Abstract
Genus Bauhinia (Caesalpiniaceae) is used traditionally for the treatment of wounds, ulcers, diabetes, general pain, inflammation and infections. The aim of the study was to investigate the anti-inflammatory and cytotoxic activities of the bioactive fractions of the leaves of Bauhinia retusa and to identify the chemical constituents in these active fractions by different spectroscopic techniques. The anti-inflammatory activity of chloroform and ethyl acetate soluble fractions (Br-1 and Br-2) of B. retusa and isolated compounds was determined in terms of their ability to inhibit NF-kB and iNOS activity and to decrease oxidative stress in cellular systems. Their cytotoxicity was also determined against a set of 6 mammalian cell lines. Seven compounds were isolated from Br-1 and Br-2, namely methyl gallate, (1) ethyl gallate, (2) kaempferol, (3) quercetin, (4) kaempferol 3-O-alpha-L-rhamnoside, (5) quercetin 3-O-alpha-L-rhamnoside (6) and beta- sitosterol (7), all reported for the first time from this species. Br-1 and Br-2 were found to decrease oxidative stress and inhibit NF-kB and iNOS activities. Among the isolated compounds, 1-4 were more effective in decreasing oxidative stress and inhibiting iNOS activity than compounds 5-7. None of the compounds inhibited NF-kB. The Br-1 and Br-2 showed cytotoxicity towards KB, SK-OV-3 and LLC-PK1 cell lines. Compounds 1, 2 and 4 were toxic to LLC-PK1 cells. Phytochemical investigation of the leaves of Bauhinia retusa has led to the isolation of seven compounds. Some of which showed promising anti-inflammatory, antioxidant and cytotoxic effects. The reported anti-inflammatory properties of this plant could be attributed to the presence of these constituents.