Antioxidant Activity and Bioacessibility of Polyphenols from Sea Buckthorn under in Vitro Simulated Gastro Intestinal Digestion

Abstract

The present study evaluates total phenolic content (TPC) and antioxidant activity of the Sea buckthorn berries extract under in vitro gastric intestinal and colonic batch fermentation. The TPC was determined using standard Folin-ciocalteau (FC) assay whereas antioxidant activity was determined using ABTS free radical scavenging activity. In this study, the digestion of Sea buckthorn extract was also compared with commercially available Sea buckthorn juice. It was observed that pure Sea buckthorn extract which was prepared in laboratory contained more TPC content throughout undigested (2.38 folds), gastric (2.11 folds) and small intestine phase (2.14 folds) of digestion. In case of antioxidant activity, the initial antioxidant content of pure extract and commercial juice was almost same but increase in pure extract in gastric (1.53 folds) and small intestine (2.33 folds) phase was observed over commercial juice. Though, in case of both pure extract and commercial juice increase in TPC and antioxidant activity was observed after gastric and small intestine phase. For colonic batch fermentation of pure Sea buckthorn extract and small intestine digested extract were lyophilized. Lyophilized sample (0.5%) Sea buckthorn pure extract and commercial juice were added to serum bottles containing basal media and fecal slurry. In case of digested Sea buckthorn extract an increase in TPC was observed up to 72 hrs after which it gradually declined. In case of undigested samples, sudden increase in TPC content was observed after 24 hrs which also further declined indicating that during initial stages of digestion, the phenolics are extracted from the juice or extract matrix followed by their degradation under longer incubations.