Synthesis And Optimization Of Caffeic Acid M-nitro Phenethyl Ester And Its Effects On Atherosclerosis

Caffeic acid phenethyl ester（CAPE）is one of the main active components of propolis.The bioactivities of anti-inflammatory,anti-oxidant and anti-tumor of propolis are related to the CAPE contained.According to the structure of CAPE,its o-diphenol hydroxyl（catechol）structure has good ability of electron and hydrogen supply,and its trans double bond is more active.It has good lipophilicity,which is helpful to penetrate the biomembrane and has obvious decisive effect on its biological activity.Derivatives and analogues for this structure have been designed to obtain new molecules with higher activity.In this research,the synthesis and anti-atherosclerotic effect of nitro substituted derivatives on phenylethanol ring of CAPE were studied.Synthesis design and process optimization:comparing the physicochemical parameters,lipid water partition coefficient,total molecular energy and organ toxicity of nitro derivatives of CAPE,using design software such as Chemoffice and SYBYL-X,the caffeic acid m-nitro phenyl ethyl ester（CAPE-mNO₂）with higher activity and less side effects was designed and synthesized based on the study of nitro derivatives such as caffeic acid p-nitro phenylethyl ester.The intermediate,m-nitrophenylethanol,was synthesized by esterification and reduction reaction of m-nitrophenylacetic acid.Then,the target compound CAPE-mNO₂ was synthesized by acyl-chlorination and esterification of caffeic acid and m-nitrophenylethanol.The structure of the intermediates and products was characterized by melting point measurement,NMR carbon spectrum,hydrogen spectrum and mass spectrum.The effects of intermediate reduction system,molar ratio of raw materials,reaction solvent and reaction temperature on the yield of the product were investigated.The optimum synthesis conditions were as follows:the yield of intermediate was 58%when NaBH₄/THF was used as reduction system;the yield of the target product was 69.3%when the molar ratio of caffeic acid to m-nitrophenylethanol was 1.0:1.5,nitromethane was used as reaction solvent,acylation temperature was 80℃and esterification temperature was 110℃.Studies on anti-atherosclerosis effect:the Sprague Dawley（SD）rats were used to establish atherosclerosis model by high fat and cholesterol diet and intraperitoneal injection of Vitamin D₃.The experiment was divided into five groups:control group,model control group,CAPE group（1.0mg/kg/day）,High-mNO₂ group（1.0mg/kg/day）and Low-mNO₂ group（0.7mg/kg/day）.The results showed that the designed and synthesized CAPE-mNO₂ could reduce the level of TG,TC and LDL-C,as well as increase HDL-C level in serum of atherosclerotic rats.Results of immunohistochemistry showed that CAPE-mNO₂ decreased the expression of collagen I andα-SMA in aortic tissues.Western blot analysis showed that CAPE-mNO₂decreased TNF-αand IL-6 expressions and increased the expression of anti-inflammatory factor IL-10 by down regulating NF-κB.CAPE-mNO₂ could also reduce the lipid deposition of aorta by down regulating the expression of TGF-β₁,MMP9,Vimentin and CTGF,and inhibit the fibrosis of aortae and lung in atherosclerotic rats.Besides,it could up regulate PPAR-αand IL-10 expression and down regulate the expression of Vimentin to improve liver fibrosis.