Macaflavanones A-G, Prenylated Flavanones from the Leaves of Macaranga tanarius

Phytochemical investigation of leaves of Macaranga tanarius resulted in the isolation of seven new prenylated flavanones, macaflavanones A-G (1-7), along with two known compounds, nymphaeol C (9) and the diterpene kolavenol. The structures of the new compounds were elucidated by means of a combination of spectroscopic methods and chemical conversion. The absolute structure of tanariflavanone B (8), isolated from the title plant, was also resolved. The cytotoxic activities of isolated flavanones were assayed using two cell lines, with macaflavanone G (7) being the most active compound in each case.