Antiglycation Activity and LC-MS/MS-Based Metabolomic Annotation of <i>Psidium cattleianum</i> (Myrtaceae) Fruit Peels

Psidium cattleianum (Myrtaceae) is a fruit with high nutritional and pharmaceutical value. This study aimed to evaluate the antiglycation and antioxidant activities of P. cattleianum peels and pulps, annotating the possible compounds responsible for these activities. The peels and pulps were separately extracted with ethyl acetate and methanol. Antiglycation activity was estimated by the inhibition of the glycation reaction. The ABTS•+ radical reduction assay and the peroxyl radical (ROO•) reduction assay were applied to evaluate antioxidant activity. In both methods, the methanolic extracts of the fruit peels exhibited higher antioxidant capacity, with EC50 values of 38.26 ± 2.51 μg mL– 1 for the ABTS•+ assay and 31.92 ± 0.94 μg mL– 1 for the ROO• assay. The acetylated and methanolic extracts of the peels exhibited high inhibition of the glycation reaction (34.2% and 41.1%, respectively). Given their high activity, the methanolic extracts of the peels were fractionated and analyzed by LC-MS/MS. The annotations on the methanolic fraction suggest the presence of flavonoids and anthocyanins responsible for antioxidant and antiglycation activity.