Linaria Mill. genus plants contain compounds such as alkaloids, phenolic compounds, and terpenoids and have antitumor, antiacetylcholinesterase, anti-inflammatory, analgesic, antioxidant, antibacterial, antidiabetic, antifungal, and diuretic activities (1, 2). In the present study, endemic Linaria corifolia Desf. plant aerial parts were extracted 20% aqueous methanol. This extract was extracted with petroleum ether, the aqueous phase remaining from the petroleum ether partition was extracted successively with chloroform, ethylacetate and n-butanol. As a result of the separation of n-butanol extract by several column chromatography, 4 different iridoid glycosides were obtained as antirrhinoside, 6-β-hydroxyantirrhide, catalpol and aucubin. The structures of the isolated pure compounds were elucidated using spectral methods (1H and 13C NMR, COSY, HSQC and HMBC spectrum) and by comparison with literature data.

L. corifolia extracts and pure iridoid glycosides that were isolated from n-butanol extract were examined the in vitro acetylcholinesterase inhibition activity triplicate based on the Ellman’s method (3, 4). When compared to other extracts, an increase in the % inhibition values depending on the concentration was observed for the n-butanol extract. Among the pure compounds isolated from the n-butanol extract, the activity of catalpol was higher than the other compounds, and a significant increase in % inhibition values was found according to the concentration. The % inhibition values of n-butanol extract at 50, 100, 200 and 400 μg/ml concentrations, respectively; 2.71±0.72, 11.06 ±1.48, 11.22±1.13, 17.19±1.39. It was calculated as 6.65±3.86, 13.33 ±3.25, 18.93±8.58 at 20, 25 and 100 μg/ml concentrations of the catalpol compound. Compared to physostigmine salicylate used as a standard compound (44.47±0.37%, 62.27±2.16, 70.82 ±3.91, 77.80±0.91 at concentrations of 1, 2, 2.5 and 5 μg/ml; IC50: 1.25±0.14 μg/ml) the activities of the n-butanol extract and catalpol were lower.