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 microM) and 6 showed moderate cytotoxicity (35 +/- 7 microM). 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 microg/mL 6 : 8, 8, 8 microg/mL, respectively). The ethanolic extract of the bark also showed NF-kappaB inhibitory activity.