ABSTRACT

Postprandial hyperglycemia is an early effect of type 2 diabetes and one of primary anti?diabetic targets. Treatment of postprandial hyperglycemia can be achieved by inhibiting intestinal ??amylase and ?-glucosidase, the key enzyme for starch digestion and further glucose absorption. This study evaluated the anti-diabetic potential of guava leaf by determining their anti?postprandial hyperglycemic activities in vivo and in vitro. Ethanolic extract of the leaves of Psidium guajava was orally tested at doses of 400 mg/kg body weight for evaluating the hypoglycemic effect in nomal and alloxan monohydrate induced diabetic mice. The results proved that diabetic mice treated with this plant extracts showed significant (P<0.05) reduction of the blood glucose to levels comparable to that of the non-diabetic control and those treated with gliclazide (standard drug). Similarly, there were significant changes in body weight in ethanolic extract treated diabetic animals, when compared with the diabetic control and normal animals. Finally, ethanolic plant extracts in this study showed no acute toxicity on healthy. The inhibition of ?-amylase and ?-glucosidase activity of aqueous, methanol and butanol extracts were carried out in vitro. The result demonstrated that these guava leaf extracts exerted significant inhibition and specific on intestinal ?-amylase and ??glucosidases activities. In conclusion, this study proved that guava extracts selectively and significantly inhibits intestinal ??amylase and ?-glucosidase and suppresses postprandial hyperglycemia in diabetic mice. The anti-postprandial hyperglycemic activities demonstrated on the tested guava extract therefore suggest a potential for utilizing guava leaf-derived bioactive compounds in management of diabetes.

Keywords: Psidium guajava L., diabetes mellitus, hypoglycemic, ?-amylase, ?-glucosidase

Title: Evaluation of antidiabetic activity of guava leaf (Psidium guajava L.)

ToM T?T

Tang d??ng huy?t sau b?a an la v?n d? kho ki?m soat c?a b?nh ti?u d??ng type 2 va do c?ng la m?c tieu chinh c?a ki?m soat b?nh. D??ng huy?t sau b?a an d??c ki?m soat b?ng cach ?c ch? enzyme tieu hoa tinh b?t va h?p thu glucose nh? enzyme ?-amylase va ?-glucosidase. Nghien c?u nay danh gia hi?u qu? di?u tr? ti?u d??ng c?a la ?i b?ng cach kh?o sat ho?t d?ng khang l?i s? tang d??ng huy?t sau b?a an in vivo va in vitro. Cao ethanol la ?i d??c s? d?ng li?u 400 mg/kg tr?ng l??ng cho chu?t b?nh ti?u d??ng d??c gay b?nh b?ng alloxan monohydrate va chu?t binh th??ng u?ng. K?t qu? ch?ng minh r?ng cao ethanol la ?i co kh? nang h? d??ng huy?t m?t cach co y ngh?a th?ng ke (P<0,05) so v?i nhom chu?t b?nh ti?u d??ng khong d??c u?ng cao chi?t la ?i va t??ng d??ng v?i thu?c di?u tr? ti?u d??ng gliclazide. K?t qu? thi nghi?m c?ng ch?ng minh cao ethanol la ?i co th? c?i thi?n tr?ng l??ng chu?t b?nh ti?u d??ng m?t cach co y ngh?a th?ng ke (P<0,05) va cao chi?t la ?i c?ng khong gay d?c tinh c?p cho chu?t binh th??ng. Kh? nang ?c ch? ho?t d?ng c?a enzyme ?-amylase va ?-glucosidase c?a cao n??c, methanol va butanol t? la ?i c?ng d??c kh?o sat in vitro. K?t qu? cho th?y cac cao nay d?u co kh? nang ?c ch? ho?t d?ng c?a enzyme ?-amylase va ??glucosidase co y ngh?a th?ng ke. K?t qu? trong nghien c?u nay ch?ng minh cac ch?t trong la ?i ?c ch? enzyme ?-amylase va ?-glucosidase in vitro m?t cach co y ngh?a th?ng ke va ki?m soat tinh tr?ng tang d??ng huy?t sau b?a an ? chu?t b?nh ti?u d??ng. T? cac k?t qu? d??c trinh bay ? tren cho th?y la ?i co th? d??c s? d?ng d? ki?m soat b?nh ti?u d??ng.

T? khoa: Cay ?i, ti?u d??ng type 2, h? d??ng huy?t, ?-amylase, ?-glucosidase