Hydroethanolic extract of Tropaeolum majus promotes anxiolytic effects on rats

Tropaeolum majus L., Tropaeolaceae, popularly known in Brazil as ‘capuchinha’ is widely used due its anti-inflammatory, antiseptic, anti-hypertensive and anti-depressive properties. However, scientific investigations about its effects on the central nervous system are still scarce. This study investigated the central pharmacological actions of the prolonged treatment with a hydroethanolic extract of T. majus in male Wistar rats in the elevated plus maze and hole-board behavioral models. For this, rats were daily treated with distillated water (negative control); diazepam (1 mg/kg) or hydroethanolic extract of T. majus (75, 150 and 300 mg/kg), for 29 days (by gavage) and were submitted to elevated plus maze and hole-board. Animals treated with all hydroethanolic extract of T. majus or diazepam doses increased the percentage of entries in open arms when compared to control group. However, only treatment with diazepam increased the length of time spent in the open arms of the elevated plus maze. No differences between all groups were observed regardless rearing, grooming, stretched-attend postures and defecation rates. In the HB test, in opposite to diazepam, treatment with hydroethanolic extract of T. majus did not interfere in the exploratory activity of rats. The hydroethanolic extract of T. majus promotes anxiolytic-like effects when orally administered in rats. Keywords: Alternative treatment, Anxiety, Anxiolytic, Elevated plus maze, Hole-board, Medicinal plants