Antidepressant effect of Hedyotis corymbosa extract in olfactory bulbectomy rats

Background: Hedyotis corymbosa Linn. (family: Rubiaceae) has been used in the Indian indigenous system of medicine, Ayurveda, for treatment of various health aliments. Objectives: The present study was undertaken to evaluate the antidepressant activity of methanolic extract of whole plant of H. corymbosa (MHC) in olfactory bulbectomy rats. Materials and Methods: MHC was prepared and standardized to gallic acid by high-performance thin-layer chromatograph method. Effects of 14 days oral treatment of fluoxetine (30 mg/kg) and three doses of MHC (50, 100, and 200 mg/kg) were evaluated on olfactory bulbectomy (OBX)-induced alterations in behavioral and biochemical parameters in rats. Results: MHC treatment reversed the OBX-induced behavioral abnormalities such as increased exploratory activity in open-field paradigm and decreased feeding latency time in novelty-suppressed feeding test. Serum cortisol levels were restored near to normal by the MHC treatment. Further, treatment of MHC prevented the OBX-induced decline of brain levels of serotonin and nor-adrenaline in dose-dependent manner. Conclusion: MHC prevents behavioral and neurochemical changes in OBX-induced depression in rats. These results demonstrate the antidepressant effect of H. corymbosa and support its folklore claim. Abbreviations Used: ANOVA: one-way analysis of variance; CPCSEA: Committee for the Purpose of Control and Supervision of Experiments on Animals; ELIZA: Enzyme-linked immunosorbent assay; HPTLC: High-performance thin-layer chromatography; MHC: Methanolic extract of Hedyotis corymbosa; NA: Noradrenaline; OBX: Olfactory bulbectomy; SEM: Standard error of mean; TLC: Thin layer chromatography; 5-HT: 5-hydroxytryptamine; 5-HIAA: 5-hydroxyindoleacetic acid.