UPLC-Q-TOF-MS/MS identification, antioxidant, and alpha-glucosidase inhibition activities of three forms of phenolic compounds from Yemeni jujube fruit: In vitro and in silico investigations

Abstract

Jujube fruits have rich medicinal value due to their biological properties which are affected mainly by geographical locations. This study investigates the antioxidant properties of free fraction (FF), esterified fraction (EF), bound fraction (BF), and other metabolites prepared from dried Yemeni jujube fruit and compare to those previously reported in the literature. Results from UPLC-Q-TOF-MS/MS analysis showed that this fruit consists of a total of 33, 26, and 27 free, esterified, and bound compounds identified, respectively. In terms of ABTS, DPPH, FRAP, and H₂O₂ assays, the BF exhibited values 1.2, 1.3,1.3, and 1.4 times higher than those of the FF, and similarly, 1.8, 1.9,2.0, and 2.5 times higher than the EF. A similar trend was observed in the inhibition of α-glucosidase (α-Glu), where the BF was 1.6, and 2.4 times more effective compared to the FF and EF, respectively. In silico analysis showed that flavonoids, the key active compounds, had substantial α-glucosidase binding capacity. In the meat model, all fractions inhibited protein and lipid oxidation during storage, and the BF exhibited the highest antioxidant capacity. This study provides the first investigation of the structure of active compounds and their biological properties in Yemeni jujube fruit. Yemeni fruits can be utilized as natural antioxidants, and nutraceuticals in food preservation, and medicine respectively.