Xanthones from Calophyllum Polyanthum Wallich ex Choisy with CYP1 Enzymes Inhibitory Activity

Three new xanthone compounds, 1,3,5-trihydroxy-2-(2-hydroxy-3-methylbut-3-enyl)-4-(3-methylbut-2-enyl)xanthone (1), toxyloxanthone E (2), dehydrocycloguanandin B (3) along with 15 known xanthones (4-18) were isolated from the aerial parts of Calophyllum polyanthum Wall. ex Choisy. Their structures were fully characterised using spectroscopic data, as well as comparison with the previous literature data. All isolated compounds had inhibitory effects against CYP1A1, CYP1A2 and CYP1B1 enzymes at working concentration of 10 μM, 1 μM and 10 μM, respectively. Among them, compounds 10, 11, and 12 exhibited better CYP1A2 enzyme inhibitory effects than that of the positive control α-naphthoflavone, with 51.05 %, 56.82 % and 44.93 % inhibition, respectively.