Screening of acetylcholinesterase inhibitory activity in essential oil from Myrtaceae

Abstract

Objective: This research was to investigate acetylcholinesterase inhibitory (AChEI) activity of the essential oil from Myrtaceae and its components. Materials and Methods: The essential oils were extracted from a fresh leave of Myrtaceae plants: Eucalyptus globulus Labill (Eucalyptus), Melaleuca cajuputi Powell (Samed-Khao), Melaleuca citrina (Curtis) Dum. Cours (Bottlebrush tree), Psidium guajava Linn. (Gauva), Syzygium cumini (L.) Skeel (Wha), and Syzygium samarangense (Blume) Merr. and L. M. Perry (Chompoo Nam Dok Mai) by hydrodistillation and analyzed chemical constituent by gas chromatography. The AChE inhibition was determined based on Ellman’s method. Results: The essential oil from M. citrina presented the greatest inhibitory activity (71.77 ± 2.11%) and followed by E. globulus (47.65 ± 2.26%), P. guajava (24.96 ± 2.38%), M. cajuputi (21.18 ± 0.54%), S. cumini (19.97 ± 1.10%), and S. samarangense (13.78 ± 1.52%), respectively. Alpha-pinene was found in the essential oil of 6 species. 1,8-Cineole was the main compound of the essential oil from M. citrina and acts as an active constituent on AChEI. The essential oil from M. cajuputi, S. cumini, and S. samarangense contained a small amount of α-pinene, and without 1,8-cineole, then they were less potency on AChEI. Conclusion: The essential oil containing higher amount of 1,8-cineole presented strong activity to inhibit the AChE. Moreover, there are also other constituents in the essential oils that may affect the AChEI activity and also present synergistic effect for AChEI. © 2019, Faculty of Pharmaceutical Sciences, Chulalongkorn University. All rights reserved.