Characterization of Flavonoids from Albizia amara Leaves and their Biological Activity on Microbes

Abstract

Phytochemical screening of methanol extract of leaves of Albizia Amara revealed the presence of secondary metabolites: saponins, alkaloids, tannins, glycosides and flavonoids. Powdered shade- dried leaves (1kg) of A. amara. were extracted with 95% ethanol at room temperature for 48 hours, The crude extract was suspended in water and partitioned with organic solvents in order of increasing polarity, petroleum ether, chloroform ethyl acetate and n-butanol, three compounds were isolated from n-butanol fraction. These compounds were isolated by chromatographic techniques and identified via spectroscopic tools: IR, UV, 1HNMR and Mass spectroscopy. The isolated compounds were tested for antimicrobial potential against four bacterial strains: Gram-positive (Staphylococus aureus and Bacillus subtilis), gram-negative (Pseudomonas aeruginosa and Escherichia coli) and two Fungal species (Candida albicans and Aspergillus niger). Agar well diffusion method was used to determine the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) at concentrations of 100 mg /ml to 6.25mg /ml. Compounds II and III showed significant antimicrobial activity at 100mg/ml and 50mg/ml. Compound I exhibited promising activity at these doses. The results of the Table 4 suggests that these flavonoids could serve as leads for further optimization.