New α-glucosidase inhibiting anthracenone from the barks of Harungana madagascariensis Lam

Two new 10-hydroxy-9(10H)-anthracenone, madagascenone A (1) and B (2), were isolated from the barks of Harungana madagascariensis Lam. The structures of the compounds were determined using 1D- and 2D-NMR and mass spectroscopic techniques. Both of the compounds showed an in vitro α-glucosidase inhibition with IC50 = 69.9±4.21 and 122.3±1.13 μM, respectively, more potent than the standard acarbose (IC50 = 840 ± 1.23 μM).