Background
Appropriate conditions for storage of Artemisia argyi leaves reduce irritation during treatment and increase the active ingredient content. Naturally aged A. argyi leaves (≥1 year) are optimal for moxibustion; however, this process is time-consuming and costly. A comprehensive understanding of the conditions for artificial aging of A. argyi leaves and the mechanism of quality-marker conversion are required to guarantee A. argyi quality and moxibustion efficacy.
Conclusion
Conditions for artificial aging of A. argyi leaves were identified for the first time, and the equivalent efficacy of artificially aged A. argyi leaves and naturally aged A. argyi leaves for improving UC was confirmed. This method for artificial aging of A. argyi leaves not only reduces the time and cost associated with this process, but also provides technical support to ensure the quality and stability of artificially aged A. argyi leaves. In addition, caffeic acid was identified as a potential quality-marker for establishing standards and specifications for aging A. argyi leaves for the first time, and its possible transformation mechanism was preliminarily elucidated.
Objective
To identify the optimal conditions for artificial aging of A. argyi leaves and clarify the mechanism of quality-marker conversion. Method: Gas chromatography (GC), high-performance liquid chromatography (HPLC), colorimeter (CD), and near-infrared spectroscopy (NIRS) were used to determine the chemical composition of A. argyi leaves before and after artificial and natural (1 year) aging and to determine the optimal artificial aging conditions. The effects of both artificially and naturally aged A. argyi leaves were then evaluated in a mouse model of ulcerative colitis (UC). The main chemical components of aged A. argyi leaves were then analyzed to determine quality-markers and the transformation mechanism.
Results
Comprehensive analysis of volatile and non-volatile components, color values, and characteristic near-infrared spectra revealed that the quality of artificially aged A. argyi leaves was similar to that of naturally aged A. argyi leaves. In the mouse model, artificially and naturally aged A. argyi leaves not only improved the symptoms of UC with the same therapeutic effects, but also safeguarded the barrier of the colonic mucosa and prevented the release of colitis-related substances. In addition, the content of caffeic acid converted from L-phenylalanine in A. argyi leaves increased during the aging process.