RESUMEN
Basing on chromatographic separation techniques, fifteen aglycones (1-15), including two new anthraquinone aglycones (1, 2) and thirteen known compounds (3-15), were isolated from the small polar fraction of Cassia obtusefolia (petroleum ether extract). Structural elucidations were performed by 1D/2D NMR spectroscopy and mass spectrometry. The in vitro antioxidant and α-glucosidase inhibitory activities of these fifteen compounds were determined. Except compounds 12 (IC50 3.03⯱â¯0.31⯵g/mL, stronger than ascorbic acid, which IC50 was 6.48⯱â¯2.30⯵g/mL) and 13 (IC50 78.40⯱â¯2.39⯵g/mL), the free radical scavenging capacities of other compounds were weak. Compounds 4, 5, 6 and 13 exhibited inhibitory activities on α-glucosidase with IC50 values of 50.60⯱â¯1.10, 22.57⯱â¯0.07, 60.09⯱â¯1.40, and 80.01⯱â¯2.66⯵g/mL separately, however, all the α-glucosidase inhibitory activities were weaker than positive control (acarbose).