Metabolomic analysis of Sclerocarya birrea (A. Rich) Hochst : to determine the differences in chemical profile and anti-diabetic properties in relation to geographical distribution

Abstract

Metabolomics is a discipline where metabolites are assessed, identified and quantified in different samples. Metabolites are crucial components of the biological system and highly informative about its functional state due to the closeness to functional endpoints and to the organism’s phenotypes. 1H NMR and LC-MS, the commonly used metabolomics analytical platforms were used to annotate the metabolites found in Sclerocarya birrea (S. birrea) leaves from five South African provinces, Limpopo (L), Gauteng (G), North West (NW), Mpumalanga (M) and KwaZulu-Natal (KZN). Supervised Orthogonal Partial Least Square – Discriminant Analysis (OPLS-DA) of the full spectra revealed a clear differentiation of S. birrea leaves from five provinces. In addition, the level of common metabolites were measured and compounds previously found to have anti-diabetes potential ((-)-epicatechin 3-0-galloyl ester, myricetin-3-0-α-L-rhamnopyranoside, gallic acid and Kaempferol-3-0-α-L-rhamnopyranoside) were annotated in the samples. The samples from the five provinces showed anti- diabetic activity when exposed to an in-vitro glucose uptake assay, with the highest activity observed in male samples from M. The sample presented high concentrations of (-)-epicathechin 3-0-galloyl ester, one of the metabolites with anti-diabetes activity. Overall 1H NMR and LC-MS metabolic profiling were successfully applied to discriminate all five sources of S. birrea leaves, and obtained qualitative information of many common metabolites