Abstract: Different polyphenol extracts (crude methanol extract and its fractions soluble in ethyl acetate, chloroform, n-butanol and water) obtained from Hovenia acerba fruit stalks using organic solvents with different polarity were tested for their UV absorption characteristics in the range of 200－700 nm and polyphenol contents, and their antioxidant activity was assessed based on the ability to scavenge DPPH and ABTS free radicals and reduce ferric ions in vitro. The results indicated that liquid-liquid extraction was a successful method for separating polyphenols with different polarities. The crude extract and its different fractions had different spectral characteristics. A significant difference in total polyphenol content and antioxidant activity was observed among the crude extract and its different fractions. Four different fractions of the crude extract could be ranked in the following order: water-soluble fraction ＞ n-butanol-soluble fraction ＞ ethyl acetate-soluble fraction ＞ chloroform-soluble fraction. Therefore, polar polyphenols were dominant in Hovenia acerba fruit stalks.

Key words: Hovenia acerba fruit, polyphenol, separation, antioxidant activity in vitro