Antioxidative Activity of Extracts from Hop (Humulus lupulus L.)

Abstract

Samples were extracted from hop (fresh and dried hop) by ethanol, methanol and ethyl acetate and antioxidative activity was assessed. Extract content, color, α-tocopherol content and absorption were also determined. The following results were obtained : Crude drug extract content in fresh and dried hop was 6.33 % and 7.17 % in the ethanol extract, 5.17 % and 6.16 % in the methanol extract and 2.74 % and 7.32 % in the ethyl acetate extract from 100 g of hop. α-Tocopherol content in 100 g of fresh or dried hop was 4.5 mg and 3.15 mg in the methanol extract and 4.10 mg or 4.20 mg in the ethyl acetate extract, none could be detected in the ethanol extract. The results of thin layer chromatography (solvent chloroform : ether : acetic acid = 97 : 2.3 : 0.5, vol/vol) indicated 5 fractions in the methanol extract and 2 fraction in the ethanol extract, and ethyl acetate extract, respectively.The strongest antioxidative activity from hop was noted for the dried hop methanol extract. Among the fractions in the methanol extract, fractions 1 and 5 showed strong activity.