Antioxidant Activity of Pericarp Extract from Different Varieties of Pomegranate Fruit

The pomegranate Punicagranatum fruit pericarp, contain polyphenolic compounds including alpha and beta punicalagins and ellagic acid, which exhibit remarkable antioxidant activities. The aim of this study was to purify and quantify the phenolic components from different varieties of Pomegranate Pericarp Extracts (PPEs) and determine their antioxidant properties. Methanolic and aqueous extracts of four pomegranate cultivars (Shahvar, Siahsorfeh, Torshsabz and Abdorahimkhany, from Shiraz, Iran) were prepared and total phenolic content of PPEs was determined. PPE components were further purified by XAD-16 column chromatography followed by LH- 20 gel filtration. The eluted components were subjected to HPLC analysis to differentiate and quantify polyphenolic compounds. Antioxidant activity was measured using DPPH assay. The result revealed significant difference in total phenolic contents and phenolic components in four cultivars. Total phenolic content in methanolic PPE was significantly (P< 0.05) higher than aqueous extracts. Shahvar cultivar had the highest total phenols (11.72±0.01 mg mL-1 in water, 17.7±0.12 mg mL-1 in methanol) and exhibited the most antioxidant property among cultivars. Analysis of components of Shahvar PPE by HPLC showed that proportions of different phenolic components were alpha punicalagin (28.34±2.12%), beta punicalagin (39.75±2.14%) and ellagic acid (3.49±0.93%). Antioxidant activity of alpha punicalagin, beta punicalagin, punicalagin (sum of alpha+beta) and ellagic acid was 50.8, 60.5, 56, and 27%, respectively. Taken together, these results indicate that PPE of Shahvar cultivar is an excellent source of natural antioxidants and can potentially replace the current synthetic antioxidants in food and pharmaceutical industries.