Anti-cancer activity of compounds from Bauhinia strychnifolia stem

Abstract

Ethnopharmacological relevanceThe stem and root of Bauhinia strychnifolia Craib (Fabaceae family) have been traditionally used in Thailand to treat fever, alcoholic toxication, allergy and cancer. An EtOH extract of Bauhinia strychnifolia showed good inhibitory activity against several cancer cell lines including HT-29, HeLa, MCF-7 and KB. As there has been no previous reports on chemical constituents of Bauhinia strychnifolia, this study is aimed to isolate the pure compounds with anti-cancer activity. Materials and methodsFive pure compounds were isolated from EtOH extract of Bauhinia strychnifolia stem using silica gel, dianion HP-20 and sephadex LH-20 column chromatography and were tested for their cytotoxic effects against HT-29, HeLa, MCF-7 and KB cell lines using the Sulforhodamine B (SRB) assay. ResultsAmong five compounds, 3,5,7,3′,5′-pentahydroxyflavanonol-3-O-α-l-rhamnopyranoside (2) possessed very potent activity against KB (IC50=0.00054μg/mL), HT-29 (IC50=0.00217μg/mL), MCF-7 (IC50=0.0585μg/mL) and HeLa cells (IC50=0.0692μg/mL). 3,5,7-Trihydroxychromone-3-O-α-l-rhamnopyranoside (3) also showed good activity against HT-29 (IC50=0.02366μg/mL), KB (IC50=0.0412μg/mL) and MCF-7 (IC50=0.297μg/mL), respectively. The activity of 2 (IC50=0.00054μg/mL) against KB cell was ten times higher than that of the positive control, Camptothecin (anti-cancer drug, IC50=0.0057μg/mL). All compounds did not show any cytotoxicity with normal cells at the concentration of 1μg/mL. ConclusionThis is the first report of compounds 2 and 3 on anti-cancer activity and based on the anti-cancer activity of extracts and pure compounds isolated from Bauhinia strychnifolia stem, it might be suggested that this plant could be useful for treatment of cancer.