Antioxidant action and enzyme activity modulation by bioaccessible polyphenols from jambolan (Syzygium cumini (L.) Skeels)

Jambolan is rich in antioxidant polyphenols; however, the bioactivity of these compounds remains poorly investigated. We compared changes in polyphenols and antioxidant capacity by ABTS and FRAP assays of jambolan pulp during in vitro digestion and chemical extraction and evaluated the effects of these changes on oxidative stress in wild and mutant Saccharomyces cerevisiae. Digestion and chemical extraction were performed with enzyme saline solutions, deionized water, and 50% (v/v) aqueous acetone solution. Caffeic, quinic, gallic, and ellagic acids, isomers of myricetin, catechin, and anthocyanins are bioaccessible during gastric digestion. In the duodenum, flavonoids and proanthocyanidins remained stable when the pH changed from acidic to neutral/alkaline, whereas anthocyanins were degraded when exposed to pH 7. In the colon, anthocyanins were not identified. The antioxidant activity of bioaccessible fractions is correlated with non-anthocyanin flavonoids and proanthocyanidins, reflected in the modulation of antioxidant enzymes of S. cerevisiae. The digestion process favors the release of bio-polyphenols from jambolan with preventive, scavenger, and reparative antioxidant action. They also stimulate the production and activity of Sod and Cat, strengthening the endogenous antioxidant system.