Minor Prenylated Flavonoids from the Twigs of Macarangaadenantha and Their Cytotoxic Activity.

Three new minor prenylated flavonoids, named macadenanthins A-C (1-3), together with three known ones (4-6), were isolated from the twigs of Macaranga adenantha. Their structures were elucidated on the basis of extensive spectroscopic analysis including NMR, UV and MS. The prenyl moieties in compounds 1-3 were further modified by cyclization and hydroxylation. The new compounds were tested for their cytotoxicity against four cancer cell lines (MCF-7, Hep G2, Hela and P388) and showed IC50 values in the range of 13.76-22.27 μM.