Antidepressant effect of helicid in chronic unpredictable mild stress model in rats

Helicid (4-formylphenyl-β-D-allopyranoside) is a bioactive constituent of Helicid nilgirica Bedd that has been used in Chinese traditional herbal medicine to treat headache, insomnia, and depression. However, the underlying mechanisms of these effects are unclear. We have now investigated the effect of helicid on depression-related behaviors in rats exposed to chronic unpredictable mild stress (CUMS) and have also explored possible underlying mechanisms that involve neurotrophin expression. After 6 weeks isolation, body weight and sucrose preference were significantly reduced in rats with CUMS-induced depression compared with controls. The CUMS rats also showed significant inhibition of locomotory parameters in open field tests (involving behavioral assays). Helicid significantly regulated levels of corticosterone (CORT), inflammatory cytokines and 5-hydroxytryptamine (5-HT). Helicid also reversed CUMS-induced decreases of 5-HT1A receptor expression and promoted brain derived neurotrophic factor (BDNF) expression in the hippocampus The significant reversal of depressive-like behaviors by helicid is similar to that achieved by fluoxetine. The antidepressive effects are likely attributable to the promotion of hippocampal neurotrophin expression through activation of the serotonergic system. Helicid thus has potential for treating depressive disorders.