Fu Haiying, Lin Mingzhang, Muroya Yusa, Hata Kuniki, Katsumura Yosuke, Yokoya Akinari, Shikazono Naoya, Hatano Yoshihiko
Radiation Chemistry and Technology Laboratory, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai, PR China.
Free Radic Res. 2009 Sep;43(9):887-97. doi: 10.1080/10715760903136996.
Silybin (extracted from Silybum marianum) is the major active constituent of silymarin which possesses a wide range of medicinal properties. These properties may be, in part, due to the potent scavenging capacity of oxidizing free radicals. In this context, scavenging radicals (hydroxyl, azide, dibromide anion radicals, nitrite, carbonate, etc.) of silybin have been studied to understand the mechanistic aspects of its action against free radicals. The transients produced in these reactions have been assigned and the rate constants have been measured by pulse radiolysis techniques. Reduction potential determined both by cyclic voltammetry gave a value 0.62+/-0.02 V vs NHE at pH 9. Quantum chemical calculations have been performed to further confirm the different activities of individual hydroxyl groups with the difference of heat of formation. Moreover, silybin also protected plasmid pUC18 DNA from soft X-ray radiation which induced strand breaks. These results are expected to be helpful for a better understanding of the anti-oxidative properties of silybin.
水飞蓟宾（从水飞蓟中提取）是水飞蓟素的主要活性成分，具有广泛的药用特性。这些特性可能部分归因于其对氧化自由基的强大清除能力。在此背景下，对水飞蓟宾清除自由基（羟基、叠氮化物、二溴阴离子自由基、亚硝酸盐、碳酸盐等）进行了研究，以了解其对抗自由基作用的机制。已对这些反应中产生的瞬态进行了归属，并通过脉冲辐解技术测量了速率常数。通过循环伏安法测定的还原电位在pH 9时相对于标准氢电极的值为0.62±0.02 V。已进行量子化学计算以进一步证实各个羟基因生成热的差异而具有不同的活性。此外，水飞蓟宾还保护质粒pUC18 DNA免受诱导链断裂的软X射线辐射。这些结果有望有助于更好地理解水飞蓟宾的抗氧化特性。
