Abstract: α-Glucosidase inhibitory activity of leaves of Chaenomeles speciosa (sweet) Nakai collected in different months was evaluated in vitro. Different extracts from the leaves of C.speciosa collected in March and July all showed α-glucosidase inhibitory activity,among which ethyl acetate extract of leaves collected in July (IC₅₀=47.27 μg/mL) showed the highest  α-glucosidase inhibitory activity,and it was far higher than that of acarbose (IC₅₀=1213.38 μg/mL).Ethyl acetate extract and n-butanol extract of leaves collected in July were higher than that of corresponding extract of leaves collected in March, but petroleum ether extract of leaves collected in July was lower than that of petroleum ether extract of leaves collected in March,and they were all higher than that of acarbose.In addition,the α-glucosidase inhibitory activities of different extracts were all shown in dose-dependent manner.

Key words: Chaenomeles speciosa  , (sweet) Nakai, &alpha, -glucosidase, inhibitory activity