Study On Design, Synthesis And Activities Of (Hetro) Cyclopentane-(Thio) Ketone For Anti-cerebral Ischemic Agents

Cerebral ischemic stroke is a central nervous system disease triggered by several factors. It involvesin many complex pathological mechanisms, including excitatory toxicity of glutamate, release of a large number of free radicals, the inflammatory response, neuronal necrosis and apoptosis. They reinforce each other and promote each other, leading to the severe damage of central nervous system, or even resulting in death. The disease is characterized by the high morbidity, mortality and relapse. However, there are no ideal drugs for the treatment all over the world at present. Therefore, it is very important to seek new drugs with high efficacy, low toxicity and good prognosis for the treatment of cerebral ischemic stroke.In recent years, the problems of the drugs have been increasingly prominent, such as mono-effect, poor safety, narrow therapeutic window and ambigious clinical effects. Thus, based on the idea of ‘a drug for multi-target’, researchers are now seeking novel drugs that can control many factors in the pathological mechanisms in order to treat ischemic stroke by multi-pathway simultaneously.Hydrogen sulfide(H2S) is the third gaseous signal molecule in vivo. Our previous study found that slowly releasing H2 S donor ADT-OH possessed anti-inflammation, protection HT-22 cells damage induced by glutamate and reducing infarct volume. Its analog ADT protected the damaged blood brain barrier and showed longer duration of action in rats by inhibiting the damage of free radicals and neuroinflammation. Ligustraszine, which has diverse neuroprotective effects such as anti-inflammation, anti-free radical damage, anti-apoptotic and thrombolysis, is one of the common drugs to treat cerebral ischemic stroke. Resveratrol enhances scavenging free radical, reduces platelet aggregation and possesses anti-inflammation. Nec-1 protected ischemic stroke-induced damaged neurons by significantly reducing ischemic infarct volume and inhibiting the response of inflammation. These four compounds all have characteristics of ‘a drug for multi-target’ against cerebral ischemia stroke.According to the idea of ‘a drug for multi-target’, there were 58 compounds(four classes), among which 24 compounds are novel, were designed and synthesized. They all contained(hetro) cyclopentane-(thio) ketone and were confirmed by 1H-NMR, 13C-NMR and HR-MS.Ninteen compounds(SH-I1-19) were syntheiszed by modification of the aromatic ring of ADT-OH, and there are 6 new structures(compound SH-I4,15,16,17,18,19). Their neuroprotective effects have been evaluated on HT-22 hippocampal neuron cells damaged by glutamatethrough MTT method. The pharmacological results demonstrated that most of the compounds SH-I had potent neuroprotection. Ninecompounds(SH-I1-3,5-9,13) significantly improved the survival rate of the damaged cellsat all the tested concentration of 0.1~100μM(P<0.01), and five compounds(SH-I4, 10, 11, 14, 16) at concentration of 10~100μM(P<0.05, P<0.01).Based the study that NMDA receptor antagonist memantine reduced the neurotoxicity of H2 S at high concentration, nine novel structures(SH-II1-9) were designed by coupling ADT-OH with memantine through alkanes as linkers, and were synthesized by four step reactions from ADT-OH. Their neuroprotection against glutamate induced damage on HT-22 cells was evaluated by MTT method. The results indicatedthat these compounds markedly increased the survival rates of damaged HT-22 cells only at the concentration of 1μM(P<0.01).Based on the structure of resveratrol and Nec-1, 22 compounds were designed and synthesized, among which SH-III15 is novel. Their affecting on the LDH releasing rate of HT-22 cells was evaluated through released LDH assay. The results demonstrated that 7 compounds(SH-III2,5,9,10,12,16,18) not only had no toxicity to normal cells at all the tested concentrations(0.1 to 100μM), but also protected OGD-injured HT-22 cells at some concentrations. In particular, SH-III5,10 significantly decreased LDH values of ODG-injured HT-22 cells at the concentration ranging from 0.1 to 50μM(P<0.05, P<0.01).Eight novel SH-IV compounds were designed by coupling ligustraszine with five-member-hetrocycle. They were prepared by 6 step reactions from ligustrazine hydrochloride, and the synthesis methods of intermediate i, m were explored.Compound SH-IV1,3,5,6 were assayed their activities on HT-22 cells by MTT method. The results showed that compound SH-IV1,3,5,6 had no toxicity to normal HT-22 cells at all the tested concentrations ranging from 0.1 to 100μM. Compound SH-IV5, 6 significantly improved the survival rates of OGD-damaged HT-22 cells at the concentration of 0.1, 1, 10μM(P<0.05, P<0.01). Compound SH-IV1 at the concentration of 0.1μM showed good neuroprotection against OGD-induced damaged neuron cells, while it showed no protection and no toxicity at the other concentrations(1~100μM).In conclusion, most of the target compounds possessed neuroprotection, especially compounds SH-I1-3, 5-9, 13, SH-III5,10 and SH-IV5, 6. Some compounds are being go further pharmacologicalstudy.