In vitro antidiabetic potential of the fruits of Crataegus pinnatifida

In an attempt to develop alternative medicine for the treatment of diabetes and related complications, the antidiabetic potential of the fruits of Crataegus pinnatifida was evaluated. The antidiabetic potential of the methanol (MeOH) extract as well as different solvent soluble fractions of the fruits of C. pinnatifida was evaluated via α-glucosidase, protein tyrosine phosphatase 1B (PTP1B), rat lens aldose reductase (RLAR), and advanced glycation end products (AGEs) formation inhibitory assays. The MeOH extract showed potent inhibitory activity against α-glucosidase, PTP1B, and AGEs formation with IC₅₀ values of 122.11, 3.66 and 65.83 μg/ml respectively, while it showed moderate inhibitory activity against RLAR with the IC₅₀ value of 160.54 μg/ml. Among different fractions, the ethyl acetate (EtOAc) and the dichloromethane (CH₂Cl₂) fractions were found as active fractions exhibiting potential α-glucosidase, PTP1B, RLAR inhibitory, and AGEs formation inhibitory activities. Seven compounds including hyperoside, chlorogenic acid, ursolic acid, oleanolic acid, 3-epicorosolic acid, β-sitosterol, β-sitosterol glucoside were isolated from these two fractions. 3-Epicorosolic acid showed both potent α-glucosidase and PTP1B inhibitory activities with IC₅₀ values of 30.18 and 4.08 μg/ml respectively. Moreover, kinetic study revealed that 3-epicorosolic acid showed mixed type inhibition against PTP1B, while it showed uncompetitive inhibition against α-glucosidase. Therefore, these results suggest that the fruits of C. pinnatifida and its constituents have potential antidiabetic activity which might be used as a functional food for the treatment of diabetes and associated complications.