Extraction of polyphenols from Chrysanthemum morifolium Ramat. leaves

Chrysanthemum morifolium Ramat. ‘Hangbaiju’ is a widely cultivated, economically important plant in China. During the harvesting of its capitula, the leaves, which have long been underutilized by-products, are found be rich in valuable polyphenols with beneficial bioactivities. Motivated by the green economy concept, our team focused on steam explosion (SE) to extract high-value phenolic compounds from Hangbaiju leaves. The research findings indicated that SE pretreatment led to a remarkable increase in the total phenol and flavonoid content in Hangbaiju leaves (26.32 mg CAE/g and 30.72 mg RE/g, respectively), with an increase of more than three-fold. This also enhanced antioxidant capacity and laid a solid foundation for the development of antioxidant products. Notably, 3,4-di-O-caffeoylquinic acid, undetectable in raw leaves, was present in the SE-treated leaves at a concentration of 1.22–4.23 mg/g. Additionally, the yields of 4-O-caffeoylquinic acid, acacetin, and apigenin also increased significantly. Furthermore, the SE-treated Hangbaiju leaves exhibited a high bioaccessible phenolic content after simulated gastric digestion, supporting their use in functional foods and supplements. In conclusion, this research validates the feasibility and effectiveness of SE in the pretreatment of Hangbaiju leaves. It enables the utilization of Hangbaiju leaf residues as resources, alleviates environmental pressure, and clears the path for the development of high-value-added products, thereby making a substantial contribution to the future growth of the green economy. • An efficient extraction method for polyphenols from Hangbaiju leaves was proposed. • Steam explosion significantly increased the total phenol and flavonoid contents. • A notable rise in 4-CQA, 3,4-CQA, apigenin, and acacetin was observed.