Comparison of five solvents in the extraction of phenolic antioxidants from pomegranate (Punica granatum L.) peel

Background:  Pomegranate peels are rich in bioactive compounds and could be an alternative natural source such as antioxidants.  Aims:   The aim of the present study was to assess the abilities of five solvents to extract phenolic antioxidants from pomegranate peels. Methods and Material:  Pomegranate peels powder was subjected to extraction and the extraction yield was compared. The total phenolic, flavonoid, condensed and hydrolysable tannins contents were analyzed. The antioxidant activity of the extracts was evaluated by two methods (DPPH* and ABTS•+ scavenging capacities) and results were then compared.  Results:  Results showed that the mixture methanol/water (50:50) allowed higher extraction yield (37.33 ± 5.3%) than the others solvents (p <0.05). Further, the total phenolic, flavonoid and condensed tannins contents were the highest in mixture water/methanol (50:50) extract. Phenolic antioxidants showed a distinct reducing capacity and a high DPPH* inhibition values were recorded for all extracts with no significant differences (p >0.05) between ethanol and mixture water/methanol (50:50) extracts. All extracts exhibited high inhibition against ABTS•+ but with a considerable variation. Phenolic content and antioxidant activities were well positively correlated with each other.  Conclusions:   Our findings revealed that the choice of the extracting solvent affects considerably the extraction of phenolic antioxidants from pomegranate peels.