新的核苷类化合物β-L-D4A的化学合成及体外抗HBV作用

目的以D型谷氨酸为原料，通过一系列化学转化，合成了新的核苷类化合物β-L-D4A，并初步探索其体外抗HBV作用。方法合成β-L-D4A，用红外光谱、核磁共振氢谱和质谱确证目标化合物的结构，以2.2.15细胞(HepG2细胞进行HBV基因组转染后所得)培养为基础，Southern印迹法检测不同浓度化合物体外抑制HNV DNA复制作用，并求出50%抑制的药物浓度，即EC₅₀。以四噻唑蓝(MTT)比色分析法检测不同浓度药物的细胞毒性，求出IC₅₀。结果化合物β-L-D4A经红外光谱、核磁共振氢谱和质谱确证；2.2.15细胞培养上清液病毒DNA的Southern印迹、自显影结果显示病毒的抑制呈明显的浓度依赖性，计算出EC₅₀为0.2 μmol·L^-1，胞内DNA的Southern印迹、自显影显示类似的结果；细胞毒性实验显示IC₅₀为200 μmol·L^-1。结论体外实验显示β-L-D4A具有明显的抑制病毒DNA复制作用，且无明显的细胞毒性，TI值为1 000，高于临床用Lamivudine (750)，有望开发为临床抗HBV用药。

Synthesis of a novel L-nucleoside , β-L-D4A and its inhibition on the replication of hepatitis B virus in vitro

AIM: Nucleoside analogues have become the most promising candidates of anti-HBV drugs. In this study, beta-L-D4A was synthesized and explored its inhibitiory action against hepatitis B virus (HBV) in 2. 2. 15 cells derived from HepG2 cells transfected with HBV genome. METHODS: beta-L-D4A was stereo-controlled synthesized from D-glutamic acid, and the structure was identified by IR, 1H NMR and MS. 2. 2. 15 Cells were placed at a density of 5 x 10(4) per well in 12-well tissue culture plates, and treated with various concentrations of beta-L-D4A for 6 days. At the end, medium was processed to obtain virions by a polyethlene glycol precipitation method. At the same time, intracellular DNA was also extracted and digested with Hind III. Both of the above DNA were subjected to Southern blot, hybridized with a 32P-labeled HBV probe and autoradiographed. The intensity of the autoradiographic bands was quantitated by densitometric scans of computer and EC50 was calculated. 2. 2. 15 cells were also seeded in 24-well tissue culture plates, and cytotoxicity with different concentrations was examined by MTT method. IC50 was calculated. RESULTS: The synthesized compound structure conformed with beta-L-D4A; Autoradiographic bands showed similar for supernatant and intracellular HBV DNA. Episomal HBV DNA was inhibited in a dose-dependent manner. EC50 0.2 micromol x L(-1). The experiment of cytotoxicity gained IC50 200 micromol x L(-10. CONCLUSION: beta-L-D4A has been synthesized successfully. beta-L-D4A possessed potent inhibitory effect on replication of HBV in vitro with low cytotoxicity, TI value was 1 000. It is expected to be developed clinically into a new anti-HBV drug.