Effects of Extraction Solvent on Polyphenolic Contents and Antioxidant Activities of Osmanthus fragrans' Seed

Effects of extraction solvent on the extraction yields of polyphenolic contents (total phenolic, flavonoid, anthocyanins and tannins contents) and antioxidant activitity of the Osmanthus fragrans' seed were examined for the first time. The extraction solvent included water and methanol, ethanol, acetone (30%, 70% and 100% v/v, respectively). The antioxidant activities of different solvent extractions from the O. fragrans' seed were evaluated using different evaluation methods (DPPH, ABTS, FRAP and HPSA). Results demonstrated that the extraction solvent influenced significantly the antioxidant activity and polyphenolic contents of the O. fragrans' seed. Mixed solvent extracts showed the higher polyphenolic contents and antioxidant capacity than absolute solvent extracts and water extracts. 30% methanol, 70% ethanol and 70% acetone were recommended solvents for extracting the phenolic antioxidants from the O. fragrans' seed. Correlation analysis suggested that phenolics and flavonoids might be the material base to antioxidant activity of the O. fragrans' seed. DPPH and ABTS might be the appropriate method to measure the antioxidant activities of the O. fragrans' seed.