Effects of drying methods on phenolic acids, flavonoids, and essential oils in three cultivars of Artemisia Argyi

This study systematically investigated how drying methods—non-defoliated sun drying (NSD), non-defoliated shade drying (NSHD), sun drying (SD), shade drying (SHD), hot-air drying (HD) at different temperatures, HD after fixation (FHD), and freeze drying (FD)—affect drying characteristics, flavonoid and phenolic acid content, essential oil yield, and composition of three Artemisia argyi cultivars: Qihui 1, Qiqing 1, and Qihuang 1. HD at 80 °C achieved the shortest drying time but the lowest essential oil yield. Non-defoliated drying remarkably increased phenolic acids and flavonoids. Essential oil profiles varied by cultivar and drying method. Compounds such as thujone, beta-selinene, and bornyl acetate emerged as key differentiating compounds. HD at 80 °C and FHD reduced oxygenated monoterpenes such as eucalyptol and thujone while increasing sesquiterpenes like caryophyllene and neointermedeol. In contrast, FD exhibited lower sesquiterpene hydrocarbons. Overall, our findings provide a foundation for optimizing the processing and application of A. argyi in healthcare and food sectors. • Drying without defoliation significantly increases flavonoid/phenolic acid content. • FD retains A. argyi ‘s phenolic acid compounds considerably. • Essential oil yield is negatively correlated with drying temperature. • Essential oil profiles vary among cultivars depending on drying method.