Antioxidant potential and phenolic composition of extracts from Stachys tmolea: An endemic plant from Turkey

This study aims to screen bioactive compounds from Stachys tmolea an endemic plant from Turkey. The phenolic composition of the aerial parts of S. tmolea was investigated using methanol and water as solvents. Furthermore, the total antioxidant, radical scavenging, reducing power, and metal chelating activities of S. tmolea extracts were determined. Results show that S. tmolea is endowed with phenolic compounds with considerable antioxidant properties. Twenty compounds were identified and quantified in different extracts. Methanol was shown to be the most effective for the extraction of phytochemicals. The major compounds identified in the methanolic extract S. tmolea were verbascoside (3169.81 +/- 14.38 mu g/g dry plant), chlorogenic acid (1120.14 +/- 41.24 mu g/g dry plant), and apigenin 7-glucoside (146.46 +/- 9.88 mu g/g dry plant). Nevertheless, the antioxidant activities tested with different methods revealed no significant differences between aqueous and methanolic extracts. The current finding confirmed the importance of S. tmolea and Stachys genus in general which is used traditionally as mountain tea in Turkey and Iraq. Thus, further investigations should be done for the isolation and purification of bioactive molecules for both medicinal and industrial uses.