Analysis Of GC/MS And HPLC Fingerprint Of Different Osmanthus Fragrans Cultivars

Osmanthus fragrans,which is one of the traditional Chinese flowers,belongs to the genus Oleaceae in the classification of plant species.The earliest origin is in the southwestern part of China.It is often used as a greening tree and is also a medicinal material.At present,there are more than 160 varieties of O.fragrans found in the world.O.fragrans can be divided into five categories: Aurantiacus group,Albus group,Lutes group,Asiaticus group and Colour group.In this study,38 O.fragrans varieties(6 kinds of Aurantiacus,9 kinds of Albus,14 kinds of Lutes,9 kinds of Asiaticus)in Wuhan Huaguoshan Ecological Park were used as experimental materials.The volatile components in the petals were detected and analyzed by gas chromatography-mass spectrometry(GC/MS).The extract in the petals were tested by high performance liquid chromatography(HPLC)at a wavelength of 330 nm.The chromatographic fingerprint of O.fragrans was established using “similarity evaluation system for chromatographic fingerprint of TCM”.Subsequently,main component analysis,similarity analysis and cluster analysis were performed to explore the correlation in groups and varieties and to provide a new way for the classification and identification of varieties.The main findings of this study are as following:(1)GC/MS fingerprint of different O.fragrans varieties38 O.fragrans varieties were collected and processed,and the volatile components in O.fragrans were qualitatively and quantitatively determined by headspace solid phase microextraction(HS-SPME)and gas chromatography-mass spectrometry(GC-MS).Moreover,we classify and statistically analyze their main volatile components by previous studies.The results showed that there were no significant differences in the types of volatile components among the four major groups,but there were large differences in the types of volatile components and relative contents in the same group.In the four major groups of O.fragrans,the main types of the volatile components were alcohol,ketones,alkenes,esters,aldehydes and alkanes.Nine major volatile compounds,including Dihydro-?-ionone,linalool oxide ?-ionone Ionone,2,2,6-trimethyl-6-vinyltetrahydro-2H-furan-3-ol,?-terpineol,linalool,?-ionone,propidyl lactone,and n-Heptadecane,are determined by statistically comparing the types of components and relative contents in different varieties.The chromatogram of GC/MS was imported into the “similarity evaluation system for chromatographic fingerprint of TCM”,and the GC/MS fingerprints of different O.fragrans varieties were established with the peak time and relative content of different volatile components as the parameters,and the similarity analysis was carried out.Subsequently,cluster analysis of O.fragrans varieties in groups and varieties was performed using SPSS statistics.The results showed that 19,26,27 and 31 common peaks were identified in Aurantiacus group,Albus group,Lutes group and Asiaticus group respectively.Based on the similarity analysis of main components,the similarity ranges are 0.379~0.944,0.168~0.988,0.164~0.989 and 0.242~0.942 in Aurantiacus group,Albus group,Lutes group and Asiaticus group respectively.Overall,the similarity is low,which indicates that the volatile components of different varieties in the same group are different,and it also proves the GC/MS fingerprint was feasible for the identification of individual varieties of O.fragrans;the cluster analysis of the same group showed the correlation of different varieties of O.fragrans in the same group,which was basically consistent with the similarity.However,the cluster analysis in different group showed that different varieties of O.fragrans in different groups were interlaced into one group,indicating that there was no obvious correlation between the types and content of volatile components and the classification of varieties in O.fragrans.(2)HPLC fingerprint of different O.fragrans varietiesThe first flowering period of 44 O.fragrans varieties in the autumn of 2018 was recorded by field survey.The results showed that the early full-bloom stage was mainly concentrated from September 28 th to October 7th.The petal of different O.fragrans varieties was identified by “The Royal Horticultural Society's Color Chart”.The color range of Aurantiacus group is mainly between 7B~15B,with the mainly color of lemon yellow,medium yellow and yellow.The color range of Albus group is mainly between 3C~9C,with the mainly color of light lemon yellow and lemon yellow.The color range of the Lutes group is mainly between 21C~31C,with the mainly color of light orange-yellow,orange-yellow,orange,light orange-red,medium orange-red and orange-red.The color of Asiaticus group is mainly between 2C~ 9D,similar to Albus group,with the mainly color of light lemon yellow,lemon yellow and medium yellow.The high-performance liquid chromatograph(HPLC)was used to import the HPLC chromatogram into the “similarity evaluation system for chromatographic fingerprint of TCM”.The HPLC fingerprints of different varieties of O.fragrans were established with the peak time and relative content of different extract components as the parameters.Subsequently,the similarity analysis was carried out and cluster analysis of O.fragrans varieties in and between groups was performed using SPSS statistics.The results showed that there were 15,13,9,and 12 common peaks in Aurantiacus group,Albus group,Lutes group and Asiaticus group respectively.Moreover,extract in Lutes group were less than the other three groups.The similarity ranges of Aurantiacus group,Albus group,Lutes group and Asiaticus group were: 0.975~0.999,0.942~1,0.977~1,0.923~0.999.Overall,the similarity was high,indicating that the extract in different varieties of the same group differed little in content,and also indicating that the constructed HPLC fingerprint could not effectively identify the varieties of individual O.fragrans.The cluster analysis showed that the correlation between different varieties of O.fragrans in the same group is consistent with similarity.The cluster analysis also showed that the group of Lutes were obviously clustered in the same category and the other three varieties were clustered together.And there are obvious aggregations of the same variety in the locality,indicating that there are significant differences in the types and contents of extract between Lutes group and the other three groups.There are also population characteristics of O.fragrans in other three groups,which can be used for reference in the classification of groups.