Antioxidant properties and phenolic variation in wild populations of Marrubium vulgare L. (Lamiaceae)

The phenolic profile of six wild growing Marrubium vulgare L. (Lamiaceae) collected from different bioclimatic zones was investigated. Ethanol, ethyl acetate and residual water fractions were investigated for their antioxidant activity using DPPH assay. Ethyle acetate (EtOAc) fraction showed the highest antioxidant capacity with IC50 values ranging from 68.98 to 118.15 mu g/mL. Eight phenolic acids and five flavonoids were detected in the ethyle acetate fraction and quantified by high performance liquid chromatography (HPLC) coupled to a diode array detector (DAD), among them the concentration of quercetin-3-D-O-galactoside (5.84-14.46 mg/g DW) was the highest. Metabolic profile, consisting of glycosylated flavonoids and phenolic acids, was very regular with only quantitative differences and absences limited to minor components. A remarkably significant quantitative variation for the major components was noted. On the basis of chemical composition, principal component analysis and cluster analysis, M. vulgare was classified into two groups. Population grouping was not concordant with bioclimatic appurtenance. These results indicate that M. vulgare can be used in dietary applications with a potential to reduce oxidative stress. The pronounced chemical diversity between populations is discussed to possibly be linked to the variation of soil properties and microclimate conditions. (C) 2015 Elsevier B.V. All rights reserved.