Solid Phase Synthesis Of Cyclic Pentapeptide And Evaluation Of Bioactivity

Tumor has become one of the major diseases that affect human life and health.The number of patients who die from cancer diseases each year has exceeded cardiovascular and cerebrovascular diseases.Therefore,research on anti-tumor drugs has received more and more attention.Cyclic peptides have a good activity in inhibiting tumor growth and are potential antitumor drugs.Sansalvamide A is a cyclic peptide ester isolated from a marine fungus named Fusarium.It has been found through research that it has good anti-cancer and other physiological activities.Therefore,its design,synthesis and activity evaluation of its total synthesis and related analogues have been performed.It has become a hot spot in the field of cyclic peptide chemistry.In this study,a new analogue of Sansalvamide A was designed,N-methyl-L-leucine,naphthylalanine,and aspartic acid were introduced,and the related cyclic peptide was synthesized by solid-phase synthesis using a chlorine resin as a carrier.On this basis,synthetic compounds were evaluated for their anti-tumor activity at the cellular level.Completed Fmoc-N-Me-L-Leu,Fmoc-L-naphthylalanine,Fmoc-L-Asp-β-OBzl,Fmoc-L-Asp-β-Ot Bu The synthesis of six amino acids,butyl ester,Fmoc-L-leucine and Fmoc-L-proline,lays the foundation for solid-phase synthesis.The solid phase preparation method and conditions for the chain peptide were selected and optimized,and the strategy for lengthening the peptide chain was screened.A one-by-one connection method was adopted,2-chlorotrityl chloride resin was used as a carrier,HATU/HOAt was selected as a condensing agent,25%piperidine/DMF solution was used as a deprotection reagent,HFIP/DCM solution was used as a cutting reagent,and microwave solid phase was used.The target peptides were synthesized by a synthesizer and recrystallized and purified.Polypeptides were purified and 1H NMR and HRMS were used to characterize the intermediate products.The cyclization of the peptide peptides is accomplished in the liquid phase,including the optimization of the condensing agent,the reaction temperature,and the reaction solvent.Using anhydrous dichloromethane,tetrahydrofuran and N,N-dimethylformamide as solvents,and HATU/HBTU and Py BOP as condensing agents,the yield of cyclic peptides can be increased from 20%to 35%.The separation and purification of the cyclic peptides was carried out by recrystallization and column chromatography.The structure of the target product was characterized by¹H NMR,¹³C NMR and HRMS.Human malignant melanoma A375 cells,renal clear cell adenocarcinoma 786-O cells,osteosarcoma MNNG-HOSCl#5 cells,and gastric cancer 7901 cell were selected as biological models for activity evaluation.The results showed that the inhibitory rate of compound X-5 on human osteosarcoma MNNG-HOSCl#5 cells reached 63.71%;the inhibitory rate of compound LRJ-1 on these four tumor cells was up to 70%,and the inhibitory effect of LRJ-2 was slight.Weaker.Both compounds LRJ-3 and LRJ-4 had inhibitory effects on four cancer cells and showed moderate biological activity.