Linarin Inhibits the Acetylcholinesterase Activity In-vitro and Ex-vivo

Linarin is a flavone glycoside in the plants Flos chrysanthemi indici, Buddleja officinalis, Cirsium setosum, Mentha arvensis and Buddleja davidii, and has been reported to possess analgesic, antipyretic, anti-inflammatory and neuroprotective activities. In this paper, linarin was investigated for its AChE inhibitory potential both in-vitro and ex-vivo. Ellman's colorimetric method was used for the determination of AChE inhibitory activity in mouse brain. In-vitro assays revealed that linarin inhibited AChE activity with an IC50 of 3.801 ± 1.149 μM. Ex-vivo study showed that the AChE activity was significantly reduced in both the cortex and hippocampus of mice treated intraperitoneally with various doses of linarin (35, 70 and 140 mg/Kg). The inhibition effects produced by high dose of linarin were the same as that obtained after huperzine A treatment (0.5 mg/Kg). Molecular docking study revealed that both 4'-methoxyl group and 7-O-sugar moiety of linarin played important roles in ligand-receptor binding and thus they are mainly responsible for AChE inhibitory activity. In view of its potent AChE inhibitory activity, linarin may be a promising therapeutic agent for the treatment of some diseases associated with AChE, such as glaucoma, myasthenia gravis, gastric motility and Alzheimer's disease.