The exogenous factors of skin aging are mainly photoaging caused by ultraviolet radiation (UVR)(Krutmann et al., 2021). UVR can trigger skin cell senescence and inflammatory states, causing keratinocytes, fibroblasts and melanocytes to secrete senescence-associated secretory phenotype (SASP) factors such as cytokines, chemokines and matrix metalloproteinases (MMPs)(Vizioli and Adams, 2016). Although ultraviolet B (UVB) accounts for 5% of UVR, it produces more biological effects than ultraviolet A (UVA)(Slominski et al., 2018). It is mainly absorbed by the epidermis of the skin and causes intense photodamage. Repeated exposure of skin cells to UVB produces a large number of reactive oxygen species (ROS), which triggers a state of cellular oxidative stress(Skobowiat et al., 2017). It causes abnormal processes such as cell damage, apoptosis and dermal extracellular matrix (ECM) degradation, thereby accelerating photoaging. In addition, UVB directly damages DNA and disrupts cell cycle-related genes, thus increasing the risk of skin cancer(Yang et al., 2019). Therefore, it is necessary to take appropriate measures to delay exogenous aging.

Most researches now focus on the photoprotection of phytochemicals by resisting photoxidative stress, regulating ultraviolet induced signal transduction and promoting extracellular matrix remodeling(Bosch et al., 2015). For example, trans-cinnamic acid regulates the expression of antioxidant enzymes by activating NF-E2-related factor 2 (Nrf2) to combat oxidative damage caused by ultraviolet and help skin cells maintain normal function(Hseu et al., 2018). In addition, photoaging has intricate relationships with signaling pathways such as MAPK/activator protein 1 (AP-1) and nuclear factor kappa-B (NF-κB)(D. D. Xu et al., 2022). MAPK is the most studied class of kinases as intermediate messengers for skin ultraviolet radiation and MMPs expression(Duan et al., 2019). MMPs degrade various protein substrates in ECM, including collagen and elastin, resulting in sagging skin and wrinkles(Liu et al., 2019). Therefore, phytochemicals act on biochemical signaling pathways to exert a wide range of photoprotective activities.

Chrysanthemum morifolium Ramat. is a medicinal and food homologous plant with traditional effects such as anti-inflammatory, antifebrile, antibacterial and antiviral. Dried processed products of buds of chrysanthemum have become commercial and increasingly popular in the market in recent years(Yang et al., 2022). Some studies have shown that buds of chrysanthemum have excellent antioxidant, anti-inflammatory, analgesia and other effects(Zhang et al., 2022). However, there is no sufficient evidence for their antiphotoaging effects. Thus the extract of buds of chrysanthemum (CE) was prepared and analyzed in this study. This article aims to explore whether CE has the potential as a natural source antiphotoaging agent and investigate its mechanism.