A comparative MS-based metabolomics study and in-vitro antidiabetic assay of galangals, turmeric and ginger aided by molecular networking and chemometrics

Abstract

Ginger and turmeric and the less explored galangals, are economically important spices belonging to the Zingiberaceae family, widely used in traditional medicines and nutraceuticals. The present study provides the first comparative MS based metabolomics investigation of galangals compared to major ginger drugs and in relation to their in vitro antidiabetic effects. UPLC-MS/MS metabolomic profiles of galangals, turmeric, and ginger were analyzed using GNPS molecular networking leading to the annotation of 85 metabolites of which several are first time to be reported in galangals. Principle component analysis (PCA) and orthogonal projection to latent structures discriminant analysis (OPLS-DA) of UPLC-MS/MS profiles revealed the enrichment of flavonoids, styrenes and oxylipids in the extracts of both galangals, whereas gingerols, aryl- and diarylheptanoids were characteristic to ginger and turmeric, respectively. Aroma profiling using SPME–GC–MS identified 96 volatiles belonging to sesqui- and monoterpene derivatives. Multivariate data analysis of GC-MS dataset revealed calamenene, guaia-1(10),11-diene and selina-3,7(11)-diene as characteristic to ginger and turmeric aroma profiles. In contrast, greater galangal was enriched in acetoxychavicol acetate, aristolene, α-farnesene versus abundance of γ-elemene in lesser galangal. Additionally, methanolic extracts of both galangals exerted potential in vitro α-glucosidase inhibitory effect accentuating its potential antidiabetic activities.