Abstract: [Objective] To provide a theoretical basis for utilizing the resources of Chimonanthus plants, the volatile components among 5 species of Chimonanthus were compared to understand genetic relationship and system classification of them.[Method] The samples were treated by head space solid phase micro-extraction (HS-SPME) and the pretreatment conditions were optimized. Combined with gas chromatography-mass spectrometry (GC-MS) technology, the volatile components from dry flowers of 5 species of Chimonanthus were determined, and the difference of them was compared. Then, SIMCA-P+11.0 software was applied to conduct the principal component analysis (PCA) of the 5 species of Chimonanthus dry flowers. According to the score diagrams, the relationship among the 5 species of Chimonanthus was visually presented.[Result] By optimizing treatment conditions of the samples, the best extraction conditions of SPME were 1.2 g of sample weight, 45 min of adsorption, 3 min of desorption, 70℃ of heating temperature. By GC-MS qualitative analysis, 46 volatile components were identified from the 5 species, and Ch. praecox contained 37 components, and there were 41 components existed in both Ch. grammatus and Ch. nitens, Ch. zhejiangensis and Ch. salicifolius contained 43 and 36 components respectively, and there were 24 common components among the 5 species. For the identified components, terpenoids were the main volatile composition of the Chimonanthus flowers, including oxygen derivatives (terpenes, terpene alcohols, terpene esters) and a handful of aliphatic compounds. The compounds of acetic acid linalool ester, denderalasin, caryophyllene oxide from Ch. praecox flower were the main components; The main compounds of Ch. nitens, Ch. salicifolius and Ch. zhejiangensis flowers were α-myrcene, eucalyptol, hedycaryol. As for Ch. grammatus, the components of eucalyptol, denderalasin, isoaromadendrene epoxide were rich. According to the PCA results, the 5 species of Chimonanthus were obviously divided into three categories. As for Ch. nitens, Ch. salicifolius and Ch. zhejiangensis flowers, the composition and contents of the volatile components were similar, so these 3 species were grouped in the same category. In addition, the composition of the volatile of Ch. praecox and Ch. grammatus differed a lot, so they were divided into the other two different categories. The PCA results were consistent with the results of previous studies of systematics of the 5 species.[Conclusion] The main volatile components of flowers of the 5 Chimonanthus species are terpenoids, and the differences among the 5 species were great. The volatile components from Ch. nitens, Ch. salicifolius and Ch. zhejiangensis flowers are similar, so they possess the same use value. However, the aroma of Ch. grammatus and Ch. praecox is different, and the volatile components of them were distinctly different from those of the other 3 species, so the use value of them should be discriminatory. This study provides a theoretical basis for classification of the 5 species of Chimonanthus and for the development and utilization of Chimonanthus flowers.

Key words: Chimonanthus, flower, volatile components, HS-SPME, GC-MS