Extract from Eugenia punicifolia is an antioxidant and inhibits enzymes related to metabolic syndrome.

The present study aimed to investigate in vitro biological activities of extract of Eugenia punicifolia leaves (EEP), emphasizing the inhibitory activity of enzymes related to metabolic syndrome and its antioxidant effects. The antioxidant activity was analyzed by free radicals scavengers in vitro assays: DPPH·, ABTS(·+), O2(·−), and NO· and a cell-based assay. EEP were tested in inhibitory colorimetric assays using α-amylase, α-glucosidase, xanthine oxidase, and pancreatic lipase enzymes. The EEP exhibited activity in ABTS(·+), DPPH·, and O2(·−) scavenger (IC50 = 10.5 ± 1.2, 28.84 ± 0.54, and 38.12 ± 2.6 μg/mL), respectively. EEP did not show cytotoxic effects, and it showed antioxidant activity in cells in a concentration-dependent manner. EEP exhibited inhibition of α-amylase, α-glucosidase, and xanthine oxidase activities in vitro assays (IC50 = 122.8 ± 6.3; 2.9 ± 0.1; 23.5 ± 2.6), respectively; however, EEP did not inhibit the lipase activity. The findings supported that extract of E. punicifolia leaves is a natural antioxidant and inhibitor of enzymes, such as α-amylase, α-glucosidase, and xanthine oxidase, which can result in a reduction in the carbohydrate absorption rate and decrease of risks factors of cardiovascular disease, thereby providing a novel dietary opportunity for the prevention of metabolic syndrome.