取代芳烃对藻类毒性与结构参数之间的定量关系研究

采用OECD标准方法测定了40种取代芳烃化合物对绿藻的48h急性毒性,毒性最强的是邻二硝基苯,其lg1 EC50为5 04;毒性最弱的是苯酚,其lg1 EC50仅为2 46。计算得到所研究化合物的分子最低空轨道能((ELUMO))、分子最高占有轨道能((EHOMO))、范德华面积((sVdW))及分子量(Mw)。对化合物毒性和结构参数进行了定量的结构与活性关系(QSARs)研究。所研究化合物对绿藻的毒性主要分子的轨道能和空间参数有关。方程(lg1 EC50=-1 029(EHOMO)+0 025(sVdW)-8 322,R2(adj)=0 824)有很好的预测能力,训练组的平均相对误差为6 10%,测试组的平均误差为6 99%。苯酚和苯胺类化合物属于极性麻醉剂,其毒性与空间参数或疏水性有关;硝基苯类是反应型化合物,可作为亲电子试剂,产生相应的潜在毒性更强的亚硝基化合物,其毒性一般与分子轨道能有关。 

Study on Quantitative Relationships for Toxicity and Structure of Substituted Aromatic Hydrocarbons to Algae

The 48 h acute toxicity values of 40 substituted aromatic hydrocarbons to the algae were determined by using the standard method of OECD. The most toxic compound is 1,2-dinitrobenzene (lg 1/EC_(50) is 5.04), while the least toxic compound is phenol (lg 1/EC_(50) is 2.46). The energy of the lowest unoccupied molecular orbital (E_(LUMO)), the energy of the highest occupied molecular orbital (E_(HOMO)), Van der Waals area (S_(VdW)) and the molecular weight (M_w) of compounds studied were calculated by the quantum chemical method. Quantitative structure-activity relationships (QSARs) were developed with the toxicity and structural parameters of compounds. The toxicity of these compounds to the algae is related mainly to the orbital energy and the steric parameters. The equation (lg 1/EC_(50)=-1.029E_(HOMO)+0.025S_(VdW)-8.322, R~2 (adj)=0.824) was found to fit well and the average relative error was 6.10% for the training set and 6.99% for the test set. Phenols and anilines are polar narcotics, and their toxicity could be related to the steric parameters or hydrophobicity; whereas nitrobenzenes are reactive compounds, may be regarded as pro-electrophiles, yielding the corresponding potentially highly toxic C-nitroso compounds, and their toxicity may be related commonly to the orbital energy.