[Effects of different drying methods on content of main chemical compounds in Callicarpae Nudiflorae Folium]

This study aims to identify the main chemical compounds, investigate the effects of different drying methods on the quality, and determine the appropriate drying method of Callicarpae Nudiflorae Folium. UPLC-UV-Q-TOF-MS was employed to characterize and identify 35 main compounds, including phenylethanoid glycosides, flavonoids, and iridoids in Callicarpae Nudiflorae Folium. A method for the simultaneous determination of 8 compounds with strong UV absorption and high content was established to evaluate the quality of Callicarpae Nudiflorae Folium dried by different methods. UPLC-UV-Q-TOF-MS combined with principal component analysis(PCA) was employed to compare the Callicarpae Nudiflorae Folium samples treated by microwave drying at different power(119, 231, and 385 W), drying in the shade, sun drying, and oven drying at different temperatures(50, 60, 70, 80, 90, and 100 ℃). The total content of decaffeoyl acteoside, picroside Ⅲ, galuteolin, forsythin B, acteoside, isoacteoside, 6-hydroxyluteolin-7-glucoside, and caffeic acid in Callicarpae Nudiflorae Folium, as well as the content of most compounds, decreased with the rise in drying temperature and with the decrease in microwave power. Considering the content of compounds, low carbon, and energy saving, microwave drying at 231 W, low-temperature drying, or natural drying is recommended for the production of Callicarpae Nudiflorae Folium. This study provides a scientific basis for the selection of drying methods for Callicarpae Nudiflorae Folium at the place of origin and for the improvement of quality standards.