Chemical characterization, mineral content and radical scavenging activity of Sideritis scardica and S. raeseri from R. Macedonia and R. Albania

Abstract

Chemical characterization was made of over-ground flowering parts of Sideritis scardica from R. Macedonia and S. raeseri from both R. Macedonia and R. Albania. GC/FID/MS investigation of the n-hexane extracts revealed more than 90 components, dominated by diterpenes and hydrocarbons. The most abundant components were hentriacontane, nonacosane and heptacosane, and two other components both with MW=286, probably diterpenes, which were not fully identified. In addition, the content of total phenols, made by the Folin-Cioclateu method, ranged up to 50.8 and up to 48.9 mg gallic acid/g for S. scardica and S. raeseri, respectively. Free radical scavenging activity was evaluated by DPPH assay and the activity, presented as IC50 values, ranged from 3.2-8.9 mg/mL and 7.6-12.6 mg/mL for S. scardica and S. raeseri, respectively. The content of twenty minerals in dried over-ground parts of the plants and in water tea-infusions were determined by the ICP-AES method and some of them alternatively by ETAAS. The most abundant minerals were K > Ca > Mg > P > Fe > Al > Na. The microelements and toxic elements contents were represented in the following order: Zn > Mn > B > Ba > Cu > Sr > Ni > Cr > Co, and Cd > Pb > As, respectively. Water tea-infusions contained a large portion of the total K, P, Na, Cu and Pb, but smaller amounts of the other elements.