Abstract: An aqueous two-phase system composed of 24% PEG400 and 15% Na2SO4 was used to extract total flavonoids from the crude ethanol extract of Actinidia kolomikta leaves. The effects of crude extract concentration, KCl amount, pH and extraction temperature on the extraction efficiency of total flavonoids were explored by one-factor-at-a-time and orthogonal array design methods. The results showed that crude extract concentration and pH were major affecting factors and KCl, and extraction temperature exhibited less effect on the extraction efficiency of total flavonoids. The optimal aqueous two-phase extraction conditions were crude extract concentration of C0, KCl amount of 2%, pH of 9 and extraction temperature of 25 ℃. Under the optimal extraction conditions, total flavonoids from Actinidia kolomikta leaves was mainly distributed in the upper phase with a distribution coefficient of 24.31 and an extraction rate of 96.90%. Therefore, this method can provide a simple, convenient, economical and highly efficient strategy for the extraction of total flavonoids.

Key words: aqueous two-phase system, extraction and purification, Actinidia kolomikta leaves, flavonoids