Biflavonoids with cytotoxic and antibacterial activity from Ochna macrocalyx

Six biflavonoid and related compounds were isolated from the ethanolic extract of Ochna macrocalyx bark. One is a new compound, the isoflavanone dimer dehydroxyhexaspermone C (1). Previously isolated compounds obtained from the bark are biisoflavonoid hexaspermone C (2), tetrahydrofuran derivative ochnone (3), furobenzopyran derivative cordigol (4), and biflavonoids calodenin B (5) and dihydrocalodenin B (6). Although 3 has already been isolated, its spectral data are presented here for the first time. isolated compounds were tested for cytotoxic activity on MCF-7 breast cancer cells using the MTT reduction assay method. Compound 5 showed cytotoxic activity (7 +/- 0.5 muM) and 6 showed moderate cytotoxicity (35 +/- 7 muM). In antibacterial assays performed using three strains of multi-drug resistant (mdr) Staphylococcus aureus (RN4220, XU212 and SA-1199-B) compounds 5 and in particular 6 showed strong antibacterial activity (MICs 5:64, 8,16 mug/mL 6:8, 8, 8 mug/mL, respectively). The ethanolic extract of the bark also showed NF-kappaB inhibitory activity.