Paper Report for: Lopez_2015_Chem.Biol.Interact_229_36
Reference
Title: Acetylcholinesterase activity of electric eel is increased or decreased by selected monoterpenoids and phenylpropanoids in a concentration-dependent manner Lopez MD, Campoy FJ, Pascual-Villalobos MJ, Munoz-Delgado E, Vidal CJ Ref: Chemico-Biological Interactions, 229:36, 2015 : PubMed
The profitable insecticidal action of monoterpenoids prompted us to test their efficiency against stored-grain beetle species, via inhibition of acetylcholinesterase (AChE). For this, we first studied the ability of the monoterpenoids geraniol, linalool, camphor, fenchone, carvone and gamma-terpinene, besides the phenylpropanoids trans-anethole and estragole to inhibit Electrophorus AChE. The results indicated that while AChE activity increased (15-35%) with 40muM geraniol, camphor, gamma-terpinene and linalool, the activity decreased (60-40%) with 5mM carvone, gamma-terpinene, and fenchone. The Km for AChE was 0.52+/-0.02mM in control assays, which fell to 0.28+/-0.01mM or 0.32+/-0.01mM in assays with 20muM linalool or gamma-terpinene added. In the millimolar range, the terpenoids behaved as weak inhibitors. Unexpectedly, AChE inhibition by camphor, carvone, gamma-terpinene, and fenchone gave Hill numbers ranging 2.04-1.57, supporting the idea that AChE was able to lodge more than one monoterpenoid molecule. The plots of 1/v vs. 1/S at varying monoterpenoid provided straight lines, fenchone and gamma-terpinene acting as competitive inhibitors and carvone and camphor as non-competitive inhibitors. Moreover, the secondary plots of the slope KM(app)/Vmax(app) vs. [I] and of 1/Vmax(app) vs. [I] gave parabolic curves, which lent support to the proposed capacity of AChE to bind more than one monoterpenoid molecule. The fitting of the curves to a second-order polynomial equation allowed us to calculate the inhibition constants for the interaction of AChE with fenchone, gamma-terpinene, carvone and camphor. The previously unnoticed increase in AChE activity with monoterpenoids should be considered as a reminder when advising the use of essential oils of plants or their constituents as anti-AChE agents to attenuate pathological signs of Alzheimer's disease.
        
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Lopez MD, Campoy FJ, Pascual-Villalobos MJ, Munoz-Delgado E, Vidal CJ (2015) Acetylcholinesterase activity of electric eel is increased or decreased by selected monoterpenoids and phenylpropanoids in a concentration-dependent manner Chemico-Biological Interactions229: 36-43
Lopez MD, Campoy FJ, Pascual-Villalobos MJ, Munoz-Delgado E, Vidal CJ (2015) Chemico-Biological Interactions229: 36-43