Antitumor activity of biflavonoids from Ouratea and Luxemburgia on human cancer cell lines

The biflavones 7,7"-dimethyllanaraflavone (1), agathisflavone (2), and 7"-methylagathisflavone (3) isolated from the leaves of Ouratea hexasperma and luxenchalcone (4) isolated from the leaves and branches of Luxemburgia octandra, as well as a mixture of 7,7"-dimethyllanaraflavone and 7"-methylagathisflavone, were assayed against HT-29 colon adenocarcinoma, NCI-H460 non-small cell lung carcinoma, MCF-7 breast cancer cell, OVCAR-3 ovarian adenocarcinoma cells, and RXF-393 renal cell carcinoma. The results show significant activities, particularly for 7,7"-dimethyllanaraflavone ([C, 0.77 +/- 0.08, 2.42 +/- 0.22, and 2.59 +/- 0.32 mu g/ml for NCI-H460, MCF-7, and OVCAR-3, respectively), and for 7"-methylagathisflavone (IC50 values of 4 mu g/ml). Luxenchalcone revealed significant cytotoxicity on the five cell lines tested.