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.