Development Of Novel Pentanediamide As S-adenosyl-L-homocysteine Hydrolase Inhibitors

Objective:S-adenosyl-L-homocysteine hydrolase（SAHase）is a widely present and highly conserved enzyme that catalyzes the reversible hydrolysis of S-adenosyl-L-homocysteine（SAH）to homocysteine（Hcy）and adenosine（Ado）.SAH is the product of all S-adenosyl methionine（SAM）-dependent transmethylation reactions,and SAHase plays a crucial role in the regulation of SAM-mediated methylation reactions.SAHase inhibitors have shown a variety of pharmacological activities,including antitumor,antiviral,antibacterial,antiparasitic,and anti-inflammatory activities.In this study,we designed and synthesized a series of novel pentanediamide derivatives using the previously discovered aromatic amide derivatives as lead compound,and evaluated for their antitumor,antiviral,antibacterial and SAHase inhibitory activities in vitro.In addition,the molecular simulation was further studied,and the preliminary structure-activity relationship was also discussed in this study.Methods:A total of 21 novel pentanediamide derivatives were synthesized by condensation and amidation reactions using substituted phenylglutaric acid as the raw material.The inhibition of SAHase activity of all synthesized compounds was tested in vitro at 25μM and 5μM using fluorometric assay.All synthesized compounds were examined for cytotoxic activity against four tumor cell lines used the MTT method,including human breast cancer cells（MCF-7）,human gastric cancer cells（MGC-803）,human lung cancer cells（A549）and human cervical cancer cells（Hela）.The antibacterial activity of all synthesized compounds was tested against four strains Staphylococcus aureus（S.aureus）ATCC25923,Enterococcus faecalis（E.coli）ATCC25922,Bacillus subtilis（B.subtilis）ATCC6633 and Pseudomonas aeruginosa（P.aeruginosa）ATCC27853 in vitro.Two virus strains,respiratory syncytial virus（RSV）and vesicular stomatitis virus（VSV）,were selected to tested for the antiviral activity of the optimal compounds（9i,9p and 9r）in vitro.Results and Conclusions:In this paper,21 novel compounds were designed and synthesized,and all the synthesized compounds were confirmed by ¹H NMR,¹³C NMR and ESI-MS.All synthesized compounds exhibited inhibition of SAHase activity at 25μM and 5μM.9 compounds（9a,9b,9c,9d,9i,9p,9r,9s,9u）displayed high level of inhibition rate with more than 90%at 25μM,especially,5 compounds（9b,9d,9i,9p,9s）exhibited more potent than the that of the positive control 3-deazaadenosine.Interestingly,6 compounds（9a,9b,9i,9p,9r,9s）showed more high inhibition level of inhibition rate than 3-deazaadenosine at 5μM.Some target compounds showed significant antitumor activity,especially,6 compounds（9a,9i,9j,9p,9q,9r）displayed strong inhibitory activity against MCF-7 and A549,which is more effective than that of the positive control 5-fluorouracil,specially,compound 9i showed strong inhibitory activity against MCF-7,MGC-803,A549,and Hela with IC₅₀value ranging from 23.16±1.44 to 33.29±2.97μM,which is more potent than that of5-fluorouracil;4 compounds（9b,9c,9f,9j）showed weak inhibitory activity against S.aureus their with MIC values>32μg/m L,and 5 compounds（9a,9c,9f,9g,9j）showed weak inhibitory activity against B.subtilis with their MIC values>32μg/m L.The optimal compound 9i had an EC₅₀ value of 44.8μM and a therapeutic index of 3.015 for RSV,compound 9p had an EC₅₀ value of91.08μM and a therapeutic index of 1.007 for RSV,and compound 9p had an EC₅₀ value of 38.91μM and a therapeutic index of 2.358 for VSV.Some of the synthesized compounds have good ADMET properties and drug-likeness properties.The molecular docking further showed that the optimal compounds（9i,9p and 9r）have strong interactions with SAHase.In summary,21 novel pentanediamide derivatives were designed and synthesized in this study.some compounds showed good SAHase inhibitory activity in vitro;some compounds had significant antitumor activity;However,only some compounds displayed weak antibacterial activity against S.aureus and B.subtilis;The optimal compounds exhibited moderate potency against RSV and VSV.Furthermore,the molecular docking study suggested that some synthesized compounds had good ADMET properties and drug-likeness properties,and the optimal compounds had strong bound to the active site of SAHase,established a SAHase pharmacophore model based on receptor-ligand complex,which can be used for subsequent screening of SAHase inhibitors.All the results could be a guide for developing novel non-adenosine SAHase inhibitors.