Effects of aqueous extracts and volatile oils prepared from Huaxiang Anshen decoction on p-chlorophenylalanine-induced insomnia mice

Abstract

Ethnopharmacological relevance: Insomnia occurs frequently in modern society, and its common symptoms include difficulty in falling asleep and decreased sleep quality and time, memory, and attention. With the advantages of having few side-effects and reduced drug-dependence, a compound traditional Chinese medicine (TCM) prescription called Huaxiang Anshen Decoction (HAD) has been widely used in clinical practice in China mainly for primary insomnia treatment. Although the effects of volatile oils from TCM herbs have been increasingly reported, volatile oils in HAD are conventionally neglected because of its preparation process and clinical usage. Therefore, exploring the anti-insomnia effects of volatile oils from HAD is of great importance.

Aim of the study: The sedative and hypnotic effects of the conventional aqueous extracts, the volatile oils from HAD, and their combinations were investigated.

Methods: The main components in HAD volatile oils (HAD-Oils), were analyzed through gas chromatography-mass spectrometry (GC-MS). The HAD volatile oil inclusion complex (HAD-OIC) was prepared with β-cyclodextrin, and characterized. P-chlorophenylalanine (PCPA) was used to induce insomnia mice model and the test groups of HAD aqueous extract (HAD-AE), HAD-OIC and their combination (AE-OIC). An open field test was used in evaluating the mice's activities, and the levels of 5-hydroxytryptamine (5-HT) in mice sera, glutamate (Glu) in the hypothalamus, and γ-aminobutyric acid (γ-GABA) and dopamine (DA) in the brain tissues were assayed by enzyme-linked immunosorbent assay (ELISA).

Results: A total 74 components in HAD-Oil were determined by GC/MS, and cyperenone (20.46%) and α-cyperone (10.39%) had the highest relative content. The characterization results of the physical phase showed that volatile oils were successfully encapsulated by β-cyclodextrin and HAD-OIC was produced. The average encapsulation rates of cyperenone and α-cyperone were 79.93% and 71.96%, respectively. The results of pharmacology study showed that all the test groups increased the body weight and decreased voluntary activity when compared with the model group (P < 0.05). The HAD-AE, HAD-OIC, and AE-OIC groups increased the levels of 5-HT in the sera and DA and Glu/γ-GABA in the brains, and AE-OIC groups showed better performance than the other test groups.

Conclusions: HAD-Oil exerts sedative and hypnotic effects, which are increased when it is used with HAD-AEs. This result provides a favorable experimental evidence that volatile oils should be retained for the further development of HAD.

Keywords: Huaxiang Anshen Decoction; Sedative and hypnotic effects; Volatile oil; β-cyclodextrin inclusion complex.