Anxiolytic, sedative, and hypnotic activities of aqueous extract of Morinda citrifolia fruit

Abstract

Morinda citrifolia (Indian mulberry or noni) fruit has been long used as a folk medicine for a wide range of health purposes as it is claimed to have analgesic, antiinflammatory, antioxidant, detoxifier, and cell-rejuvenator properties. A recent study has revealed central nervous system suppressant nature of its extract. Hence, the present study has evaluated the anxiolytic, sedative, and hypnotic effects of the aqueous extracts of Morinda citrifolia in rodents in comparison to diazepam. Anxiety was assessed by ‘Isolation-induced aggression’ model, sedation by ‘Spontaneous locomotor activity using actophotometer’ and hypnotic activity by ‘Prolongation of ketamine-induced sleeping time’. Six male mice were used for each of the groups and postdose, all the six that received diazepam had shown an inhibition of aggression, whereas in the test group, five of six mice and none in the control group had shown an inhibition of aggression (P = 0.0007). Similarly, for the sedative activity, the total number of spontaneous locomotor activity at 30 min following drug administration was found to be 364.67 ± 10.74, 123.16 ± 8.33, and 196.67 ± 3.7, while at 60 min it was found to be 209 ± 12.98, 49 ± 5.78, and 92 ± 2.5 (mean ± SD) for the control, standard, and test groups of mice respectively (P < 0.001). Hypnotic activity was measured by prolongation of ketamine-induced sleeping time wherein the onset and duration of loss of righting reflex were compared among each group of mice. The time in minutes for the onset in control, standard, and test groups was 4.01 ± 0.22, 1.23 ± 0.05, and 2.23 ± 0.07, respectively. The duration of loss of righting reflex was 44.23 ± 0.59, 56.03 ± 1.34, and 50.57 ± 0.36, respectively. Both these were statistically significant (P < 0.001). However, more clinical studies are needed to assess the long-term effects of the extract in humans.