Prenylated flavonoids from the root bark of Berchemia discolor, a Tanzanian medicinal plant.

Five new prenylated flavonoids (1-5) were isolated from the root bark of Berchemia discolor, collected in Tanzania, along with 10 known compounds, by bioactivity-guided fractionation. The structures of compounds 1-5 were elucidated using various spectroscopic techniques. Of these isolates, compound 4, and the known compounds nitidulin (6), amorphigenin (7), and dabinol (8), exhibited cytotoxic activity when evaluated against a small panel of human cancer cells. Nitidulin (6) was further tested in an in vivo hollow fiber assay and found to be active against LNCaP (human hormone-dependent prostate cancer) cells implanted intraperitoneally, at doses of 10, 20, and 40 mg/kg.