GC-MS-Based Metabolite Profiling of Cosmos caudatus Leaves Possessing Alpha-Glucosidase Inhibitory Activity

Cosmos caudatus, which is known as Ulam Raja, is an herbal plant used in Malaysia to enhance vitality. This study focused on the evaluation of the -glucosidase inhibitory activity of different ethanolic extracts of C. caudatus. Six series of samples extracted with water, 20%, 40%, 60%, 80%, and 100% ethanol (EtOH) were employed. Gas chromatography-mass spectrometry (GC-MS) and orthogonal partial least-squares (OPLS) analysis was used to correlate bioactivity of different extracts to different metabolite profiles of C. caudatus. The obtained OPLS scores indicated a distinct and remarkable separation into 6 clusters, which were indicative of the 6 different ethanol concentrations. GC-MS can be integrated with multivariate data analysis to identify compounds that inhibit -glucosidase activity. In addition, catechin, -linolenic acid, -D-glucopyranoside, and vitamin E compounds were identified and indicate the potential -glucosidase inhibitory activity of this herb. Practical Application GC-MS and multivariate data analysis was applied to discriminate Cosmos caudatus samples extracted with water and different ratio of ethanol. Orthogonal partial least-squares (OPLS) model developed was used to determine the major metabolites contributed to -glucosidase inhibitory activity. This approach also has the ability to predict the bioactivity of a new set of extracts based on a developed validated regression model that is important for quality control of the herb preparation.