Research on the Improvement Effects and Mechanisms of Magnolia sieboldii Essential Oils on Insomnia in Mice

Insomnia is a common sleep disorder that is difficult to cure. Magnolia sieboldii essential oils (MSEOs) have been shown to have antidepressant effects, but there are few studies on treating insomnia. Therefore, this study aimed to investigate the therapeutic effects of MSEOs and to elucidate the molecular and neurophysiological mechanisms by which they alleviate insomnia. The main components of MSEOs extracted by steam distillation were analyzed by gas chromatography-mass spectrometry (GC-MS). To establish a p-chlorophenylalanine (PCPA)-induced insomnia model in mice, the levels of GAD65, GABAARα1, 5HT-2A, and 5HT-1A were detected by immunohistochemistry. The normal neurons in the mouse brain were counted by Nissl staining. RT-qPCR detected the relative mRNA expression levels of related genes in mice. A total of 69 components were identified by MSEOs, and the main components were β-elemene (19.94%), (Z)-β-ocimene (14.87%), and Germacrene D (7.05%). Different concentrations of MSEOs can successfully prolong the total sleep time and shorten the sleep latency of mice. GAD65, GABAARα1, 5HT-2A, and 5HT-1A levels still increased to varying degrees after treatment with different concentrations of MSEOs. Moreover, MSEOs could attenuate PCPA-induced neuronal death. At the same time, MSEOs enhanced the mRNA expression of 5HT-2A, GABAARα1, and GABAARγ2. MSEOs can extend sleep duration and reduce sleep latency in mice. MSEOs may demonstrate potential for treating insomnia by promoting neuronal proliferation in the brains of insomniac mice and upregulating the expression of GAD65, GABAARα1, 5HT-1A, and 5HT-2A proteins in various brain regions, potentially becoming an effective candidate for insomnia treatment.