Activity-Directed Fractionation & Isolation of Three Antimicrobial Compounds from Abrus Precatorius L. Seeds

Shortened Title: Anti-microbial activity of Isolates of Abrus precatorius. Summary The objective of the present investigation is to evaluate the antimicrobial potency of the various chromatographic fractions isolated from Abrus precatorius seeds against various pathogenic microbes. The seeds were powdered and extracted with methanol in soxhlet apparatus based on phytochemical screening. Three pure components were isolated by column chromatography and identified by thin layer chromatography and chemical analysis which were designated as F10, F11 * & F14 respectively. Disc diffusion method was employed to determine the antimicrobial effectiveness of test compounds I, II and III (F10, F11 * & F14) against 6 microbial species viz., Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa, Candida albicans and Aspergillus niger. The disc was saturated with 100 µl of each compound, allowed to dry and introduced on the upper layer of seeded agar plate. The plates were incubated overnight at 37°C. Microbial growth was determined by measuring the zonal inhibition diameters. Compound I showed maximum potency against gram positive B. subtilis (18 mm) in comparison with standard ciprofloxacin (26 mm), whereas the same compound was devoid of activity against the fungi A. niger (3 mm) & gram negative P. aeruginosa (2 mm) tested. Compound II was found to be sensitive against both the gram positive B. subtilis (16 mm) and the fungi C. albicans (14 mm). Compound III was found to exhibit maximum potency against the fungi C. albicans (23 mm) and gram positive S. aureus (15 mm). Among the 3 isolated components, Compound III was found to be very effective against one of the gram positive S. aureus and gram negative E.coli and all the fugal strains used.