The depletion of the ozone layer has intensified ultraviolet (UV) radiation exposure, leading to oxidative stress, DNA damage, inflammation, photoaging, and skin cancer. Medicinal plants, widely used in Traditional Herbal Medicine (THM), particularly in Traditional Chinese Medicine (TCM), have demonstrated significant therapeutic potential due to their well-characterized active compounds and established photoprotective effects. This review systematically evaluates 18 medicinal plants selected based on their traditional use in skin-related conditions and emerging evidence supporting their efficacy against UV-induced skin damage. Their bioactive components exert antioxidant, anti-inflammatory, DNA repair, and depigmentation effects by modulating key signaling pathways, including Nrf2/ARE-, MAPK/AP-1-, PI3K/Akt-, and MITF/TYR-related melanogenesis pathways. Moreover, novel drug delivery systems, such as exosomes, hydrogels, and nanoemulsions, have significantly enhanced the stability, bioavailability, and skin penetration of these compounds. However, challenges remain in standardizing plant-derived formulations, elucidating complex synergistic mechanisms, and translating preclinical findings into clinical applications. Future interdisciplinary research and technological advancements will be essential to harness the full therapeutic potential of medicinal plants for UV-induced skin damage prevention and treatment.

The transforming growth factor-βs (TGF-βs) are multifunctional cytokines capable of regulating a wide range of cellular behaviors and play a key role in maintaining the homeostasis of the immune system. The TGF-β subfamily, which is only present in deuterostomes, expands from a single gene in invertebrates to multiple members in jawed vertebrates. However, the evolutionary processes of the TGF-β subfamily in vertebrates still lack sufficient elucidation. In this study, the TGF-β homologs are identified at the genome-wide level in the reissner lamprey (Lethenteron reissneri), the sea lamprey (Petromyzon marinus), and the Japanese lamprey (Lampetra japonica), which are the extant representatives of jawless vertebrates with a history of more than 350 million years. The molecular evolutionary analyses reveal that the lamprey TGF-β subfamily contains two members representing ancestors of TGF-β2 and 3 in vertebrates, respectively, but TGF-β1 is absent. The transcriptional expression patterns show that the lamprey TGF-β2 may play a central regulatory role in the innate immune response of the lamprey since it exhibits a more rapid and significant upregulation of expression than TGF-β3 during lipopolysaccharide stimuli. The incorporation of BrdU assay reveals that the lamprey TGF-β2 recombinant protein exerts the bipolar regulation on the proliferation of the supraneural myeloid body cells (SMB cells) in the quiescent and LPS-activated state, while plays an inhibitory role in the proliferation of quiescent and activated leukocytes in lampreys. Furthermore, caspase-3/7 activity analysis indicates that the lamprey TGF-β2 protects SMB cells from apoptosis after serum deprivation, in contrast to promoting apoptosis of leukocytes. Our composite results offer valuable clues to the origin and evolution of the TGF-β subfamily and imply that TGF-βs are among the most ancestral immune regulators in vertebrates.