Document Type : Research article
Department of Chemistry, Faculty of Sciences, Muğla Sıtkı Koçman University, 48000 Muğla, Turkey.
Department of Chemistry and Chemical Processing Technologies, Muğla Vocational School, Muğla Sıtkı Koçman University, 48000 Muğla, Turkey.
Department of Chemistry, University of Massachusetts, Amherst, 01003 Massachusetts, United States.
Sideritis species have been known as medicinal plants since ancient times, and used as tea in Mediterranean countries such as Turkey, Greece and Spain. They are also used for the treatment of several ailments such as a cough, common cold and gastrointestinal disorders. The aim of the present study was to perform the chemical composition, antioxidant, anticholinesterase and anti-tyrosinase activities of the essential oils of Sideritis albiflora and S. leptoclada. β-caryophyllene (21.2%) and Germacrene D (17.9%) were identified as the major compounds in S. albiflora and S. leptoclada essential oils, respectively. The essential oil of S. albiflora showed the highest lipid peroxidation inhibitory (IC50:73.8±0.8 µg/mL), DPPH free radical scavenging (28.3±0.1%), ABTS cation radical scavenging (IC50:50.6±1.0 µg/mL), reducing power (A0.05: 181.7±0.6 µg/mL), acetylcholinesterase (22.1±0.4%), butyrylcholinesterase (IC50:157.2±0.9 µg/mL) and tyrosinase (15.2±0.4%) inhibitory activities. Moreover, S. albiflora essential oil had rich total phenolic and flavonoid contents indicating 41.5±0.8 µg PEs/mg extract and 21.4±1.0 µg QEs/mg extract, respectively. This study suggests that consumption of Sideritis species as tea may protect one against melanogenesis, amnesia, and oxidative stress without any observable side effect.