Isolation and identification of α-glucosidase inhibitory compounds from ethyl acetateextract of Sirih hijau (Piper betle L.)

Abstract

It has been ascertained that the extract of sirih hijau (Piper betle Linn) possesses some bioactivities, particularly its ability to inhibit the α-glucosidase enzyme. However, certain compounds contained in the betel leaf extract which can act as glucosidase enzyme inhibitors are not widely known. In this research, betel leaves were air-dried and mashed into dry powder. The dry powder was macerated in methanol and filtered, and the isolate results were partitioned successively with n-hexane and ethyl acetate. The isolation of the compound was done by column chromatography using silica gel 60 mesh as the stationary phase and a mixture of chloroform-methanol (9:1, v/v; and 8:2, v/v). Four fractions were obtained with various combinations of solvents, one of which was a mixture of benzene-ethyl acetate (7:3, v/v) which resulted in a pure isolate. The structure of the isolated molecule was determined by using the spectroscopy procedure based on ultraviolet-visible, infra-red, and nuclear magnetic resonances spectroscopy. It gave rise to α-glucosidase inhibitory potential evaluated in vitro based on UV-Vis spectrometry. An isolated compound, identified as 2-hydroxychavicol, was successfully isolated from Piper betel leaves. The compound has an α-glucosidase inhibitory potential with IC50 value of 72,87 ppm.