Prenylflavonols from the Leaves of Macaranga sampsonii

Four novel prenylflavonols, macaranones A—D (1—4), were isolated from the leaves of Macaranga sampsonii. Their structures were elucidated on the basis of spectroscopic data. Macaranones C (3) and D (4) represent first two examples of flavonols having an unusual peltogynoid skeleton which is formed from a 2′-geranylflavonol by cyclization between 3-OH and C-1″ of the 2′-geranyl substituent of the flavonol. Compounds 1—4 were evaluated for the cytotoxicity against several human cancer cell lines.