Objectives Cornus officinalis Sieb. et Zucc. pulp (COP) and Gardenia jasminoides Ellis fruit (GJF) are both medicinal and edible herbs with a good taste. Yuzhi Jieyu tea (YZJYT) is mainly prepared using COP and GJF teabags and boiling water. The present study aimed to investigate the antidepressant-like effects of YZJYT and its composition ratio in vivo for the first time.
Methods Male mice were treated with YZJYT (4 g/kg) at different ratios and fluoxetine hydrochloride (10 mg/kg) once a day for 7 consecutive days by intragastric administration. The forced swim test (FST), tail suspension test (TST), open field test (OFT) and reserpine reversal test 1 hour after the last administration were used to evaluate the antidepressant-like effects and the composition ratio of YZJYT, and brain tissues were used for serotonin determination through enzyme-linked immunoassay.
Results YZJYT (COP:GJF ratio ranging from 1:2 to 4:1) administration exerted antidepressant-like effects in mice, as indicated by the reduced duration of immobility in the FST and TST, but it had no effect on locomotor activity in the OFT. YZJYT treatment significantly counteracted the decrease in rectal temperature induced by reserpine. Furthermore, YZJYT increased levels of serotonin (5-HT) in the brains of mice. These antidepressant-like effects of YZJYT are essentially similar to the effects of the clinical antidepressant fluoxetine hydrochloride.
Conclusions These findings indicate that YZJYT exerts an antidepressant-like effect when the composition ratio of COP:GJF ranges from 1:2 to 4:1, and suggest its mechanisms may be partially involved in the central serotonergic system.
Acknowledgments This research was financially supported by project grants from the Funding Scheme for Young Key Teachers of Colleges and Universities in Henan Province (Grant No. 2014GGJS-072), the Science and Technology Project of Zhengzhou (Grant No. 20150309) and the Students’ Creative Learning project in Henan University of Chinese Medicine (Grant No. YXCX  3).