Early life stress and the effects of Chamaecyparis obtusa was the focus of a February 2014 Korean study. Chamaecyparis obtusa is a cypress species native to central Japan. It is sometimes called Japanese cypress or hinoki cypress and is a high-quality timber used especially in building temples in Japan such as the Osaka Castle and Horyuji Temple.
The essential oil of Chamaecyparis obtusa is believed to have an antidepressant effect and to be calming. The latter effect may have been the impetus for this essential oil animal study. Researchers at the School of Medicine, Kyung Hee University, Seoul, Korea, used maternal separation (MS) in rats and a microarray method to analyze changes in gene expression caused by the essential oil of Chamaecyparis obtusa (EOCO) in the hippocampus of the rats separated from their mothers.
One group of rats separated from their mothers was treated with Chamaecyparis obtusa essential oil, while a control group was untreated. Separated from the mothers on days 14 through 28 following birth, the treatment group was exposed to the essential oil for 1 or 2 hours by inhalation during the two weeks following separation.
A rat test called the elevated plus-maze was used to determine anxiety. The study reports that the essential oil-treated rats “showed decreased anxiety-related behaviors compared with the untreated MS rats. . . .”1
What was of great interest was the other effect of the cypress essential oil. We are grateful for the ever-useful Wikipedia for this description of the microarray analysis used in this study. “A microarray is a multiplexlab-on-a-chip. It is a 2D array on a solid substrate (usually a glass slide or silicon thin-film cell) that assays large amounts of biological material using high-throughput screening miniaturized, multiplexed and parallel processing and detection methods.”2
Using the microarray analysis, the researchers found that the essential oil of Chamaecyparis obtusa (EOCO) “downregulated the expressions of cytokine genes such as Ccl2, ll6, Cxcl10, Ccl19, and ll1rl in the hippocampus of MS rats, and [we] also confirmed that using reverse transcriptase—PCR. In particular, the expressions of Ccl2 and ll6 were predominantly decreased by EOCO in the hippocampus of MS rats.”3
That didn’t make much sense to us either! Just know that cytokines are a group of small proteins that are important in cell signaling. One study explained that “Cytokines, the chemical messengers between immune cells, play crucial roles in mediating inflammatory and immune responses. Cytokines also mediate signaling between cells of non-immune tissue including the nervous system and play important roles in both normal and pathology processes.”4
The cytokine genes that are involved in anxiety were downregulated, meaning they were dialed down, so to speak. The Korean study concluded that “these results indicate that EOCO decreases MS-induced anxiety-related behaviors, and modulates cytokines, particularly Ccl2 and ll6, in the hippocampus of MS rats.”5
It seems that this lovely Japanese cypress oil can calm separation anxiety in lab animals. The calming-influence claim of Chamaecyparis obtusa now has some new science behind it.
Park HJ, op cited.
Park HJ, op cited.