This study evaluated the anti-inflammation and anti-photoaging effects of Camellia sinensis seed flavonoids (CSF) against UVB and UVA irradiation and elucidated the underlying mechanisms. Using UVB-irradiated human keratinocytes and UVA-irradiated human dermal fibroblasts, we found that CSF significantly reduced intracellular ROS and suppressed the secretion of inflammatory factors (PGE-2, TNF-α, IL-6, IL-8) by inhibiting the p38/JNK and NF-κB pathways, along with iNOS and COX-2 expression. In keratinocytes, CSF also downregulated Caspase-3 and upregulated barrier proteins filaggrin and Claudin-1. In fibroblasts, CSF counteracted UVA damage by upregulating collagen IV and XVII at the dermo-epidermal junction and enhancing the production of collagen I, III, and hyaluronic acid in the dermis, mediated via AP-1 inhibition and TGF-β/Smad pathway modulation. These results demonstrate that CSF coordinated anti-inflammatory, barrier-repair, and anti-photoaging actions, highlighting its potential as a promising skincare ingredient.

A fast-paced lifestyle contributes to heightened emotional stress, driving the demand for milder and safer cosmetic ingredients that can counteract stress-induced skin damage—a focus of cutting-edge research in the field. Aim: The aim was to elucidate the role and mechanistic basis of tea (Camellia sinensis) seed meal saponin (Sap) in regulating stress-induced sebum overproduction and inflammatory responses. Methods: The composition and chemical structure of Sap were analyzed using UV-vis absorption spectroscopy, Fourier-transform infrared spectroscopy (FT-IR), and ultra-high-performance liquid chromatography–mass spectrometry (UHPLC-MS). In vitro models of cortisone-induced excessive lipid accumulation and the tumor necrosis factor-alpha (TNF-α)-stimulated inflammatory models were established on sebaceous gland cells (SZ95) and normal human epidermal keratinocytes (NHEKs), respectively. Cortisol and inflammatory cytokine secretion levels in cells were detected using ELISA. Additionally, the signaling pathways were revealed by Western blot (WB) and real-time quantitative polymerase chain reaction (RT-PCR). Results: Five saponins were identified in the Sap extract, all belonging to the oleanolic-acid-type pentacyclic triterpenes. Sap treatment significantly attenuated cortisone-induced cortisol secretion and lipid accumulation in SZ95 sebocytes. Mechanistically, Sap inhibited the 11β-HSD1/SREBP-1 pathway, which mediates its sebosuppressive effects, while concurrently down-regulating the mRNA expression of key downstream transcription factors and enzymes, including SREBP-1, FAS, and ACC. Additionally, Sap treatment significantly attenuated TNF-α-stimulated cortisol secretion and inflammatory cytokine (IL-1β, IL-6, and IL-8) production in NHEK cells through the inhibition of the 11β-HSD1/TLR2/NF-κB signaling pathway. Conclusion: Sap demonstrated dual inhibitory effects, suppressing both emotional-stress-induced sebum overproduction and inflammatory cytokines secretion.

(1) Background: The pursuit of ingredients that possess both anti-melanogenesis and post-inflammatory hyperpigmentation (PIH) prevention effects has become a new research frontier in cosmetics, though there is little work on plant extract-derived ingredients in this direction. (2) Methods: The study involved evaluating the impact of dark tea extract on melanin content and tyrosinase activity in B16 cells. Meanwhile, Ultraviolet B (UVB)-irradiated assays were conducted on HaCaT cells to assess the secretion of inflammatory factors (IL-1α and IL-1β) and paracrine melanogenic factors (α-MSH, bFGF, and ET-1). Additionally, we performed quantitative real-time polymerase chain reaction (RT-PCR) tests to determine whether the signaling pathways of anti-melanogenesis and PIH punctuation are incorrect. (3) Results: The results showed that dark tea extract significantly inhibited melanin content and tyrosinase activity in B16 cells. In HaCaT cells, the extract reduced the secretion of the aforementioned inflammatory and paracrine melanogenic factors, thereby inhibiting PIH. Moreover, the RT-PCR and the Western Blot results indicated that the dark tea extract could inhibit the melanogenesis signaling pathway of α-MSH/MC1R/MITF and their downstream multiple targets of TYRP-1, TYRP-2, and TYR in B16 cells, while it exerted a PIH inhibition effect by downregulating the p38 MAPK/Nrf2/HO-1 signaling pathway. (4) Conclusions: This study suggests that dark tea extract can not only suppress melanogenesis through multiple targets but also can inhibit UVB-induced PIH, hinting at its skin-brightening efficacy as an agent for the restoration of pigmentation disorders.

(-)-Epigallocatechin gallate (EGCG) possesses potent bioactivities but its applications in functional cosmetics is severely limited by its poor water solubility and chemical instability. To overcome these challenges, this study engineered a recombinant levansucrase from Vibrio natriegens to catalyze the transfructosylation of EGCG. The conversion rate of EGCG to fructoside reached 65.59%. The purified product was unequivocally identified as EGCG-1F, with a fructosyl group linked to the 3′-hydroxyl group. Compared to pristine EGCG, EGCG-1F exhibited remarkably enhanced water solubility (96.6-fold that of EGCG) and aqueous stability under acidic and thermal conditions. Biological evaluation revealed that EGCG-1F significantly enhanced HaCaT cell migration, upregulated the expression of basement membrane-associated collagens in ultraviolet B-damaged HaCaT cells, and modulated ultraviolet A-induced senescence in human dermal fibroblasts by type I collagen, type III collagen and matrix metalloproteinase-1 balance. This study demonstrates that enzymatic fructosylation is an effective approach to generate a stable and safe EGCG derivative with potential applications in skin barrier repair and anti-aging functional cosmetics.