Effect of Gallic Acid on Reactivation of Acetylcholinesterase and Butyrylcholinesterase Inhibited by Diazinon in Vitro and in Vivo

Diazinon is an organophosphate insecticide that binds to the acetylcholinesterase enzyme after metabolization causing its inactivation. Galic acid is a polyphenolic compound with nucleophilic properties. The aim of this study was to investigate the effects of gallic acid on reactivation of acetylcholine and butyrylcholinesterase inhibited by diazinon in mice and human serum and erythrocytes.

The animals were divided into seven groups, including a control group that received corn oil as a solvent and other groups that received diazinon (80 mg/kg), atropine (20 mg/kg), and pralidoxime (20 mg/kg). Gallic acid was injected intraperitoneally at 50, 100, and 200 mg/kg. Cholinesterase levels (acetylcholine and butyrylcholinesterase) were evaluated after 3 and 24 h of intoxication in mice serum and erythrocytes. In addition, in vitro studies were done in human serum and RBCs.

Activities of cholinesterase in serum and erythrocytes significantly decreased after 3 and 24 hours of poisoning in diazinon-treated group compared to control group in vivo and in vitro. Co-treatment with atropine and gallic acid (at all doses) significantly increased cholinesterase activity compared to the diazinon group in vitro and in vivo (P< 0.0001).

Combination therapy with gallic acid (at different doses) and atropine reduced inhibition of cholinesterase activity caused by diazinon and improved its reactivation. Gallic acid reactivates cholinesterase activity which might be due to hydroxyl groups in its compounds.