Synthesis And Biological Evaluation Of Ferulic Acid Derivatives Coupled To Nitric Oxide Donors In The Treatment Of Kidney Disease

Ferulic acid (FA), commonly found in many Chinese herbal medicines, exists as a phenolicacid which has prominent effect in the treatment of kidney disease by anti-inflammatory,inhibiting platelet aggregation and as an antagonist of endothelin (ET), thromboxane A2(TXA2)and superoxide radicals. NO is a significant biological factor involved in the body regulation. Theeffects of NO on the kidneys contain the improvement of renal hemodynamics, regulation theresistance of renal, inhibition reabsorption of sodium and premotion excretion of urinary sodium.Based on the important roles of both ferulic acid and NO in the treatment of kidney disease, themain work of this thesis is summarized as follows:1. A serises of FA derivatives coupled to different NO donors were designed and synthesized inorder to find out a better one in the treatment of kidney disease.4-nitrate ethoxy (propoxy\butoxy)-3-methoxy cinnamate salt derivatives (compounds12-14) were the final products. Thestructures of all compounds were determined by1H NMR and MS.2. The vitro tests were carried out based on the compound’s structure and pharmacologicalactivity.(1) The vitro NO release capabilities of compounds12-14were determined by Greissmethod in five environments (PBS, cysteine, serum, kidney and liver) respectively. Comparedwith the control group, compounds12-14had the ability to release NO in differentenvironment. In the cysteine environment, the NO release rates of compounds12-14were43.94±2.35%,27.06±1.23%and22.82±0.06%respectively. So in the same environment,their capability was12>13>14. For compound12, the largest NO release rate in the PBS,cysteine, serum, kidney and liver environment were:7.27±0.17%,43.94±2.35%,8.16±0.12%,9.77±0.16%and9.06±0.07%respectively. That means for the same compound, thecapability of NO releasing in the cysteine environment was higher than the other environments.This result was helpful in the further study of the vivo NO releasing capability.(2)Based onthe determination of NO release capability in vitro, further investigation of the compounds onthe the rat aortic rings was carried out. After the rat aortic rings were precontracted by KCl,compounds were added in an accumulated way. Obvious relaxing effects were observed incompounds12-14while the control and sodium ferulate weren’t. When the final concentrationof the compounds12-14were10-3mol/L, the relaxation rates were77.15±2.53%,65.59±0.71%and56.96±1.48%respectively. However, these kinds of relaxation were reduced to72.72±1.52%,49.57±1.51%and46.02±2.07%by adding MB. That means one mechanismof the relaxing effect was the releasing of NO activated guanylate cyclase (GC), thenincreased the level of cyclic GMP and finally made a vasodilation.(3)The inhibition of compounds12-14on ADP-induced platelet aggregation were determined by Bron method.Compared with the control group, compounds12-14had a strong inhibitory effect oninhibiting the ADP-induced platelet aggregation. This result reflected that the combinationmade the inhibition better.(4)The prothrombin time (PT) and activated partial thromboplastintime (APTT) of compounds12-14were determined by blood coagulation analyzer.The resultsshowed that the PT and APTT values were not significantly changed, suggesting thatcompounds12-14showed no anticoagulant activity in the endogenous and exogenouscoagulation system, while they achieved effective anticoagulation mainly through inhibitionof platelet aggregation.3. The interventions of compound6on diabetic mice were studied. The results showed that as aNO donor derivatives of ferulic acid, compound6not only can significantly reduce serumglucose, blood urea nitrogen and creatinine levels, but also has the capability to reduce MDAand hydroxyproline levels and increase kidney SOD and NO levels. Analysis of renalpathology in diabetic mice indicated that compound6can effectively reduced collagendeposition. Therefore, compound6interferes with the pathogenesis of a variety of diabeticnephropathy to protect the renal and decreases glomerulosclerosis and proteinuria to improvethe renal function.