Comparative analysis of phenolic compositions and biological activities of three endemic Teucrium L. (Lamiaceae) species from Turkey

This study investigates the chemical compositions and biological activities of the methanol extracts of three endemic Teucrium species (T. ekimii ,T. pestalozzae and T. semrae) collected from Turkey. Total phenolic and flavonoid contents were assessed spectrophotometrically. The total phenolic and flavonoid content in the T. ekimii methanolic extract were importantly higher than other both extracts. The polyphenolic components of the extracts were identified by liquid chromatography. Seven phenolic compounds were identified namely catechin, rutin, luteolin, apigenin chlorogenic acid, sinapic acid and rosmarinic acid. Antioxidant activities were determined by five in vitro assays namely phosphomolybdenum assay, 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity, beta-carotene bleaching assay, ferric ions reducing antioxidant power (FRAP) and cupric ions reducing antioxidant capacity (CUPRAC). The total antioxidant activity method exhibited that T. ekimii methanol extract exerted better antioxidant activity. The methanol extract of T. ekimii showed better antiradical scavenging activity as measured by DPPH assay. The antimicrobial capacities were determined by agar diffusion assay. Three endemic Teucrium species tested showed slight antibacterial activity only against Aeromonas hydrophila, Klebsiella pneumoniae and Streptococcus pneumoniae. The findings showed that three endemic Teucrium species may be utilized as natural sources of antioxidant and antimicrobial compounds in food and farmacy products.