Xiong_1995_Zhongguo.Yao.Li.Xue.Bao_16_21

AIM To study the effects of isovanihuperzine A (IVHA) on cholinesterase and scopolamine-induced memory deficit. METHODS: AChE and BCHE activities were determined by the colorimetric method of Ellman. The Ki value was determined by the plotting method of Lineweaver and Burk. In a behavioral test, rats were trained to perform a radial arm maze task using a partially baited procedure. RESULTS: The anti-AChE activity of IVHA was comparable to huperzine A (Hup-A), and was more potent than those of physostigmine and galanthamine with an IC50 value of 0.11 mumol.L-1. IVHA was a mixed competitive type with a Ki value of 32 nmol.L-1. It bound to AChE in a reversible manner. IVHA at a dose of 0.2 mg.kg-1 ip significantly reversed scopolamine-induced working memory and reference memory impairments in radial arm maze. CONCLUSION: IVHA is a new potential reversible AChE inhibitor and merits further study as a cognitive enhancer.