Phenolic content and antioxidant capacity of various solvent extracts from seabuckthorn (Hippophae rhamnoides L.) fruit pulp, seeds, leaves and stem bark

The outcome of various solvent extraction (water, methanol, acidic 50% methanol, 70% acetone, acidic 50% methanol followed by 70% acetone) on the total phenolic content (TPC) and antioxidant capacity of fruit pulp, seeds, leaves and stem bark of seabuckthorn (Hippophae rhamnoides L.) was investigated. The seabuckthorn extracts possess high phenolic content, 1666–13769 mg GAE/100 g d.w. The mean TPC was found highest in seeds (11148) followed by stem bark (10469), leaves (6330) and pulp (3579 mg GAE/100 g d.w.). In general, the 70% acetone and acidic 50% methanol followed by 70% acetone extracts was found to contain significantly higher TPC than those obtained in other extracting solvents. Antioxidant capacity in terms of IC50 value of pulp (3.39 mg ml−1) was up to 7.8 times higher than those reported for stem bark (0.43 mg ml−1) and up to 2.4 times higher than those found in seeds (1.4 mg ml−1). Further, antioxidant capacity by FRAP assay showed that the stem bark possess maximum antioxidant capacity (16.83) followed by seeds (15.26), leaves (12.73) and pulp (12.61), all as mM FeSO4. Significant correlation was found between TPC and antioxidant capacity by DPPH and FRAP assays