Antidepressant-like effect and phytochemical profile of supercritical CO₂ extract from Citri reticulatae pericarpium

Citri reticulatae pericarpium is a condiment, adding much flavor in Chinese food. Also it can be used to treat depression as a Traditional Chinese Medicine (TCM). The study here aimed to evaluate the antidepressant effect between the supercritical CO₂ extract (SC-E) from Citri reticulatae pericarpium and the essential oil extracted by steam distillation (SD-E). And chemical compositions of SC-E were qualitatively analyzed by ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF/MS) and gas chromatography-mass spectrometry (GC-MS). Compared with SD-E, SC-E showed a stronger antidepressant-like effect in FST and TST mice. And it also decreased the content of monoamine oxidase (MAO) in the cerebral cortex of stressed mice. A total of 60 compounds were identified in SC-E. Among them, 28 compounds were characterized in UPLC-Q-TOF/MS analysis and all are polymethoxyflavones (PMFs). Three main compounds, 3,5,6,7,8,3',4'-heptamethoxyflavone, nobiletin and tangeretin, together account for 66.09% of the total relative peak area. 33 terpenes were identified by GC-MS analysis, such as D-limonene (12.34%), β-elemene (8.86%), germacrene D (5.59%) and (Z, E)-α-farnesene (5.44%). Polymethoflavones and terpenes are the main constituents of SC-E responsible for its antidepressant-like effect. The study could stimulate further investigations into the antidepressant effects and mechanism of Citri reticulatae pericarpium.