Abstract：
Long-term exposure to ultraviolet radiation may cause photoaging of skin tissues. Coreopsis tinctoria Nutt. riches a variety of flavonoids with strong antioxidant activities. In the present study, the main antioxidant flavonoid was isolated from C. tinctoria and identified as okanin by Mass spectrum and Nuclear Magnetic Resonance Spectroscopy. Okanin was found to effectively reduce the malondialdehyde content, increase various intracellular antioxidant enzyme activities, relieve epidermal hyperplasia and dermal damage caused by UVB irradiation, and increase the collagen fibers\' content in the dorsal skin tissue of mice. Immunohistochemical analysis showed that okanin effectively counteracted the photoaging effect of UVB-induced by down-regulating IL-1, IL-6, TNF-α, and COX-2, and up-regulating COL-1, COL-3, and HYP expression. In addition, okanin can inhibit skin photoaging by regulating TNF-β/Smad2-3, MAPK, P13K/AKT, and NF-κB signaling pathways. In particular, the three key markers of photoaging, MMP (MMP-1/-3/-9), were down-regulated and five collagen synthesis genes (COL1A1, COL3A1, COL5A2, COL6A1, and COL7A1) were up-regulated, underlines the direct anti-photoaging mechanism of okanin in preventing collagen degradation and promoting collagen synthesis. The current investigation provides new insights into the great potential of okanin in alleviating skin photoaging and lays theoretical references for the development ofanti-photoaging products.
摘要：
长期暴露于紫外线辐射可能导致皮肤组织的光老化。金鸡菊tinctoriaNutt.丰富多种具有较强抗氧化活性的黄酮类化合物。在本研究中,主要的抗氧化剂类黄酮是从丁香中分离得到的，通过质谱和核磁共振波谱鉴定为okanin。发现Okanin可以有效降低丙二醛含量，增加各种细胞内抗氧化酶的活性，减轻UVB照射引起的表皮增生和真皮损伤，并增加小鼠背部皮肤组织中胶原纤维的含量。免疫组织化学分析显示,okanin可通过下调IL-1、IL-6、TNF-α、和COX-2，并上调COL-1，COL-3和HYP的表达。此外,okanin通过调节TNF-β/Smad2-3、MAPK,抑制皮肤光老化,P13K/AKT,和NF-κB信号通路。特别是,光老化的三个关键标志，MMP（MMP-1/-3/-9），下调，五个胶原蛋白合成基因（COL1A1，COL3A1，COL5A2，COL6A1和COL7A1）上调，强调了奥卡宁在防止胶原蛋白降解和促进胶原蛋白合成方面的直接抗光老化机制。当前的研究为奥卡宁在缓解皮肤光老化方面的巨大潜力提供了新的见解，并为开发抗光老化产品提供了理论参考。
