Neuropharmacological evaluation of Hibiscus rosa sinensis roots in experimental animals

Objective: To investigate the effect of the methanolic extract of Hibiscus rosa sinensis roots (H. sinensis) on the central nervous system in mice and rats. Materials and methods: The methanolic extract of H. sinensis was studied on pentobarbital-induced sleeping time, elevated plus maze, hole board test, foot shock-induced aggression, haloperidol-induced catalepsy, lithium-induced head twitches, locomotor activity, acetic acid-induced writhing and hot plate analgesiometer at various doses (50 200 mg/kg), intraperitoneally for sedative, anxiolytic, antipsychotic, muscle relaxant and analgesic activities. Results: The extract prolonged pentobarbital-induced sleeping time indicating sedative effect. The extract increased the time spent in open arms and the number of head dips in elevated plus maze and hole board test respectively demonstrating anxiolytic activity. H. sinensis decreased number of fights in foot shock-induced aggression and potentiated haloperidol-induced catalepsy in dose dependent manner showing antipsychotic effect. The extract significantly inhibited head twitches induced by lithium suggesting its inhibitory effect on serotonergic system. The H. sinensis significantly decreased the locomotor activity in dose dependent manner. The extract showed potential analgesic activity in acetic acid-induced writhing and hot plate analgesiometer. The H. sinensis attenuated the behavior mediated by the dopaminergic and serotonergic system and potentiated the GABAergic actions. Conclusion: The results suggest that the methanolic extract of Hibiscus rosa sinensis has potential neuropharmacological activities.