Abstract
The quantitative comparison of essential oils extracted from various parts of Cupressus funebris and Juniperus chinensis was studied. With increased height, the content of essential oils from branches decreased, while the content of essential oils from leaves increased for both species. A maximum amount of essential oils were found in the west and a minimum in the east of branches and leaves for the two species. Moreover, the content of essential oils in trees with a knot was higher than in those without a knot. The order of essential oil content was as follows: leaf > fine root > coarse root > bark > bough > branch > trunk in C. funebris, and leaf > fine root > bark > coarse root > bough > trunk > branch in J. chinensis. The essential oils extracted from various parts of C. funebris and J. chinensis were analyzed by gas chromatography-mass spectrometry. A total of 67, 33, 69, 65, and 69 components were identified from the roots, trunks, barks, branches, and leaves of C. funebris, respectively. A total of 72, 46, 79, 55, and 82 components were identified from the roots, trunk, bark, branches, and leaves of J. chinensis, respectively.
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Distribution and Composition Analysis of Essential Oils Extracted from Different Parts of Cupressus funebris and Juniperus chinensis
Jianhua Lyu,a,b,§ Junqi Zhao,a,§ Jiulong Xie,a Xianwei Li,a,* and Ming Chen a,b,*
The quantitative comparison of essential oils extracted from various parts of Cupressus funebris and Juniperus chinensis was studied. With increased height, the content of essential oils from branches decreased, while the content of essential oils from leaves increased for both species. A maximum amount of essential oils were found in the west and a minimum in the east of branches and leaves for the two species. Moreover, the content of essential oils in trees with a knot was higher than in those without a knot. The order of essential oil content was as follows: leaf > fine root > coarse root > bark > bough > branch > trunk in C. funebris, and leaf > fine root > bark > coarse root > bough > trunk > branch in J. chinensis. The essential oils extracted from various parts of C. funebris and J. chinensis were analyzed by gas chromatography-mass spectrometry. A total of 67, 33, 69, 65, and 69 components were identified from the roots, trunks, barks, branches, and leaves of C. funebris, respectively. A total of 72, 46, 79, 55, and 82 components were identified from the roots, trunk, bark, branches, and leaves of J. chinensis, respectively.
Keywords: Essential oils; Cupressus funebris; Juniperus chinensis; Chemical composition; Distribution
Contact information: a: College of Forestry, Sichuan Agricultural University, Chengdu 611130, China; b: Sichuan Provincial Colleges and Universities Wood Industry and Furniture Engineering Key Laboratory, Sichuan Agricultural University, Chengdu 611130, China;
* Corresponding authors: lxw@sicau.edu.cn; chenming@sicau.edu.cn
§ These authors contributed equally to this work.
INTRODUCTION
The genus Cupressus, which belongs to the family Cupressaceae, originated in the Mediterranean region and includes approximately 17 species distributed in the southern part of North America, East Asia, and Mediterranean region. In China, there are nine species and one variety, out of which four species are endemic to China. Cupressus funebris is one of these four endemic species (Fu et al. 1999). Juniperus chinensis is an ornamental plant that also belongs to the family Cupressaceae (Hora 1981), which has more than 100 cultivars.
Most of the research literature focuses on forest resource management and biodiversity, while only a few of them discuss the essential oils of C. funebris and J. chinensis (Zheng et al. 2011; Hou et al. 2013; Li et al. 2015). The current research on essential oils extracted from Cupressus funebris and Juniperus chinensis includes some detailed reports of the chemical constituents of these essential oils. Pierre-Leandri et al. (2003) and Duquesnoy et al. (2006) found 59 and 46 compounds, respectively, in the oils of C. funebris, while Pu and Huang (1999) and Raina et al. (2005) found and identified 34 and 33 compounds, respectively, in the oils of J. chinensis. However, most of these studies focused on studying the biological pest control and biological and antimicrobial activities of the major constituents of essential oils from C. funebris and J. chinensis (Dolan et al. 2007; Lee et al. 2009; Carroll et al. 2011; Giatropoulos et al. 2013). Only a few studies have been conducted in terms of the distribution of essential oils of C. funebris and J. chinensis. In other species like Pinus roxburghii, Laurelia sempervirens, Drimys winteri, Cinnamomum osmophloeum, and Litsea cubeba, research on the essential oils from different parts of the plants has been conducted (Cheng et al. 2006; Wang and Liu 2010; Zapata and Smagghe 2010; Salem et al. 2014).
The aim of this paper was: (a) to investigate the distribution of the essential oils from different parts of C. funebris and J. chinensis; and (b) to assess the chemical composition of the obtained essential oils from the different parts of C. funebris and J. chinensis.
EXPERIMENTAL
Materials
Cupressus funebris was collected from the Shiyang town of Dujiangyan, in the Sichuan province, China. The tree was 13 years old. Juniperus chinensis was collected from the Hesheng garden of Dujiangyan, Sichuan, China, and the height of the tree was taller than 3 m. After the logs were cut down, the branches and leaves of different heights and different directions were collected and returned to the laboratory for pulverization after air-drying.
The experimental material was grouped according to diameter of branches and roots, as follows: one-year branches and leaves, bough (diameter ≥ 2.0 mm), fine root (diameter ≤ 2.0 mm), and coarse root (diameter ≥ 2.0 mm). The crown of the tree was divided into trisections along the high direction, and the branches and leaves were harvested in each height interval.