Evaluation of Antidepressant-Like Activity of Novel Water-Soluble Curcumin Formulations and St. John's Wort in Behavioral Paradigms of Despair

<i>Background:</i> Curcumin is the active principle of <i>Curcuma longa</i>, one of the widely used components in the traditional system of medicine in India. Despite its efficacy in experimental studies aiming at neuronal disorders like depression, curcu-min's poor water solubility challenges the production of therapeutic formulations. This study investigates the antidepressant-like activity of novel water-soluble curcumin formulations, dispensed in three different concentrations. Further, the study comparatively evaluates St. John's wort (SJW), another herbal preparation. <i>Methods:</i> These compounds were evaluated in the forced swimming test in mice, and the corresponding changes in the neurotransmitter levels were measured. <i>Results:</i> Three water-soluble curcumin formulations, C-5, C-20 and C-50 (50-200 mg/kg p.o.) decreased the immobility period, and increased serotonin and dopamine levels in the brain tissues. A subeffective dose (50 mg/kg) of these formulations enhanced the antidepressant-like effect of classical antidepressants with varied mechanisms of action. In addition, an SJW dose of 25 mg/kg showed a significant antidepressant-like effect in all the behavioral studies and also significantly increased brain neurotransmitter levels, especially that of serotonin. The effects produced by C-5 were comparable with those of SJW and fluoxetine, respectively. <i>Conclusion:</i> In all these observations, the water-soluble formulations showed a significant antidepressant-like effect, including enhancement of neurotransmitter levels as compared to the similar dose of a conventional curcumin preparation. Thus, these formulations may be used as a novel treatment option in the management of mental depression.