Prospective neuro-muscular protection of Theaflavin gallate and tea extract by suppressing acetylcholinesterase in rat, verified by in vitro and MD simulation studies

Abstract

Possible therapeutic interventions of acetylcholinesterase induction were studied. Inhibition of AChE might be helpful in treating the neuro-muscular diseases. Over-expressions of acetylcholinesterase (AChE), a key regulation of the neurotransmitter acetylcholine influences some neurodegenerative/neuro-muscular disorders. Present study evaluated the effect of black-tea components on AChE-activity in in vitro, and in vivo i.e. arsenic-intoxicated (0.6ppm/day/4-weeks) rat  brain-AChE inhibition. Inhibitory-effects and enzyme kinetics on purified-AChE were screened from ten pure teaphytochemicals. In vivo experiment and bioinformatics studies were also performed. Pure theaflavin-digallate and theaflavin-monogallate showed promising AChE inhibitory effects/kinetics in dose-dependent/mixed-type manner with IC50 values, 1.6 μM and 3.3 μM, respectively. Tea galloyl-ester catechins compounds inhibited AChE with IC50 values of 41-67 μM. Arsenic exposure increased AChE activity in rat cerebellum which was significantly restored by black-tea paralleling with our in vitro results. Molecular-docking and MD-simulation (GROMACS2021.2 server) of AChE (PDB Id:4M0E) and the experimental compounds suggests that theaflavin-digallate showed the lowest Atomic-Contact-Energy -369.87 kcal/mol and hampers the enzyme catalytic-hydrolytic-action and nucleophilic attack by SER203 supporting the in vitro and animal experimental results. Compared to other flavonoid or positive-control inhibitor eserine sulfate, TFDG and TFMG demonstrated significant inhibition of AChE. In conclusion, current MD-simulation, in vitro, and in vivo data may help treat certain cholinergic diseases. Further studies are suggested.