Neuromuscular and microvascular changes associated with chronic administration of an extract of Teucrium stocksianum in mice

This work examines the effect on the weights of vital body organs, on blood biochemical variables, on neuromuscular coordination and on cerebral microcirculation of aqueous extracts of Teucrium stocksianum, given to mice in drinking water at concentrations of 2 and 4% for 56 days. The treatment caused progressive impairment of neuromuscular coordination, as evidenced by the time spent on the rota-rod. After photochemical challenge, the time for first observable platelet aggregation in arterioles was shorter than for the control group by 22 and 45% in the 2 and 4% T. stocksianum-treated groups, respectively. Platelet aggregation on the venular side was not affected by the treatment nor were microvascular diameters. Treatment with the plant extract produced no statistically significant effect on the plasma biochemical variables that are considered indices of liver and kidney function. Histologically, brains obtained from mice treated with T. stocksianum showed loss of cerebellar Purkinje cells. Although it is likely that the accelerated platelet aggregation might have contributed to an ischaemic effect which could, at least in part, have caused the cytotoxicological changes, this does not exclude the possibility of a direct cytotoxicological effect of the plant extract. Further pharmacological and toxicological investigations on Teucrium species seem warranted.