Structural and functional characterization of polyphenols isolated from acerola (Malpighia emarginata DC.) fruit

Two anthocyanins, cyanidin-3-alpha-O-rhamnoside (C3R) and pelargonidin-3-alpha-O-rhamnoside (P3R), and quercitrin (quercetin-3-alpha-O-rhamnoside), were isolated from acerola (Malpighia emarginata DC.) fruit. These polyphenols were evaluated based on the functional properties associated with diabetes mellitus or its complications, that is, on the radical scavenging activity and the inhibitory effect on both alpha-glucosidase and advanced glycation end product (AGE) formation. C3R and quercitrin revealed strong radical scavenging activity. While the inhibitory profiles of isolated polyphenols except quercitrin towards alpha-glucosidase activity were low, all polyphenols strongly inhibited AGE formation.