Quality formation in Codonopsis roots during post-ripening revealed by untargeted metabolomics

Codonopsis root is widely recognised as a plant with medicinal applications across various Asian countries. According to traditional treatment, Codonopsis roots may undergo a post-ripening phase to improve their therapeutic efficacy and commercial value. However, the underlying metabolic mechanisms driving quality formation during this process remain poorly understood. In this study, untargeted metabolomics was employed to investigate dynamic metabolite changes throughout the post-ripening. The findings indicate how post-ripening contributes to the quality of Codonopsis roots and reveal its close association with osmotic stress induced by dehydration. Over 2000 metabolites were identified, with fatty acid, amino acid, and carbohydrate metabolism actively involved in quality formation. Furthermore, both elevated temperature and kneading treatments were found to modulate metabolic changes during post-ripening by intensifying osmotic stress, thereby exerting a positive effect on the quality formation of Codonopsis roots. In addition, based on metabolomics data and insights from phenylpropanoid glycoside metabolism and the crepenynate pathway, dynamic regulatory mechanisms underlying the biosynthesis of key bioactive metabolites, including polyacetylenes and tangshenoside I, were systematically analysed. This study provides mechanistic insights into the metabolic basis of quality formation in Codonopsis root and offers a theoretical foundation for optimising post-harvest treatment to improve product quality and commercial value. • Post-ripening plays a key role in the quality formation of Codonopsis roots. • High drying temperature and kneading significantly modulated metabolite dynamics. • Osmotic stress is hypothesised to drive key metabolic changes during processing. • Hypothetical pathways of polyacetylenes and tangshenoside I were proposed.