Abstract: Objective To determine the volatile constituents and their contents in the roots of 5 cultivated Angelica dahurica and one wild A. dahurica and analyze the chemical relationship among the plants of A. dahurica. Methods The essential oil was extracted from the roots of 5 cultivated plants of Angelica dahurica and one wild A. dahurica by water steam distillation. Gas chromatography-mass spectrometry (GC-MS) was used to separate and identify all the volatile oil components in the extracts, and their relative contents were calculated with area normalization method. We also conducted clustering analysis and principal component analysis of the volatile oil components. Results We identified a total of 81 compounds from the roots of the 6 plants of Angelica dahurica, including 27 in Chuanbaizhi (Angelica dahurica cv. 'Hangbaizhi'), 34 in Hangbaizhi (Angelica dahurica cv. 'Hangbaizhi'), 24 in Qibaizhi (Angelica dahurica cv. 'Qibaizhi'), 32 in Yubaizhi (Angelica dahurica cv.'Qibaizhi'), 28 in Bobahizhi (Angelica dahurica cv.'Qibaizhi'), and 34 in Xinganbaizhi (Angelica dahuirca). These compounds included, in the order of their relative contents (from high to low), alkanes, olefins, esters, organic acids and alcohols. Among the common components found in the roots of all the plants of A. dahurica, nonylcyclopropane, cyclododecane and hexadecanoic acid were identified as the volatile oil components that showed the highest relative contents. Clustering analysis of the volatile oil components showed that wild Angelica dahurica (Xing'anbaizhi) and the 5 cultivated Angelica dahurica (Chuanbaizhi, Hangbaizhi, Qibaizhi, Yubaizhi, Bobaizhi) could be divided into two groups, and the cultivated Angelica dahurica could be divided into two subgroups: Chuanbaizhi, Yubaizhi and Hangbahizhi were clustered in one subgroup, and Qibaizhi and Bobaizhi in another. The results of principal component analysis was consistent with those of clustering analysis. Conclusion The main volatile oil components and their contents vary among the 6 plants of A. dahurica. Nonylcyclopropane, cyclododecane and hexadecanoic acid are the most abundant volatile oil components in all the plants of A. dahurica, which can be divided into two clusters.

Key words: Angelica dahurica; volatile oil; chemical relationship; clustering analysis; gas chromatography-mass spectrometry