Artemisiae Argyi Folium, the dried leaves of Artemisia argyi, has been widely used in traditional Chinese and folk medicines for a long time. Qiai is one of the top-geoherb of Artemisiae Argyi Folium. Qiai contains various bioactive constituents, such as volatile oils, phenolic acids, flavonoids and terpenoids. Phytochemical studies demonstrated that volatile compounds are the main bioactive constituents in Qiai. Try to investigate dynamic changes of volatile components of Qiai from different harvest time and explore the optimum harvest time of Qiai, in this study, the contents of total volatile oils in Qiai collected from five different harvest time were analyzed by steam distillation method. The results showed that the contents of volatile oils of Qiai were higher in the third harvest time(around the Dragon Boat Festival), which is basically consistent with the traditional harvest time. Furthermore, a sensitive method based on gas chromatography-mass spectrometry(GC-MS) was established for qualitative analysis of volatile compounds in Qiai, and a total of thirty volatile compounds were identified. Chemometrics methods including principal component analysis(PCA) and orthogonal partial least-squares discriminate analysis(OPLS-DA) were applied to explore chemical markers and dynamic changes of volatile components in Qiai from different harvest time, and the results indicated that there were obvious differences in the relative contents of volatile compounds of Qiai samples from different harvest time. Eight volatile compounds, including α-terpinene, γ-terpinene, D-camphor, trans-carveol, α-copaene, isobornylisobutyrate, humulene, and caryophyllene oxide were selected as potential chemical markers. Among the eight chemical markers, the relative contents of α-terpinene, γ-terpinene, α-copaene and caryophyllene oxide were higher in the third harvest period(around the Dragon Boat Festival), which is consistent with the contents of total volatile oils. The present study could provide the basis for investigating the optimum harvest time of Qiai, and might be useful for the quality control of this herbal medicine.
Keywords: Qiai; harvest time; orthogonal partial least square-discriminate analysis; principal component analysis; volatile oil.