Study of Chemical Composition, Anticholinesterase and Antioxidant Properties of Essential Oil and Ethanolic Extract from Thymus Numidicus Poiret, an Algerian Endemic Medicinal Plant

This study is aimed to evaluating the anticholinesterase and antioxidant properties of essential oil (EO) and ethanolic extract (EE) from Thymus numidicus Poiret leaves, an Algerian endemic aromatic and medicinal plant from Mila region. The analysis of the EO by GC and GC-MS revealed the presence of thymol (42.1%), carvacrol (22.1%), and linalool (8.5%) as major compounds. 3-Isoferulic acid, trans, di-methoxycinnamic acid, rosmarinic acid, and rutin were identified as the most abundant compounds in EE analyzed by HPLC-DAD-UV. The EO exhibited a significant inhibition activity against both butyrylcholinesterase (BChE) and acetylcholinesterase (AChE) with IC50 of 158.94 and 189.41 µg/mL respectively, whereas the EE failed to reach 50% inhibition. The antioxidant activity was evaluated by the β-carotene bleaching assay, the iron- and copper-reducing powers, and the inhibition of the DPPH• and ABTS•+ radicals. The EO exhibited potent antioxidant activity in the ABTS•+, iron- and copper-reducing power tests for EO (IC50: 3.61, 7.99, 8.01 μg/mL respectively) compared with the butylhydroxyroluene (BHT; IC50: 12.99, 43.48, and 9.62 μg/mL respectively). However, this oil showed low activity in the DPPH? test (IC50 = 591.72 versus 22.32 μg/mL for BHT). Generally, the EE showed good activity with all the antioxidant tests. Thus, T. numidicus might be a valuable material for possible nutraceutical and pharmaceutical applications.