In vitro acetylcholinesterase inhibitory activity of the essential oil from Acorus calamus and its main constituents.

The in vitro acetylcholinesterase (AChE) inhibitory potential of the hydroalcoholic extract and of the essential oil from Acorus calamus (AC) rhizomes and that of its major constituents were evaluated based on the Ellman's method. GC/MS analysis of the oil revealed that the major constituents were beta-asarone (79.54%) and alpha-asarone (8.47%). The IC50 values were obtained for the hydroalcoholic extract, the essential oil, beta-asarone and alpha-asarone and were 182.31+/-16.78 microg/mL, 10.67+/-0.81 microg/mL, 3.33+/-0.02 microM and 46.38+/-2.69 microM, respectively. Physostigmine was used as standard inhibitor with an IC50 value of 0.28+/-0.015 microM. The experimental observations revealed that the AC essential oil and its constituents have significant AChE inhibitory potential. beta-Asarone, the major phytoconstituent present in the essential oil, showed the maximum inhibitory potential.