An ethyl acetate extract derived from the seeds of the medicinal and food plant Casimiroa edulis
inhibited mutagenicity induced by 7,12-dimethylbenz[a]anthracene (DMBA) with Salmonella
typhimurium strain TM677. It also showed complete inhibition of DMBA-induced preneoplastic
lesions with an in vitro mouse mammary gland organ culture system at a concentration of 10 μg/mL. Bioassay-guided phytochemical investigation of this extract using antimutagenicity as a monitor
led to the isolation of four furocoumarins, constituted by the known compounds phellopterin (1)
and isopimpinellin (2) and the novel compounds (R,S)-5-methoxy-8-[(6,7-dihydroxy-3,7-dimethyl-2-octenyl)oxy]psoralen (3) and (R,S)-8-[(6,7-dihydroxy-3,7-dimethyl-2-octenyl)oxy]psoralen (4). Four
known alkaloids, casimiroin (5), 4-methoxy-1-methyl-2(1H)-quinolinone (6), 5-hydroxy-1-methyl-2-phenyl-4-quinolone (7), and γ-fagarine (8), and two known flavonoids, zapotin (9) and 5,6,2‘-trimethoxyflavone (10), were also isolated. Of these isolates, compounds 3 and 5 showed the most
potent antimutagenic effects in the forward mutagen assay utilizing S. typhimurium strain TM677,
whereas casimiroin (5) and 5,6,2‘-trimethoxyflavone (10) significantly inhibited the formation of
DMBA-induced preneoplastic lesions in mouse mammary gland organ culture.
Keywords: Casimiroa edulis; Rutaceae; furocoumarins; (R,S)-5-methoxy-8-[(6,7-dihydroxy-3,7-dimethyl-2-octenyl)oxy]psoralen; (R,S)-8-[(6,7-dihydroxy-3,7-dimethyl-2-octenyl)oxy]psoralen; alkaloids; flavonoids; antimutagens; mouse mammary organ culture assay; cancer chemoprevention
