Chemotaxonomic identification of Chamaecyparis formosensis Matsumura and Chamaecyparis obtusa var. formosana (Hayata) Rehder using characteristic compounds of wood essential oils

Abstract

Chamaecyparis formosensis Matsumura and C. obtusa var. formosana (Hayata) Rehder are important, precious, and well-known species grown in Asia. Renowned for excellent natural durability, their wood logs are regularly used as quality building materials or furniture. However, these two species have similar appearances, e.g., leaf, twig, wood, hardly distinguishable by the naked eye. The purpose of the present study is to phytochemically differentiate these two species using volatile compounds from the woods. Wood essential oils were obtained by 6-h hydrodistillation. The chemical composition was identified by GC-MS, and semi-quantification was carried out to determine the content of each compound. Furthermore, compounds with a significantly higher content than those of the other species were screened by t-test and principal component analysis (PCA). Results from semi-quantification and t-test showed that C. formosensis contained higher content of cis-myrtanol (ratio 37.1 ± 19.8), chamaecynone (11.0 ± 6.7), and α-eudesmol (8.5 ± 7.9), while C. obtusa var. formosana comprised mainly of α-terpineol (30.2 ± 10.1) and borneol (24.0 ± 16.1). Moreover, PCA results showed that the representative compounds of C. formosensis were cis-myrtanol and chamaecynone, while those of C. obtusa var. formosana were α-terpineol, borneol, and α-cadinol. Taken together, the above-mentioned results suggested significant compositional differences between these two species. For distinguishing the two kinds of wood, C. formosensis should be easily identified by its two characteristic compounds: cis-myrtanol and chamaecynone; while C. obtusa var. formosana could also be distinguished by its characteristic compounds: α-terpineol and borneol.