Phytochemical Content, In Vitro Antioxidant, and Cholinesterase Inhibitory Activities Determination of Endemic Linaria corifolia Desf

Objective: In our study, we researched the chemical composition of Linaria corifolia Desf. We also tested in vitro antioxidant, and anticholinesterase activities of different extracts, and compounds from L. corifolia. Methods: We isolated from ethyl acetate and n-butanol extracts of L. corifolia aerial parts. We used various spectroscopic methods. We also compared the results with data in the literature. This allowed us to determine the structure of the compounds. We used different spectroscopic methods and comparisons with literature data to determine the structure of the compounds. We evaluated the antioxidant activities of 20% aqueous methanol, ethyl acetate, and n-butanol extracts using DPPH, ABTS Radical Scavenging Effect, and CUPRAC Assay, and also examined total phenol and flavonoid contents. We used Ellman's method to find the cholinesterase inhibitor activities of the extracts, and isolated compounds. Results: We isolated 6 compounds in ethyl acetate and n-butanol extracts. These compounds have terpenoid (iridoid glycosides), and phenolics (flavonoid, and phenylpropanoid structures). We isolated linariin and acteoside (verbascoside) from ethyl acetate. We isolated antirrhinoside, 6-ß-Hydroxyantirrhide, catalpol, and aucubin from n-butanol extract. The ethyl acetate extract was most active in all antioxidant methods due to its high phenolic content. In contrast to phenolic content, n-butanol extract had more flavonoids. The ethyl acetate extract had higher acetylcholinesterase inhibitory activity at 200 and 400 μg/ml. Linariin had the highest acetylcholinesterase inhibitory effect among the pure compounds. The extracts and pure compounds inhibited butyrylcholinesterase less than acetylcholinesterase. Conclusion: The isolated compounds are new compounds for the L. corifolia plant. The plant's cholinesterase inhibitor activity was investigated for the first time. We found low anti-acetylcholinesterase and butyrylcholinesterase activities.