In vitro Antioxidant and Anticholinesterase Activities of Senecio massaicus Essential Oil and Its Molecular Docking Studies as a Potential Inhibitor of Covid-19 and Alzheimer’s Diseases

Abstract The composition of the essential oil obtained from the dried aerial parts of Senecio massaicus was analyzed by GC/MS. Twenty-two components have been identified and represented 97.41 % of the total oil composition. The major constituents of the essential oil were m-cymene (30.58 %), n-hexadecanoic acid (14.88 %) and docosane-11-decyl (10.43 %). Four methods were used to determine the antioxidant activity: DPPH, ABTS, CUPRAC and reducing power assay. The results indicate that the essential oil extract has moderate to low activity compared to the reference antioxidant compounds. In vitro anticholinesterase activity of the essential oil has also been studied. It exhibited higher inhibitory activity against butyrylcholinesterase (BChE) than against acetylcholinesterase (AChE). Docking studies conducted for Alzheimer's disease-related enzymes have displayed that compounds docosane-11-decyl and octaethyleneglycol monododecyl ether have strong potency, and compounds 15,15’Bi1,4,7,10,13-pentaoxacyclohexadecane and n-Hexadecanoic acid have moderate inhibitory potential. In addition, these three compounds (Docosane-11-decyl, octaethyleneglycol monododecyl ether and 15,15’Bi1,4,7,10,13-pentaoxacyclohexadecane) of the essential oil displayed strong interaction against SARS-CoV-2 main protease and Nsp15 endoribonuclease. Therefore, it could be useful to provide anticholinesterase agent and anti-coronavirus candidate drugs.