HPLC fingerprinting-guided determination of the optimal harvest period for Jinsi Huangju (Chrysanthemum morifolium Ramat.) and to elucidate its anti-inflammatory mechanisms.

'Jinsi Huangju' (JSHJ, Chrysanthemum morifolium Ramat.) is a medicinal plant traditionally used to manage inflammation. However, its optimal harvesting period and underlying anti-inflammatory mechanisms remain insufficiently explored. Therefore, this study aimed to investigate the effects of three JSHJ harvesting stages-initial flowering (CH), full flowering (SH), and final flowering (ZH)-on the bioactive compounds and to elucidate its anti-inflammatory mechanisms. The relative content of bioactive compounds (3,5-O-dicaffeoylquinic acid, chlorogenic acid, galuteolin) at each harvesting stage was determined using High-Performance Liquid Chromatography (HPLC, 1260, Agilent) fingerprints. The similarity of these fingerprints was then evaluated using the Chromatographic Fingerprint Similarity Evaluation System for Chinese Medicine (2004A edition). Anti-inflammatory activity was assessed in LPS-stimulated RAW 264.7 macrophages through MTT, Griess, and ELISA assays. The SH stage maximized JSHJ biomass and bioactive compounds. JSHJ extracts (20-50 µg/mL) significantly reduced LPS-induced levels of NO (from 9.45 to 0.16 µmol/L), TNF-α (from 127.26 to 8.09 pg/mL), and ROS. Among the extracts, petroleum ether (JSHJ-3) and ethyl acetate (JSHJ-4) exhibited the strongest anti-inflammatory effects. This study demonstrates that the SH stage is the most favorable harvest period for JSHJ, with extracts, particularly JSHJ-3/4, showing significant anti-inflammatory activity. These findings underscore the potential of JSHJ extracts as natural anti-inflammatory agents.