Antioxidant and Acetylcholinesterase Inhibitory Activities of Selected Turkish Medicinal Plants

The use of plants for treating diseases is as old as the human species. Medicinal plants have been found to be an imporatnt supplier for novel pharmacologically active components. In the course of our investigations towards the biological activity of traditionally used medicinal plants against cancer in Kırklareli, we examined acetylcholinesterase inhibitory activities and antioxidant potential of methanol, ethyl acetate, dichloromethane and petroleum ether extracts prepared from Urtica dioica 1, Achillea millefolium ssp. pannonica 2, Malva sylvestris 3, Stachys cretica 4, Marrubium rotindifolium 5, Melissa officinalis 6, Cotinus coggryia 7, Sorbus aucuparia 8, Plantago major ssp. major 9 in vitro including the total phenols assay by Folin-Ciocalteu reagent (FCR), ferric ion reducing antioxidant power (FRAP), DPPH and superoxide free radical scavenging activities and thiobarbituric acid test using the lipid peroxidation of liposomes. Among all extracts, remarkable acetylcholinesterase inhibitory and antioxidant activity with EC₅₀ ≤ 0.5 mg/ml and highest total phenolic content (GAE > 150 mg/g extract) were found in 6, 7, 8 methanolic extracts and 6c, 7c and 8c ethyl acetate extracts. 1c, 4 and 4c extracts showed lower antioxidant activity with EC₅₀ ≤ 1 mg/ml which corresponds to the lower total phenolic contents (GAE ≤80 mg/g), whereas 1, 2, 3, 5 and 9 methanolic and 1c, 2c, 3c, 5c and 9c ethyl acetate extracts containing the least phenolics, were weakest in activity. It was concluded that the antioxidant potency is highest for ethyl acetate and methanolic extracts, followed by dichloromethan extracts, while petrol ether extracts showed no any detectable antioxidant activity.