Abstract

Aqueous extracts of 54 medicinal plants were evaluated for antibacterial activity against important human pathogenic and plant pathogenic bacteria by agar well diffusion method. Aqueous extracts of Combretum latifolium Bl., Persea macrantha (Nees) Kosterm., Vateria indica L. and Humboldtia brunonis Wall. recorded significant inhibitory activity against both human and plant pathogenic bacteria. These plants were further subjected to solvent extraction successively with petroleum spirit, chloroform, ethyl acetate and methanol based on increasing polarity to identify the suitable solvent for isolation of the antibacterial active principle. Ethyl acetate and methanol extracts of C. latifolium Bl. and V. indica L.significantly inhibited the important human pathogenic bacteria, including Escherichia coli, Salmonella typhi, Staphylococcus aureus and Bacillus cereus. Ethyl acetate extract of P. macrantha (Nees) Kosterm. and Humboldtia brunonis Wall. significantly inhibitedPseudomonas syringae, Xanthomonas oryzae pv. oryzae and Xanthomonas axonopoidispv. vesicatoria which are important plant pathogenic bacteria. Results of the present investigation suggests that C. latifoliumi Bl., P. macrantha (Nees) Kosterm., V. indica L. andH. brunonis Wall. are important candidate plants for further work on isolation and characterization of antibacterial active principle.

Key words: Bioprospecting, medicinal plants, antibacterial activity, Combretum latifoliumBl., Persea macrantha (Nees) Kosterm., Vateria indica L., Humboldtia brunonis Wall.