Comparative Analysis of Volatile Components in Commercial Japanese Hinoki Cypress (Chamaecyparis obtusa) Essential Oils

Abstract

Hinoki cypress (Chamaecyparis obtusa) is an evergreen conifer endemic to Japan. The benefits of hinoki fragrance for the central nervous system have garnered increasing attention, and its inhalation is gaining popularity. While hinoki essential oils are available from various manufacturers, the growing regions of the trees and plant parts used for extraction differ among products, and the characteristic benefits of each product are not clearly defined. In this study, we performed gas chromatography with flame ionization detection (GC-FID) and GC-MS analysis on ten commercial hinoki essential oils, one from leaf and nine derived from wood, to examine differences in volatile components between plant parts and among wood-derived samples. The results showed that sabinene, bornyl acetate and α-terpinyl acetate were the major components in leaf-derived oils, while α-pinene and δ-cadinene predominated in wood-derived oils. Among the wood-derived samples, the ratio of α-pinene to δ-cadinene was categorized into three distinct patterns: samples with higher α-pinene content, samples with higher δ-cadinene content, and samples in which both components were present in nearly equal amounts. Differences in chemical composition and the relative proportion of components may influence the physiological effects of hinoki essential oil. Evaluating how these variations affect health benefits could contribute to product quality assessment and help establish tailored applications for each specific chemical profile.