DNA protection, antioxidant and xanthine oxidase inhibition activities of polyphenol-enriched fraction of Berberis integerrima Bunge fruits

Objective(s): The aim of this study was to prepare fraction and determine the biological activities of the polyphenol-enriched fraction of Berberis integerrima Bunge fruits. Materials and Methods: In this assay fraction was extracted by column chromatography, using Amberlite column as the stationary phase. Phenol and flavonoids in the extract and fraction were analyzed by high performance liquid chromatography (HPLC). DNA protection ability, antioxidant and xanthine oxidase inhibition capacities of this fraction were also examined. Results: Phenol and flavonoid content measurement and HPLC analyses of this fraction confirmed that phenol and flavonoids were increased in fraction in comparison to extract (before using Amberlite column). In antioxidant measurement assay, the trolox equivalent values were 1.05± 0.04 and 0.8±0.11 in oxygen radical absorbance capacity (ORAC) and the EC50 values for cellular antioxidant activity were 55.51±0.21 and 95.67±0.13 μg/ml for quercetin and the fraction, respectively. The xanthine oxidase inhibition percentages were 97.6±0.003 and 90.2 6±0.003 in 100 μg/ml concentration of fraction and vitamin C respectively. Comet assay analysis showed that this fraction protects human lymphocytes against H2O2-induced DNA damages at 12.5 to 100 μg/ml concentrations. Conclusion: This study suggests that Amberlite column as the stationary phase help to improve phenolic compound in separating fractions. The results showed that B. integerrima fruits are rich in phenolic compounds and they are potent antioxidants with protective effects on oxidative damages. They might be used as functional ingredients in food and supplements.