Chemical characterization and discovery of anti-inflammatory components and their mechanism from <i>Artemisia argyi</i> leaves by UPLC-Q/TOF-MS, spectrum-effect relationship analysis, and MAPK pathway

Artemisia argyi is a high-value herbaceous plant in the Artemisia genus, and its leaves are commonly used in medicine and aromatic products. A. argyi leaves are a traditional herbal medicine used to treat inflammation, abdominal pain, hemorrhage, and dysmenorrhea. Several studies have reported that the A. argyi leaves extract exhibited significant anti-inflammatory activities, the components and mechanism of which remain uncovered. The study aimed to reveal these components and their mechanisms by ultra performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-Q/TOF-MS), chemical fingerprint, spectrum effect relationship, and mitogen-activated protein kinase (MAPK) pathway. Firstly, UPLC-Q/TOF-MS was employed to characterize secondary metabolites in A. argyi leaves, and fifty secondary metabolitesx, including 15 phenolic acids, 29 flavonoids, five coumarins, and one terpene were identified. The chemical fingerprint of A. argyi leaves was established using high performance liquid chromatography (HPLC), and 13 secondary metabolites were identified as common components. The contents of the 13 secondary metabolites in different batches of A. argyi leaves were simultaneously determined. The anti-inflammatory capacities of different batches of A. argyi leaves were evaluated using the lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophage inflammation model. The spectrum-effect relationship analysis was applied to investigate correlation between main secondary metabolites and anti-inflammation, and five metabolites, including 3-caffeoylquinic acid, 3,5-dicaffeoylquinic acid, 3,4-dicaffeoylquinic acid, schaftoside, and rutin were explored as latent anti-inflammatory compounds. The five selected metabolites exhibited remarkable inhibition of NO, IL-6, IL-1β, and tumor necrosis factor-α (TNF-α), and 3,5-dicaffeoylquinic acid and schaftoside had relatively great anti-inflammatory capacities. The western blot results indicated that 3,5-dicaffeoylquinic acid and schaftoside could reduce inflammation by inhibiting phosphorylation levels of p38, extracellular signal regulated kinase (ERK), and c-Jun N-terminal kinase (JNK) in the MAPK pathway. This work provided a thorough understanding of anti-inflammatory components of A. argyi leaves and their mechanism and also provided evidence for the utilization of A. argyi leaves as anti-inflammatory ingredients in medicinal products.