Ethanol extract of Mahkota Dewa (Phaleria macrocarpa (Scheff,) Boerl.) fruit with in-vitro antidiabetic activities

Abstract

Mahkota dewa (Phaleria macrocarpa) fruit is popular in Indonesia used as an alternative or traditional medicine especially for antidiabetic. However, its mechanism and compound as antidiabetic has not been further studied yet. Therefore, the objective of this research is to elucidate its mechanism of action as insulin secretagog in clonal glucose responsive insulin secreting cells BRIN-BD11 and -glucosidase inhibitor in-vitro. The extract was further analyzed to determine its active compound. Mahkota dewa’s fruits were extracted by maceration method with ethanol 30% as solvent. The ethanol extract contains phytochemical alkaloid, flavonoid, tannin, and steroid. Insulin secretory responds after one hour incubation in 16.7 mM glucose media with concentration of 1.12, 2.25, and 4.50 mg/ml mahkota dewa fruit extract showed 1.5, 1.3, and 2.0 folds increased compared to control. However, almost the same respond compared to glibenclamide, which is an insulin secretagog drug. In-vitro assay for -glucosidase inhibitory activity was measured based on the formation of p-nitrophenol (yellow solution) through hydrolysis of substrate p-nitrophenyl -Dglucopiranoside. The concentration of the extract were 1%, 1.5%, and 2% resulted inhibition level respectively 26.40%, 29.22%, and 24.51%, which was very low compared to acarbose (99%), an - glucosidase inhibitor. The extract was further analyzed with flash chromatography, thin layer chromatography, and reconfirmed with phytochemical assay which contains flavonoid compound.