Phenolic, non-phenolic compounds and antioxidant activity of pomegranate flower, leaf and bark extracts of four Tunisian cultivars

The aim of this work was to investigate phenolic and non-phenolic content and to determine the antioxidant activity in pomegranate flowers, leaves and barks among four Tunisian cultivars. The highest amounts of poylphenol compounds were recorded in Tounsi flower and Gabsi leaf extracts (218.64 and 131.91 mg/g of dry weight (DW), respectively). However, bark extracts showed relatively low proportions of phenolics but exhibited high concentrations of carotenoids. By measuring the antioxidant activity of the studied samples, the reducing power was correlated with phenolic compounds (r = 0.760; p < 0.01). The highest concentrations were recorded in Gabsi leaves and Chelfi flowers (254.25 and 140.63 mg/ml, respectively). 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity was correlated with total carotenoids content (r = 0.733; p < 0.01). These results suggest that the reducing power of our samples is mainly provided by phenolic compounds whereas non phenolic compounds are mainly contributing to the scavenging activity in the flowering period of pomegranate tree.