Rapid Discrimination Of Cinnamomum Camphora Chemotypes Based On Direct Mass Spectrometry

A chemotype is a chemically distinct entity in a plant,with difference in the composition of chemical components. The chemotypes of the plants are not morphologically enough to classify them. The phenomenon is a kind of biological diversity in plant species.Being a species of Cinnamomum, Lauraceae, Cinnamomum camphora(L.) Presl is of high economic value. C. camphora is a valuable tree disituated in the south of Yangtze River. It can be further divided into different chemotypes according to the main chemical components of essential oil: linalool-type, camphora-type,cineole-type, isoborneol-type, borneol-type, et al. This paper introduced characteristic and value of differencet chemotype C. camphora. We summarized the traditional methods to discriminant chemotypes of C. camphora, and describe innovative methods in this study. In this paper, the static headspace gas phase chromatography-mass spectrometry(SHS-GC-MS) was used to identify the volatile constituents in powder samples of C. camphora firstly. Then the surface desorption atmospheric pressure ionization mass spectrometry(DAPCI-MS) was used to detect camphor powder samples and fresh camphor leaves combined with multivariate analysis methods, respectively. The main results are as follows:(1) Total of 25 samples of C. camphor leaves, 5 for each chemotype, were tested by using SHS-GC-MS. 171 volatile components were analyzed qualitatively and quantitatively. We found 8 compounds were in all samples: β-linalool, camphene,β-guaiene, γ-terpinene, α-thujene, 2-ethyl-furan, α-caryophyllene and D-germacrene.Different chemotypes of C. camphora leaves were characterized with different quantities of chemical components. The results of CA and DA: β-guaiene,2-ethyl-furan, α-caryophyllene, D-germacrene, δ-cadinene, hexanal, and copaene were important discriminating variables to identify the five chemotype, which could be better distinguished by the 12 volatiles as well. The accuracy of CA was 92%, and the accuracy of DA was100%.(2) DAPCI-MS was selected to detect five chemotypes of C. camphora leaves powder, in the positive ion mode, and the raw mass spectral ?ngerprints of the powder samples were obtained. The results showed that the contribution rate of PC1,PC2, PC3 were 79.9%, 12.9% and 4.2%, a total of 97% in PCA. The accuracy of discrimination of CA and back propagation artificial neural network technology(BP-ANN) of DAPCI-MS was 100%. It demonstrated this method was distinguished chemotypes of C. camphora.(3) DAPCI-MS was selected to detect five chemotypes of C. camphora fresh leaves, and the raw mass spectral ?ngerprints of fresh leaves were obtained in the positive ion mode. The results showed that the chemotypes could be distinguished effectively combined with PCA and CA. The contribution rate of PC1, PC2, PC3 were 7 23.1% and 21.9%, 76.3%, a total of 76.3% in PCA. CA analysis was achieved effective distinction of different chemotypes of fresh camphor tree leavesIn this paper, we identified the marking compositions of five chemotypes of C.camphora leaves by using SHS-GC-MS. Then we used home-made DAPCI mass spectrometry as a research platform, which gave a systematic study of different chemotypes of C. camphora leaves powder and fresh leaves. A new method was established for a simple, rapid, sensitive detection of chemotypes of C. camphora. In the field of plant chemotype, this method is innovative and has application value.With the development of the miniaturization of the mass spectrometer, the method is expected to discover elite cultivars in field rapidly.