Synthesis And Biological Activity Studies Of Endomorphin And [Dmt~1]DALDA Analogs

Dmt-Pro-1-Nal-NH2 and Dmt-Pro-Tmp-Tmp-NH2 have ? receptor agonist and ?opioid antagonistic activity.The opiate molecules with ? receptor agonist,? opioid antagonistic activity and not activated ? arresting signaling pathway can have some features such as low tolerance,low dependence,low respiratory and low gastrointestinal adverse reactions.In order to study the activity of these two compounds in vivo,we need a lot of synthesis.In the first part of the thesis,we synthesized 1g of these two peptides by liquid phase peptide synthesis method.Preliminary pharmacological studies showed that the analgesic activity of Dmt-Pro-Tmp-Tmp-NH2 was four times that of morphine.[Dmt1]DALDA(Dmt-D-Arg-Phe-Lys-NH2)is a highly potent and extraoridinary selectivity ?-opioid receptor agonist which is a dermophin-derived tetrapeptide.Its ?receptor binding activity is seven times than that of morphine.At the same time,it can penetrate the cell membrane,and has a strong stability of the enzyme.[Dmt1]DALDA can inhibit rat spinal cord synaptosomes uptake of norepinephrine.Also it can promote the release of dynorphin,5-methionine enkephalin.These additional features and their effects on the strong activation of ?opioid receptor make[Dmt1]DALDA have strong analgesic activity.In addition,[Dmt1]DALDA is able to target the mitochondrial inner membrance.It is an antioxidant which has a very good anti chroni pain effect.Although[Dmt1]DALDA is a promising analgesic,there are still some tolerance in the usage of the drug.Previously,we used phenylalanine analogues to substitude phenylalanine in[Dmt1]DALDA and studied the structure activity relationship.Here,we used tyrosine analogues to sunstitude tyrosine in[Dmt1]DALDA in order to form[Dmt1]DALDA analogues.We hope to futher study the structure activity relationship and to improve the ? receptor binding activity,selectivity and antioxidant capacity.The tyrosine analogues are Tmt,Emt,Imt,Det.Pharmacological study display that[Emt1]DALDA and[Tmt1]DALDA display strong ? opioid receptor agonist activity and[Det1]DALDA display moderate intensity of ? opioid receptor agonist activity.In the experiment of anti DPPH radical,We found that[Emt1]DALDA and[Tmt1]DALDA had stronger antioxidant capacity than[Dmt1]DALDA.Therefore,the anti chronic pain effect of these two compounds needs to be further studied.In addition,[Dmt1,Tmp3]EM-2(Dmt-Pro-Tmp-Phe-NH2)has ? receptor agonist and ? opioid antagonistic activity.The opiate molecules with ? receptor agonist,?opioid antagonistic activity and not activated ? arresti signaling pathway can have-some features such as low tolerance,low dependence,low respiratory and low gastrointestinal adverse reactions.But the compound also have some deficiencies:the ability to penetrate the cell membrance,the stability of enzymatic degradation.The enzymatic degradation of EM is mainly from the amide bond breaking of Pro-Phe/Trp.In order to improve[Dmt1,Tmp3]EM-2 enzyme degradation stability and prevent the hydrolysis of dipeptidyl peptidase,We study the structure activity relationship of proline at position 2,From the 4-hydroxy proline,We synthesized cis-4-(trifluoromethyl)-L-proline,cis-4-fluoro-L-proline,cis-4-methyl-L-pro line,4-methylene-L-proline.Using the synthetized proline and 4-hydroxy proline,we further synthetize five tetrapeptides.The introduction of trifluoromethyl,fluoride,methyl can improve the stability of the enzymatic hydrolysis,at the same time,it can enhance the fat soluble,provide the ability to pass the blood brain barrier.Similarly,the proline derivatives was substituted for the 2 psotion of tripeptide Dmt-Pro-l-Nal-NH2.We synthesis the tripeptide of Dmt-(4-CF3)-Pro-1-Nal-NH2,Dmt-(4-CH3)-Pro-1-Nal-NH2,Dmt-Hyp-1-Nal-NH2,Dmt-(4-F)-Pro-1-Nal-NH2,Dmt-(4-(CH2=))-Pro-1-Nal-NH2.Preliminary pharmacological characterization is going on.