Research Information System
Revista de Chimie, vol.63, no.5, pp.465-469, 2012 (SCI-Expanded)
Sideritis species have very high antioxidant activity and and are used in a range of treatments by alternative medicine. This study examined the antioxidant activities and phenolic compositions of endemic 2 Sideritis species (Sideritis phrygia Bornm and ideritis bilgerana P.H. Davis), which were collected in the Konya region of Turkey. The oil content was extracted with petroleum ether using a soxhlet extractor. The defatted plant materials were extracted with methanol and then filtered and concentrated in vacuo at 45 °C. Finally, the extracts were lyophilized and stored in the dark at +4°C until analyzed for antioxidant activity. Total phenol concentration of the extracts were estimated with Folin-Ciocalteu reagent using gallic acid as standard, free radical scavenging activities were determined based on DPPH(2,2-diphenyl-l-picrylhydrazyl) and ferric reducing antioxidant power (FRAP) was determined based on the method proposed by Oyaizu. Results were compared with standard BHT(Butylated hydroxytoluene) and BHA (Butylated hydroxyanisole). The phenolic composition of the samples was determined using HPLC. The results indicated that S. phrygia and S. bilgerana showed significant antioxidant effect and 6 phenolic compounds used in standard phenolic compounds. S. phrygia showed higher antioxidant capacity than S. bilgerana.