Abstract: An L9 (34) orthogonal array design was employed to optimize the extraction of total flavonoids from bayberry (Myrica rubra Sieb. et Zucc.) leaves. The in vitro antioxidant activity of total flavonoids extracted was evaluated by determining their scavenging capacity against hydroxyl radicals and superoxide anions. The optimum extraction conditions were determined as follows: 65% aqueous ethanol solution as extraction solvent at a material/liquid ratio of 1:30 (g/mL) for triple repeated extractions for 1.5 h each time and the extraction rate is 3.34%. Total flavonoids from bayberry leaves could strongly scavenge hydroxyl and superoxide anion free radicals, thus being a powerful natural antioxidant.

Key words: bayberry leaves, total flavonoids, extraction conditions, antioxidant activity