Evaluation of the influence of in vitro human digestion simulation on the chemical composition and bioactivities of Ziziphus jujuba Mill.

Abstract

Fruit of Ziziphus jujuba Mill. are used as functional foods for centuries due to their rich content and bioactivities. Although in vitro antioxidant and hypoglycaemic activity of jujube fruit were investigated previously, the bioavailability phenomenon has been disregarded so far. For this study, 80\% ethanol extract of Ziziphus jujuba fruit (ZJE) was investigated for its in vitro hypoglycaemic and antioxidant potentials, before and after the interaction with simulated human digestion. DPPH scavenging activity, FRAP, CUPRAC, and TOAC assays were used for this purpose. Moreover, inhibition potentials of a-amylase and a-glucosidase enzymes and advanced glycation end products (AGE) were examined for the hypoglycaemic effect. Results indicated that ZJE showed significant antioxidant and dose dependent enzyme and AGE inhibition activity. Nonetheless, subsequent to simulated human digestion in vitro bioactivities of ZJE were significantly lowered for bioavailable fraction (IN). Protocatechuic acid (PA) (major phenolic compound of the fruit) contents of the extract and fractions were measured via HPTLC for more accurate understanding of the effects of human digestion and bioavailability profile.