Synthesis And Pharmacological Activity Research Of 1α,2α,3α-Trihydroxyurs-12-en-28-oic Acids And Itsderivatives

Objective:To design and synthetize1α,2α,3α–trihydroxyurs-12-en-28-oicacids and itsderivatives and explore its cytotoxicity、antibacterial activity and the protection of its against hydrogen peroxide（H₂O₂）injury of PC12 cells activity,and discuss its primary structure-activity relationship to discovery the drug candidate for further research.Methods:Starting from Ursolic acid（UA）,the A ringwas synthetized by 8-step successive reactions including C-28 benzylation,C-3 methyl sulfonylation,olefination,etc.for hydroxylstructural modification.The structure of the compounds were analyzedby modern spectroscopic techniques(¹H-NMR、¹³C-NMR),Mass spectrometry（ESI）together with physical and chemical methods.The target compoundand the part of itsderivatives of cytotoxicityand against hydrogen peroxide（H₂O₂）injury of PC12 cells were measuredby using the method of MTT.and its antibacterial activity were measured by using ninety-six well microtiter plate.Results:Nineteen ursolic acid derivatives were synthesized including 1α,2α,3α–trihydroxyurs-12-en-28-oic acids,seven trihydroxyurs-12-en-28-oic acids chemical intermediate and eleven 1α,2α,3α-trihydroxyurs-12-en-28-oic acids derivatives.The cytotoxicity of conpound（Ua-8）and the target compound（Ua-10）was lower than that of UA.The derivative compounds U10-3、U10-5、U10-6 had hardly anycytotoxicity.The derivative compounds Ua-9（Benzyl）、U10-1（Ethyl bromide）、U10-2（Hydroxy ethane）、U10-4（N-methyl piperazine）had great cytotoxicity.UA had no protective effect on hydrogen peroxide（H₂O₂）damage in PC12 cells.Ua-8 Ua-10 had certain resistance tohydrogen peroxide injury protect PC12 cell activity,and after the c-28 introduced carbon fatty is introduced,and then the diethylamino,diethanol amine,tryptamine（U10-3,U10-5,U10-6）significantly enhanced resistance to hydrogen peroxide injury of PC12 cell activity,including the introduction of diethanolamine,tryptaminebased resistance to hydrogen peroxide injury of PC12 cell activity was strong in positive control of vitamin E.The derivative compounds against Escherichiacoli were weaker than ursolic acid（UA）,and the inhibition of Staphylococcus aureus and Bacillussubtilis wasbetter,especially Ua-9（Benzyl）,U10-2（hydroxyethane）,U10-3（diethylamino）,U10-4（N-methyl piperazine）.Conclusion:（1）The cytotoxicity and antibacterial activity was reduced and the protection of hydrogen peroxide（H₂O₂）injury of PC12 cells activity was enhanced when the A ring was substituted by tri-oxygen.（2）when the C₂₈ was substituted by Benzyl、hydroxyethane、diethylamino、N-methyl piperazine can significantly enhanced the cytotoxicity,except U10-2（hydroxyl oxide）have theprotection of hydrogen peroxide（H₂O₂）injury of PC12 cells activity which the concentration was 1.0×10^-4mol/L.（3）The cytotoxicity was significantly reduced and the protection of hydrogen peroxide（H₂O₂）injury of PC12 cells activity was obviously enhanced when the C₂₈ was substituted by diethylamine、Diethanolamine and tryptamine,especially U10-5（diethanolamine）,theprotection of hydrogen peroxide（H₂O₂）injury of PC12 cells activity was superior to the positive control（vitamin E）,U10-3（diethylamine）also haveexcellent antibacterial activity.（4）Compared with UA、Ua-10、U10-3、U10-5,the protection of hydrogen peroxide（H₂O₂）injury of PC12 cells activity increased graduallywith the increased of hydroxyl groups.Insummary,U10-3,U10-5,U10-6 compounds had good activity and had the value of further study.