ANTIOXIDANT ACTIVITY, PHENOLIC AND MINERAL CONTENT OF Stachys germanica L. (LAMIACEAE)

Mineral composition, total phenol and flavonoid contents, HPLC profile and antioxidant activity of Stachys germanica (Lamiaceae) from the mountain range Svrljiske planine (south-east Serbia) were determined for the first time. The metal content analysis of different parts of S. germanica (leaves, blossom, seed and stem) was performed using ICP-OES and mean values for K, Na, Ca, Mg, Cu, Fe, Zn, Ni, Cr, Ba, Mn and B were obtained. Among the principal elements, potassium was found in the highest content followed by sodium, calcium and magnesium. Iron was the most abundant among trace elements, followed by zinc, barium and copper. Total phenolic and flavonoid contents of S. germanica methanol extracts were ranged from 43.0 (blossom) to 75.0 (leaves) mg gallic acid equivalents per g of dry weight and between 33.0 (blossom) to 54.0 (leaves) mg catechin equivalents per g of dry weight, respectively. HPLC-DAD analysis of the extracts was performed and phenolic acids (ferulic, p-coumaric and caffeic acid) and flavonoids (catechin, hesperetin and rutin) were identified and quantified. S. germanica methanol extracts were found to have significant antioxidant activities, as evaluated by 4 different in vitro methods (scavenging 1,1-diphenyl-2-picrylhydrazyl and 2,2'azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) radicals, iron(III) to iron(II) reduction assay and ferric-reducing antioxidant power assay).