Two new prenylated isoflavones from Deguelia costata

Abstract Phytochemical investigation of the roots, leaves and stems of Deguelia costata resulted in the isolation of two new prenylated isoflavones, 5,5”-dihydroxy-4'-methoxy-6”,6”-dimethyl-4”,5”-dihydropyrano [2”,3”:7,8]isoflavone ( 1 ), and 5-hydroxy-4'-methoxy-5”-hydroxyisopropyl-4”,5”-dihydrofurano[2”,3”:7,8]isoflavone ( 2 ), together with nine known compounds, 4'-O-methylderrone ( 3 ), 4'-O-methylalpinumisoflavone ( 4 ); 5-hydroxy-3',4'-dimethoxy-2”,2”-dimethylpyrano[5”,6”:7,6]isoflavone ( 5 ), gancaonin M ( 6 ), robustin ( 7 ), isorobustin ( 8 ), scandenin ( 9 ), lupeol ( 10 ), and betulinic acid ( 11 ). The structures of 1 and 2 were determined by analyses of their spectroscopic data [ 1 H, 13 C NMR, HSQC and HMBC] and mass spectrometry. The cytotoxicity of 4'-methylderrone ( 3 ), scandenin ( 9 ), lupeol ( 10 ), and betulinic acid ( 11 ) were evaluated on C6 glioma cells. Among them, betulinic acid ( 11 ) presented a cytotoxic effect on rat C6 glioma cells with an IC 50 value of 38.0 μM. The total flavonoid content of dichloromethane extract from leaves, the most enriched in isoflavones, was obtained using the AlCl 3 method (80.07 ± 1.55 μg Quercetin g −1 dry extract). This new study reveals the potential of D. costata as a source of new isoflavones, as well as the promising cytotoxic effect of betulinic acid on C6 glioma cells.