Antioxidative Potential of Pomegranate Peel Extract: In Vitro and In Vivo Studies

Abstract

Background/Aim: Due to the numerous beneficial effects of pomegranate that can be explained through its antioxidative effects, the aim of this study was to determine the antioxidant potential of pomegranate peel extract (PoPEx) pre-pared from pomegranate that was harvested in the south-east region of Herzegovina (Bosnia and Herzegovina), through in vitro and in vivo studies. Methods: In PoPEx total phenols, flavonoids, flavonols, flavan-3-ols and antho-cyanins content was determined, as well as several antioxidative assays, includ-ing 2,2 diphenyl-1-picrylhydrazyl assay (DPPH), 2,2'-azino bis(3-ethylbenzothi-azoline-6-sulphonic acid) assay (ABTS), iron (III)-2,4,6-tripyridyl-S-triazine complex assay (FRAP), reduction of copper(II) ions (CUPRAC) assay, Briggs-Rauscher oscillatory reactions, neutralisation of OH radicals and lipid peroxidation assay. In vivo studies were performed by administrating 100 mg/ kg of body weight of PoPEx to the rats by gavage for 7 days, after which the rats were euthanised and prooxidative parameters (thiobabrituric acid reactive substances-TBARS as an index of lipid peroxidation, nitrites-NO2, hydrogen peroxide-H2 O2 and superoxide anion radical O2-) were determined in plasma, as well as antioxidative parameters (superoxide dismutase-SOD, reduced gluta-thione-GSH and catalase-CAT) in erythrocyte lysates. Results: High content of phenolic compounds was found in PoPEx, which result-ed in high antioxidative potential in all in vitro tests performed. In vivo study showed that PoPEx administration caused a significant decrease in TBARS, NO2-, as well as an increase in reduced glutathione (p < 0.05) in comparison to the control group, while H2 O2 and O2 * showed a lowering trend and SOD and CAT showed an increasing trend in PoPEx group, but without statistical significance. Conclusion: PoPEx demonstrated high antioxidative capacity measured in vitro and in vivo and can be potentially used as a supplement treatment in the prevention of various inflammatory conditions.