Anthocyanins of Pithecellobium dulce (Roxb.) Benth. Fruit Associated with High Antioxidant and alpha-Glucosidase Inhibitory Activities

摘要

Red arils of Pithecellobium dulce fruit, commonly known as guamuchil, show high antioxidant (AOx) and alpha-glucosidase inhibitory (I alpha G) activities, which have been mainly associated with the content of unknown anthocyanins. In this study, the AOx (i.e., DPPH and ABTS as Trolox equivalents, mol TE/g) and I alpha G (as half-maximal inhibitory concentration, IC50, mg/mL) activities of the anthocyanin-rich fraction (ARF) obtained from red arils were contrasted with those of the methanol extract (ME), and the main ARF anthocyanins were characterized by HPLC-DAD-ESI-MS, GC-MS and H-1-NMR. The AOx and I alpha G values of the ARF (DPPH=597.8; ABTS=884.01; IG=0.06) were better than those of the ME (DPPH=41.5; ABTS=142.3; I alpha G=17.5); remarkably, the ARF IG value was about 42 times lower than that of acarbose. The main anthocyanins in ARF were pelargonidin 3-O-glucoside and cyanidin 3-O-glucoside. Thus, the consumption of red P. dulce arils could provide health benefits for prevention/treatment of chronic degenerative diseases such as diabetes.