The skin barrier serves as the body’s primary defense against environmental insults such as ultraviolet (UV) radiation. Exposure to UV light, particularly UVB, is a significant factor contributing to skin barrier damage, leading to conditions like oxidative stress, inflammation, photoaging, and even cancer. UVB irradiation disrupts intracellular Ca2+ homeostasis and stimulates the production of reactive oxygen species (ROS), initiating a vicious cycle that activates inflammatory pathways, such as the NF-κB pathway, and ultimately results in skin inflammation and barrier damage. This damage weakens the skin’s resistance, causing symptoms like water loss, dryness, roughness, stinging, and itching. While Daemonorops draco Bl. extract, also known as Sanguis draconis, has traditional uses in skin health, promoting muscle and wound healing, and is recognized in the Pharmacopoeia of the People’s Republic of China, its specific active components and detailed mechanisms for anti-inflammatory and barrier repair effects have remained largely unclear. This study aimed to identify active monomers from D. draco and investigate their mechanisms in repairing skin barrier damage induced by UVB, providing a scientific basis for its application in dermatology.
Methods
The study involved the extraction and purification of seven active monomers (XJ-1 ~ XJ-7) from D. draco using various chromatographic methods. A cellular model of UVB-induced skin damage was established by irradiating HaCaT keratinocytes with an optimal dose of 0.15 J/cm², which significantly increased inflammatory markers without causing excessive cell death. The effects of the extracted monomers on inflammatory markers like IL-1β, TNF-α, and PGE-2 were initially assessed using ELISA to identify the most promising compound. Further in-depth mechanistic studies focused on the best-screened monomer, XJ-2, employing techniques such as fluorescent probes and flow cytometry to measure ROS and Ca2+ levels, and Western blotting, immunofluorescence, and PCR to examine the expression of key proteins in the NF-κB pathway (IKKα, NF-κB p65, inflammatory cytokines) and skin barrier function (FLG, AQP-3, CLDN1).
Key Findings
• Seven active compounds (XJ-1 ~ XJ-7) were successfully extracted and purified from D. draco.
• UVB irradiation at 0.15 J/cm² significantly induced inflammation in HaCaT cells, characterized by increased levels of TNF-α and IL-1β.
• All seven compounds (XJ-1 ~ XJ-7) reduced the expression of inflammatory factors, but XJ-2 demonstrated the most significant inhibitory effect on IL-1β, TNF-α, and PGE-2 expression in UVB-induced HaCaT cells.
• XJ-2 treatment significantly inhibited the increase in intracellular ROS production induced by UVB irradiation in HaCaT cells in a dose-dependent manner.
• XJ-2 significantly reduced intracellular Ca2+ levels and decreased the expression of TRPV4 protein in UVB-damaged HaCaT cells, effectively protecting cellular function and preventing damage caused by Ca2+ influx.
• XJ-2 effectively reduced UVB-induced inflammatory damage by regulating the NF-κB signaling pathway; it significantly inhibited the expression of IKKα/NF-κB protein and the translocation of NF-κB p65 subunit to the nucleus, leading to downregulation of pro-inflammatory cytokines like IL-1β and TNF-α.
• XJ-2 significantly increased the expression levels of skin barrier-related proteins, including FLG, AQP-3, and CLDN1, in HaCaT cells after UVB injury, indicating its ability to promote the repair of the damaged skin barrier, maintain tight junctions, and support skin hydration.
• The study proposes that XJ-2’s effects involve inhibiting oxidative stress and Ca2+ influx, regulating the NF-κB/IKKα pathway to alleviate inflammation, and enhancing the expression of repair and moisturizing factors.
This research identifies (2S)-5-methoxy-6-methylflavan-7-ol (XJ-2) as a potent active component extracted from Daemonorops draco Bl., exhibiting excellent anti-inflammatory and barrier repair properties in a UVB-induced skin damage model using HaCaT cells. The key novelty lies in isolating this specific monomer and elucidating its intricate mechanism of action, which involves simultaneously inhibiting oxidative stress by reducing ROS production, regulating intracellular calcium homeostasis by targeting TRPV4, suppressing the NF-κB inflammatory pathway, and promoting the expression of essential skin barrier proteins (FLG, AQP-3, CLDN1). These findings provide a scientific foundation for understanding D. draco‘s dermatological benefits. The study suggests that XJ-2 holds great potential for the development of dermatological therapeutic drugs and skincare products, particularly for treating inflammatory skin diseases like atopic dermatitis and psoriasis. However, the authors emphasize that this study was conducted at the cellular level, and further investigations using animal models or 3D skin models are required to verify the skin barrier repair effects and safety of XJ-2 in vivo. Future work should also aim to identify precise molecular targets and signaling pathways and potentially optimize the compound’s structure.
Link to the study: https://www.nature.com/articles/s41598-025-01289-4
