α-amylase and α-glucosidase inhibiting effects of Canna edulis Ker Gawl rhizome

Abstract

Screening inhibitors of α-amylase and α-glucosidase from medicinal plants is a topic of interestin the world. Canna edulisKer Gawl is an important rhizome plant belonging to the genus Cannaof the family Cannaceae. It is traditionally used to treat many conditions such as gonorrhea, pain, bruises, diarrhea, hepatitis, chest pain and heart diseases.The potential of this plant in the treatment and prevention of diabetes has rarely been documented.This study reports,for the first time,α-amylase and α-glucosidase inhibiting effectsand the phytochemical profileof therhizome part of C.edulis.C. edulisrhizome was extracted with 96% ethanol,and then successively fractionated with n-hexane, ethyl acetate and water.α-amylase and α-glucosidase inhibiting assays were performed to investigate the enzyme inhibitory activities of the total extract and fractions. Qualitative phytoconstituents were analyzed using chemical reactions. The results showed that all extract and fractions had α-amylase and α-glucosidase inhibiting effects in a dose dependent manner. The ethyl acetate fraction exhibited the strongest inhibiting activities against both enzymes (IC₅₀, 45.24 ±2.90 and 90.09 ±6.70 μg/mL for α-amylase and α-glucosidase inhibiting assays, respectively) and its effects were significantly higher than the positive control (p < 0.05). The water fraction showed the lowest effects.C. edulisrhizome contained abundant secondary metabolites including cardiac glycosides, cholesterols, glycosides, flavonoids, sterol and triterpenes, tannins, steroids, saponins, coumarins and proteins. All these secondary metabolites, except for saponin, were found in the ethyl acetate fraction.C.edulisrhizome couldserve asa potential candidatetofind novelanti-α-amylase and anti-α-glucosidaseagentsand to develop supplementary products for controlling hyperglycemia.