新型NO-H2S供体型开环丁苯酞衍生物的设计、合成及抗脑缺血活性研究

Ischemic stroke is a high-risk disease, which pathogenesis is very complex. However, there is still a scarcity of effective drug with satisfactory safety worldwide. 3-n-Butylphthalide (NBP) is an anti-ischemic stroke drug with independent intellectual property rights in China. NBP can inhibit platelet aggregation, anti-thrombosis, decrease brain infarct volume and so on, but its effect is not entirely satisfactory. In view of that increasing exogenous nitric oxide (NO) could relax blood vessels, inhibit platelet aggregation and protect the neuronal cells in the early phase of ischemic stroke. Meanwhile, hydrogen sulfide (H2S) plays an positive role in many aspects in cerebral ischemia reperfusion injury, such as, relaxing blood vessels, scavenging free radicals, anti-oxidative stress and so on. Therefore, we believed that derivatives of ring-opened NBP, which could adjust both NO and H2S level, should be a new strategy of prevention and treatment of ischemic stroke. Based on the above research, we took (S)-HPBA, a ring-opening derivative of (S)-NBP, as the lead compound, designed and synthesized series of novel NO-H2S releasing derivatives of ring-opened NBP. Their anti-ischemic stroke activities, NO- and H2S -releasing assay, stability study and aqueous solubility test will be evaluated, and the mechanism and pharmacokinetics of these active derivatives will be studied. With the best expectation that a promising anti-ischemic stroke candidate compound with better efficacy and aqueous solubility than (S)-NBP will be discovered by our effort, and lay a foundation for the development of new drugs with high-potency for treatment of ischemic stroke.

脑缺血是一种发病机制非常复杂的高危疾病，目前国内外尚无理想的防治药物。丁苯酞（NBP）是具有我国自主知识产权的抗脑缺血药物，具有抗血小板聚集、抗血栓、减缓脑梗死等多种生物活性，但其总体疗效不高。考虑到在脑缺血发病早期增加外源性一氧化氮（NO）可舒张血管、抑制血小板聚集、保护神经元细胞等；还考虑到硫化氢（H2S）在脑缺血-再灌注中可发挥舒张血管、清除自由基、抗氧化应激等积极作用。我们认为研究同时调节NO和 H2S水平的NBP衍生物可能是一种防治脑缺血的新策略。鉴于此，本项目以抗脑缺血活性较突出的(S)-NBP开环化合物(S)-HPBA为先导物，设计、合成新型NO-H2S供体型开环NBP衍生物，并对其进行抗脑缺血活性研究、NO和 H2S释放测定、水溶性及稳定性研究、药代动力学及作用机制研究，期望获得在疗效和水溶性方面比(S)-NBP更具优势的候选化合物，为开发新型高效的治疗脑缺血药物奠定基础。

脑缺血是一种发病机制非常复杂的高危疾病，目前国内外尚无理想的防治药物。丁苯酞（NBP）是具有我国自主知识产权的抗脑缺血药物，具有抗血小板聚集、抗血栓、减缓脑梗死等多种生物活性，但其总体疗效不高。考虑到一氧化氮（NO）和硫化氢（H2S）在脑缺血中的积极作用，我们认为研究调节NO和H2S水平的NBP衍生物可能是一种防治脑缺血的新策略。首先，本项目以抗脑缺血活性较突出的(S)-NBP的开环化合物为先导物，设计合成了一类新型NBP衍生物（NOSH-NBP-1-6），并对其抗血小板聚集活性进行了相应研究。结果表明，NOSH-NBP-1-6的血小板聚集活性均优于(S)-NBP，其中，NOSH-NBP-5具有较(S)-NBP、NO-(S)-NBP片段和H2S-(S)-NBP片段更好的抗血小板聚集活性，提示NOSH-NBP-5的各个结构片段可能是通过协同作用，发挥比(S)-NBP更强的体外抗血小板聚集活性。此外，NOSH-NBP-5的体外NO和H2S释放量略高于活性较低的其它化合物，提示适量浓度的NO和H2S释放有利于提高化合物血小板聚集抑制活性。脑匀浆原药释放实验显示，NOSH-NBP-5可在脑匀浆中释放出原药(S)-NBP。接下来，本项目以具有抗氧化、抗血小板作用的阿魏酸为连接基团，将NBP开环衍生物与硝酸酯类NO供体和H2S供体杂合，设计合成了一类新型化合物8a-8o，并对其进行了抗脑缺血活性研究。研究表明，8d体外具有较NBP、NO-NBP片段和H2S-NBP片段更好的抗血小板聚集活性。此外，8d在体外可释放出适量的NO和H2S，而适量浓度的NO和H2S释放有利于改善心血管疾病和促进脑血液循环。体内抗脑缺血试验发现，缺血再灌注大鼠口服8d能更显著性地减轻神经行为功能损伤，减少脑梗死面积及脑含水量，提高脑内抗氧化剂的水平降低脑内氧化剂的水平，从而保护脑神经元。最后，本项目设计合成了一类硫化氢供体型NBP开环衍生物5a-5f，并对其进行了抗血小板聚集活性研究。结果表明，5a-5f的血小板抑制活性比NBP均有显著提高。其中，5e的活性提高最为明显，化合物5e的其他药理活性正在进行中。综上所述，我们筛选出3个可作为潜在的抗血小板抑制剂NOSH-NBP-5、8d和5e，具有深入研究的价值。