Polyphenolic composition, antiradical and hepatoprotective activities of bilberry and blackberry pomace extracts

Abstract

BACKGROUND: Considerable amounts of polyphenolic antioxidants remain in the press-cake during processing of berry fruits. OBJECTIVE: The aim of this study was to investigate polyphenolic profile, antiradical and hepatoprotective activities of wild bilberry (WBI) and blackberry cv. Čačanska bestrna (CBL) and cv. Thornfree (TBL) pomace extracts. METHODS: Polyphenolic profiles of berry pomace extracts were determined by HPLC. in vitro antiradical activities were confirmed with electron spin resonance (ESR) spectroscopy. In vivo antioxidant and hepatoprotective properties were evaluated by following activities of several enzymes and the levels of glutathione-GSH and thiobarbituric acid reactive substances. RESULTS: Protocatechuic acid (3.36–35.18 mg g -1 ) and gallic acid (9.57–31.98 mg g -1 ) were the most dominant phenolic compounds in WBI, CBL and TBL. Strongest scavenging activity on O 2 •- (EC 50 O2 = 60.21 mmol TE g -1 ) and OH • (EC 50 OH = 3.00 mmol TE g -1 ) were found for WBI and CBL pomace extracts, respectively. The best result in neutralizing oxidative stress induced by CCl 4 , was observed for 2 mL of berry pomace extracts kg -1 b.w. Simultaneous application of 0.1-2 mL berry pomace extracts kg -1 b.w. and CCl 4 returned GSHPx, CAT and GSH levels to physiological levels. CONCLUSIONS: Bilberry and blackberry pomace are a good source of bioactive compounds with potential application in supplements and functional food.