Sedative, anxiolytic and analgesic effects of Urena sinuata L. leaf extract in animal models

The sedative and analgesic potential of Urena sinuata L. was investigated for the first time in this study. The crude methanol extract of Urena sinuata L. leaves was evaluated for its central nervous system (CNS) depressant effect using rodent behavioral models. Methanol extract of Urena sinuata at a dose of 400 mg/kg body weight, displayed a suppressive effect on motor activity, exploratory behavior (in hole cross and open field tests) and prolongation of thiopental induced sleeping time in mice. In the elevated plus-maze (EPM) test, the same dose of methanol extract significantly (p < 0.05) increased the time spent by the treated mice in EPM open arms. Analgesic potential of the extract was also evaluated for centrally acting analgesic activity using formalin induced licking response model and for peripheral analgesic action using acetic acid-induced writhing test and tail immersion tests. In formalin induced licking response model, a significant (p < 0.05) inhibition of pain compared to reference drug diclofenac sodium was observed. In acetic acid-induced writhing test and tail immersion test, the extract at 200 mg/kg body weight produced a significant reduction of writhing response and pain respectively. These results evidenced the potential sedative and analgesic effects of Urena sinuata leaves.