Rapid antidepressant effects of Yueju: A new look at the function and mechanism of an old herbal medicine

Ethnopharmacological relevance Yueju is a traditional herbal medicine which consists of five herbs and formulated to treat depression-related syndromes 800 years ago. Yueju is still widely prescribed to treat conditions which include digestive dysfunction and depression. Recently, Yueju has been shown to promote a fast-onset antidepressant effect clinically and in preclinical studies. Because conventional antidepressants have a delayed onset in treating depression, the novelty of Yueju's rapid antidepressant effect and its underlying mechanism are of great significance both clinically and scientifically. Aim of the study To review the use of Yueju for treatment of mood-related syndromes, and particularly its use in depression. To evaluate recent evidence of Yueju rapid antidepressant actions, based on new findings at behavioral and molecular levels. To suggest direction for future studies to address further scientific issues. Materials and methods Reports regarding to the history and current use of Yueju are summarized. Recent progress on rapid antidepressant effects of Yueju, the crucial constituent, Gardenia jasminoides J.Ellis (GJ) and other herbs, are reviewed. Results The medical need for rapid antidepressant actions, as well as breakthrough findings using ketamine and its limitations are introduced. Studies with Yueju using a number of acute, subacute and chronic behavioral paradigms are compared with ketamine. Findings from clinical reports also support the rapid action of Yueju. Studies examine the contribution of the constituent herb GJ, in rapid antidepressant effects. Importantly, research into the mechanism of Yueju or GJ's antidepressant response indicate the importance of up-regulation in the neural circuit responsible for antidepressant activity, and highlight common and specific molecular signaling by Yueju that may explain why this herb formula has unique antidepressant activity. Conclusion Preclinical and clinical studies demonstrate that Yueju confers rapid antidepressant effects. The common mechanisms shared both for ketamine and Yueju, as well as the novel mechanism specific to Yueju are examined. Yueju and GJ may have great clinic applicability and further more detailed studies are warranted.