Inhaled essential oil from Chamaecyparis obtuse ameliorates the impairments of cognitive function induced by injection of beta-amyloid in rats

摘要

Context: Chamaecyparis obtusa Sieb. & Zucc, Endlicher (Cupressaceae) forest bathing or aromatherapy has been shown in various studies to have biological functions such as anticancer, antiallergies, antiinflammatory, and antioxidant activity. However, no reports exist on the pharmacological or biological activities of the essential oil of C. obtusa (EOCO) or its effects on central nervous system.Objective:The aggregation and formation of beta-amyloid peptides (Abeta) into fibrils are central events in the pathogenesis of Alzheimer's disease (AD), and overproduction and aggregation of Abeta into oligomers have been known to trigger neurotoxicity. In this study, we investigated the effects of inhaled EOCO on cognitive function and neuronal apoptosis in rats intrahippocampally injected with Abeta. Materials and methods: To model AD, 4 ug of aggregated Abeta was injected into the hippocampus. To test the effects of EOCO, behavioral performance in the Morris water maze was tested 4 days after injection. After behavioral testing, brain sections were prepared for TTC staining and TUNEL assay. Results: Inhaled EOCO protected spatial learning and memory from the impairments induced by beta_(1-40) injection. In addition, the behavioral deficits accompanying Abeta_(1-40)-induced AD were attenuated by inhalation of EOCO. Furthermore, acetylcholinesterase (AChE) activity and neuronal apoptosis were significantly inhibited in rats treated with Abeta_(1-40)0 and EOCO compared to rats treated only with Abeta_(1-40).Discussion and conclusion: EOCO suppressed both AD-related neuronal cell apoptosis and AD-related dysfunction of the memory system. Thus, the results of this study support EOCO as a candidate drug for the treatment of AD.