脱镁叶绿酸介导白藜芦醇二聚体的合成及其抗自由基和镇痛增强作用

Synthesis of Resveratrol Dimer Induced by Pheophorbide and Its Enhancing Effects on Free Radical Elimination and Analgesic Activity

[目的]探索白藜芦醇低聚物在光敏剂介导下的合成新方法,进一步分析其自由基清除能力和镇痛效应的变化。[方法]将白藜芦醇分散在p H7.4的磷酸缓冲液中,加入脱镁叶绿酸,以630 nm激光照射,过滤除去脱镁叶绿酸,利用高效液相色谱-质谱联用分析滤液中白藜芦醇的聚合产物;采用制备液相色谱法分离白藜芦醇聚合物,用DPPH法和ABTS法进行体外抗自由基活性的测定,通过小鼠热板法和醋酸扭体法考察其镇痛作用。[结果]激光照射后反应液有新色谱峰生成,20 min达到稳态。该峰为白藜芦醇二聚体,转化率为35%。其对50%DPPH和ABTS自由基的清除时浓度分别为230μg·m L-1和273μg·m L-1,热板法痛阈达峰时间分别为180 min,醋酸扭体抑制率62.6%,显著优于白藜芦醇。[结论]白藜芦醇在脱镁叶绿酸受红光激发后聚合生成了二聚体,白藜芦醇和其二聚体均有清除自由基效果和镇痛活性,且二聚体作用能力更强。

[Objective] To explore a new method of synthesis of resveratrol oligmer induced by photosensitizers, further analyze its free radical scavenging activity and analgesic activity. [Method] Resveratrol was dispersed in p H 7.4 phosphate buffer solution, mixed with pheophorbide, then illuminated by laser at 630 nm. The oligmers in the filtrate were analyzed by HPLC-MS and isolated by preparative liquid chromatography. Free radical scavenging activity was determined by DPPH and ABTS method, and the analgesic effect was measured by hot plate test and acetic acid writhing test in mice.[Result] A new peak occurred and reached stable in reactive solution after 20 min illumination. It was identified as the dimer of resveratrol with conversion of 35%. Its concentrations on inhibition of 50% DPPH and ABTS radical were respectively 230 μg·m L-1and 273 μg·m L-1. It reached maximum pain threshold at 180 min, and the inhibition rate of writhing number was 62.6% with better effects than resveratrol. [Conclusion] Reseratrol can be polymerized to the dimer after pheophorbide excited by red light, the resveratrol and its dimer both have the ability of eliminating free radicals and analgesic effects, but the dimer has the stronger activity.