The antimicrobial effect of the leaf extract and fractions of Lupinus arboreus was investigated. The crude methanol extract (CME) of the dried leaves obtained by 48 h cold maceration was fractionated into n-hexane fraction (HEF), ethyl acetate fraction (EAF), and methanol fraction (MEF); and evaluated using modified agar-well diffusion method. The results showed that the extract and fractions at varying concentrations, exerted strong antimicrobial activity on some of the test organisms. However, a weak activity was observed on the tested fungi-Aspergillus niger and Candida albicans. Ethyl acetate fraction showed the highest activity on many organisms than extract and other fractions.

We planned to isolate the active constituents from methanol extract of Lupinus arboreus leaves. The crude methanol extract (CME) was fractionated into hexane, ethyl acetate and methanol fractions. The fractions were isolated from silica gel column chromatography, which were eluted with gradient mixtures. The isolated fractions were characterized by using flavonoid screening, IR, UV and NMR spectral analyses. The result of the phytochemical analysis and chromatography of the ethyl acetate fraction over silica gel lead to the isolation of a flavonol glycosides, and identified as tetrahydroxyflavone-3α-rhamnoside. Bioactivityguided result indicated tetrahydroxyflavone-3α-rhamnoside and imparts anti-inflammatory compound in this plant.