This study aims to reveal the interannual and seasonal variations in functional components in Polygonatum cyrtonema Hua. rhizomes and evaluate whether the variations significantly affect the quality of rhizomes as a traditional Chinese herbal medicine. The interannual and seasonal variations in total flavonoid content and total saponin content were analyzed. The global dynamic variation in secondary metabolites in the rhizomes during a five-year growth period and in two traditional harvesting seasons were investigated based on metabolomics method. Results clearly showed that the functional components in P. cyrtonema rhizomes exhibited a significant increase in accumulation during the one- to four-year growth period and a significant decrease in accumulation during the four- to five-year growth period. The most active accumulation occurred during the three- to four-year growth period. Drastic variations in functional components occurred from spring to autumn. The significant interannual variation and drastic seasonal variation were strongly associated with the enrichment in some pathways related to the biosynthesis of secondary metabolites and the metabolisms of amino acids. The interannual and seasonal variations in functional components significantly affected the quality of P. cyrtonema rhizomes. The four-year-old rhizomes had the most superior quality due to their higher content of functional components and much more newly formed components. The rhizomes harvested in spring or autumn had unequal quality because of their significant differences in composition and content of functional components. Specifically, the rhizomes from spring contained more flavonoids, alkaloids, and phenolic acids, while those from autumn comprised more steroids. In conclusion, this study reveals that the interannual and seasonal variations in functional components can significantly affect the quality of P. cyrtonema rhizomes as a traditional Chinese herbal medicine. This study provides foundational insights and theoretical guidance for determining an optimal cultivation period to obtain medicinal rhizomes with superior quality. It also offers a strategy for harvesting medicinal rhizomes in two different seasons to achieve unequal quality.

The aims of this study were to explore the significant chemical changes in functional components induced by the traditional processing method and evaluate whether this method based on nine cycles of steaming and drying can effectively enhance the medicinal effects of Polygonatum cyrtonema rhizome. A global analysis on dynamic changes in secondary metabolites during nine processing cycles was performed, and the significantly differentially accumulated secondary metabolites were initially identified based on the secondary metabolome. Unsupervised principal component analysis (PCA), hierarchical clustering analysis (HCA), and orthogonal partial least squares discriminant analysis (OPLA-DA) on secondary metabolites clearly showed that processing significantly increased the global accumulation of secondary metabolites in processed P. cyrtonema rhizomes compared to unprocessed crude rhizomes. The first six processing cycles induced drastic changes in the accumulation of functional components, while the last three did not induce further changes. The accumulations of most functional components were significantly enhanced after the first three cycles and stabilized after six cycles; meanwhile, the first three cycles also led to numerous new components. However, the enhancing effects were unavoidably reversed or weakened under continued processing lasting 6–9 cycles. Furthermore, continued processing also reduced the contents of a small number of original components to undetectable levels. Processing induced some significantly enriched Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways, among which the first three processing cycles enhanced the synthesis of various secondary metabolites and significantly affected the metabolisms of amino acids. In conclusion, this study not only reveals that processing can effectively enhance the medicinal effects, by two main mechanisms including enhancing chemical synthesis and inducing structural transformation of functional components, but also provides theoretical guidance for the optimization of the traditional processing method based on nine cycles of steaming and drying for achieving optimal effects on enhancing the medicinal effects of P. cyrtonema rhizome.

This study aims to understand the functional component compositions of traditional herbal health beverages made from Polygonatum cyrtonema rhizomes and to reveal the pharmacodynamic chemical basis for their claimed health benefits. Two traditional methods, rhizome decoction and rhizome infusion, were used to make health herbal beverages, including “Huangjin” tea and “Huangjin” wine, respectively. The secondary metabolites of “Huangjin” beverages were investigated and compared by widely targeted metabolomics. The results clearly showed that the major functional components in “Huangjin” beverages were phenolic acids, flavonoids, and alkaloids. The “Huangjin” wine has a greater variety of flavonoids and alkaloids than “Huangjin” tea, and the functional components in “Huangjin” wine were more abundant than those in “Huangjin” tea. Homoisoflavones and amide alkaloids were the dominating flavonoids and alkaloids in “Huangjin” wine, respectively. Continuous rhizome infusion could not increase the content of functional components in “Huangjin” wine. In conclusion, this study not only provides primary evidence to support the claimed health benefits of “Huangjin” beverages but also suggests that making traditional herbal beverages by rhizome infusion has superior health benefits than making them by rhizome decoction, which is attributed to the higher yields of functional components extracted by Chinese liquor than hot water. Therefore, Chinese liquor shows advantages in its use as a superior binary ethanol–water solvent in making herbal health beverages to enhance the solubility of poorly water-soluble functional components.