTCC 1457), Vibrio parahaemolyticus (V. parahaemolyticus) (MTCC 451), Candida albicans (C. albicans) (MTCC 183) and Cryptococcus neoformans (C. neoformans) (clinical isolate) were originally obtained from Microbial Type Culture Collection Centre (MTCC), Institute of Microbial Technology, Chandigarh, India. The mentioned plants of A. krisagathra and T. ponmudiana were extracted with methanol and petroleum ether extracts and its antimicrobial property was tested by using disc diffusion and broth dilution methods. Results: Antimicrobial potentiality of methanolic and petroleum ether extract of A. krisagathra and T. ponmudiana was evaluated against microorganisms, the highest inhibitory activity was observed against S. aureus (22.8 mm), S. epidermidis and B. subtilis (17.0 mm) in methanolic extract, where as petroleum ether extract showed moderate inhibitory activity against S. epidermidis (17.4 mm) and B. subtilis (16.2 mm). According to broth dilution method, the methanolic plant extract of A. krisagathra showed the highest Minimal Inhibitory Concentration (MIC) values against S. aureus (128 ?g/mL), S. epidermidis and B. subtilis (256 ?g/mL), whereas the petroleum ether extract of A. krisagathra showed the moderate MIC values against B. subtilis (256 ?g/mL) and S. epidermidis (512 ?g/mL) with significant inhibitory activity. Methanolic extract of T. ponmudiana showed maximum inhibitory activity against S. epidermidis (19.2 mm) and S. aureus (15.8 mm). None of the microbial strain inhibited by petroleum ether extract. The methanolic extract of T. ponmudiana has been effective against S. epidermidis (256 ?g/mL) and S. aureus (512?g/mL). Conclusion: The present result revealed that the methanolic extract of both the plants possesses significant antimicrobial activity when compared to petroleum ether extract.