Design,synthesis And Activity Of Triptolide Derivatives

Triptolide(TP)is an epoxy diterpenoid lactone which extracted from Tript erygium wilfordii Hook F,with significant anti-inflammatory immunosuppressive activity,it strongly inhibits the expression of pro-inflammatory cytokines such as TNF-?expression levels and block NF-?B signaling pathway,thereby inhibi ting NO synthesis and the expression of nitric oxide synthase(iNOS)to exert anti-inflammatory and immunosuppressive activities;however,TP owns large t oxic,poorly water soluble,and a narrow therapeutic window,these disadvantag es greatly limit its clinical application.The modification of various dosage for ms of pharmaceutics has also failed to solve these problems.This paper adopts precise chemical modification to insert similar groups of NOS-specific substrates into the nucleus of TP:arginine analogues and2-amino-pyridine groups.Two types of TP derivatives were designed and synthesized:amino acid series derivatization(TR-X)and amino-pyridine derivative(TRN-X).In order to reducing the toxicity,this research is going to improve the immunosuppressive targeting and bioavailability of TP which includes the following aspects:1,TR-X series derivatives,using TP as raw material,firstly condensed with succinic anhydride to obtain TP succinate(TR),and under HATU/DIPEA condensation system,TR synthesized the target compound with amino acid without amino-protecting groups by one-pot method.L-Arginine methyl ester derivative(TR-1),yield 92%;L-Arginine derivative(TR-2),yield 94%;N~?-Nitro-L-Arginine methyl ester derivative(TR-3),yield 94%;N~?-Nitro-L-Arginine derivative(TR-4),yield 89%;L-Citrulline derivative(TR-5),yield 93%;L-Lysine derivative(TR-6),yield 91%;L-Lysine methyl ester derivative(TR-7),yield 89%;L-Ornithine derivative(TR-8),yield 94%;L-Ornithine methyl ester derivative(TR-9),yield93%.2,The TRN series of derivatives,in the PyBoP/NMM condensation syst em,TR and 2-aminopyridine compounded in one step condensation to obtain T RN series of derivatives;2-aminopyridine derivatives(TRN-1),yield 76%;4-Methyl-2-Amino-pyridine derivative(TRN-2),yield 83%;4-Ethyl-2-amino-pyrid ine derivative(TRN-3),yield 72%.3.Estabilishing the analytical method of determining the target compound:the HPLC method,and initial testing the stability.And has determined the maximum ultraviolet absorption wavelength of each compound.The TR-X series determined the218 nm as the detection wavelength and TRN series with the detection wavelength of256 nm.Then using the mobile phase to determine the HPLC conditions of TR-X series derivatives with the acetonitrile/methanol-phosphate buffer system,using acetonitrile-water as the mobile phase to detect the TRN series derivatives,more,the HPLC results of the target compounds met the requirements.The stability of the target compounds in the mobile phase was investigated:The TR-X series derivatives remained stable within 72 h;the TRN series derivatives remained stable within 10 d.4,Delayed hypersensitivity model of BALB/C mice sensitized with DNFB.Each target compound was given high dose(5?g/kg),medium dose(1?g/kg),low dose(0.2?g/kg).Three levels of intraperitoneal injection,the positive control was triptolide,the dose level was consistent with the sample,the negative control group was normal saline(dose 10 mL/kg),ear swelling degree was used as an evaluation index,afterwards Anti-inflammatory activity of TR-X series derivatives and TRN series derivatives were measured.The preliminary anti-inflammatory activity test results showed that the anti-inflammatory effects of TR-3,TR-5,TR-8,TR-9 and TRN-3 were better than the corresponding positive controls,and TR-8 had obvious advantages with a dose-effect relationship.Further activity evaluation is in progress.