GC-MS analysis and in vitro antioxidant and enzyme inhibitory activities of essential oil from aerial parts of endemic Thymus spathulifolius Hausskn. et Velen

We investigated the antioxidant and enzyme inhibitory activities and chemical composition of the hydro-distilled essential oil (0.35% yield) from aerial parts of Thymus spathulifolius. Antioxidant capacity of the oil was assessed by different methods including free radical scavenging (DPPH and ABTS), reducing power (FRAP and CUPRAC) and phosphomolybdenum assay. Inhibitory activities were analyzed against acetylcholinesterase (AChE), butyrylcholinesterase (BChE), alpha-amylase, alpha-glucosidase, and tyrosinase. Twenty-one constituents were identified representing 97.2% of the total oil with thymol (50.5%), borneol (16.7%) and carvacrol (7.7%) as the major components. The essential oil exhibited good antioxidant activity with IC50 values of 3.82 and 0.22 mg/mL determined by free radical scavenging DPPH and ABTS, respectively. EC50 values of FRAP and CUPRAC were found to be 0.12 and 0.34 mg/mL, respectively. The results of the present study support the uses of T. spathulifolius essential oil as a source of natural antioxidants and bioactivities for functional foods and phytomedicines