Effects of CATECHIN on reserpine-induced vacuous chewing movements: behavioral and biochemical analysis

This study evaluated the effect of (+)-catechin, a polyphenolic compound, on orofacial dyskinesia (OD) induced by reserpine in mice. The potential modulation of monoaminoxidase (MAO) activity, tyrosine hydroxylase (TH) and glutamic acid decarboxylase (GAD₆₇) immunoreactivity by catechin were used as biochemical endpoints. The interaction of catechin with MAO-A and MAO-B was determined in vitro and in silico. The effects of catechin on OD induced by reserpine (1 mg/kg for 4 days, subcutaneously) in male Swiss mice were examined. After, catechin (10, 50 or 100 mg/kg, intraperitoneally) or its vehicle were given for another 20 days. On the 6th, 8th, 15th and 26th day, vacuous chewing movements (VCMs) and locomotor activity were quantified. Biochemical markers (MAO activity, TH and GAD₆₇ immunoreactivity) were evaluated in brain structures. In vitro, catechin inhibited both MAO isoforms at concentrations of 0.34 and 1.03 mM being completely reversible for MAO-A and partially reversible for MAO-B. Molecular docking indicated that the catechin bound in the active site of MAO-A, while in the MAO-B it interacted with the surface of the enzyme in an allosteric site. In vivo, reserpine increased the VCMs and decreased the locomotor activity. Catechin (10 mg/kg), decreased the number of VCMs in the 8th day in mice pre-treated with reserpine without altering other behavioral response. Ex vivo, the MAO activity and TH and GAD₆₇ immunoreactivity were not altered by the treatments. Catechin demonstrated a modest and transitory protective effect in a model of OD in mice.