Cytotoxicity Of Quinoxaline And Its Metabolites On Human Liver Cells

Quinoxaline-1,4-dioxides derivatives are known as promote animal growth and potent synthetic antimicrobial agents, they used in the domestic and international industry widely. Olaquindox,carbadox and quinocetone are well known members in this family. Because of potential carcinogenic toxicity, carbadox have been banned in many countries and regions. In aquaculture industry of our country, olaquindox and quinocetone have large market share. But their toxicity, especially in vitro cytotoxicity studies have less reported, not to mention the study of their residual damage. So Chang Liver cells and L-02cells were treatmented with quinocetone,olaquindox, and its metabolites desoxyquinocetone,MQCA. And detect the effect of these four compounds on cell proliferation, DNA damage and cell cycle in human liver cells with different time and dose.1Preparation of Quinoxaline and its metabolitesBased on our laboratory study, we purified the quinocetone, olaquindox by recrystallization, and prepared the desoxyquinocetone and3-methyl-quinoxaline-2-carboxylic acid by chemical synthesis. The reactions of desoxyquinocetone and3-methyl-quinoxaline-2-carboxylic acid by thin layer chromatography. Then determined the content of quinocetone, olaquindox, desoxyquinocetone, MQCA with area normalization method. The result indicated that the content of quinocetone, olaquindox, desoxyquinocetone and MQCA were98.50%,99.28%,98.88%and99.50%respectively.2Cell proliferation of Quinoxaline and their metabolites on Chang Liver and L-02cellsChang Liver cells and L-02cells were treatmented with four compounds. The ratio of cell growth inhibition and the hormesis with different dose and time were evaluated by MTT assay. The result indicated the inhibition ratio of quinocetone and olaquindox in Chang Liver cells were presented by73.29%and31.88%. and in L-02cells were76.51%and39.7%respectively.And The inhibition ratio of desoxyquino-cetone and MQCA in Chang Liver cells were presented by20.02%and22.29%. and in L-02cells were34.49% and22.29%respectively. Four compounds have inhibited with cells, and the result display dose and time dependent manner. In hormesis assay, The value of OD with stimulant group was no significant different with the value of control group, except L-02cells which treatment with quinocetone in the dose of30μg/mL.3Observation on Chang Liver and L-02cells DNA damage caused by Quinoxaline and its metabolitesThe DNA damage of Chang Liver cells and L-02cells induced by four compounds was studied by signe cell gel electrophoresis. The result indicated quinocetone and olaquindox can significantly induced DNA damage on human liver cells (P<0.01), and olaquindox proved to be more deleterious than quinocetone. desoxyquinocetone and MQCA in high doses can also significantly induced DNA damage on human liver cells (P<0.01), and desoxyquinocetone have proved to be more deleterious than MQCA, but the toxicity of these two chemicals were lower than quinocetone and olaquindox.4Effects of Quinoxaline and its metabolites on cell cycle in Chang Liver and L-02cellsThe cell cycle of Chang Liver cells and L-02cells induced by four compounds was studied by flow cytometry. The result indicated after treat with quinocetone and olaquindox, the cycle of two cells were changed, the phase of Go/Gj was higher than the control group, and the cell proliferation was blicked in G0/G1phase. Meanwhile, After treat with desoxyquino-cetone and MQCA, the cell proliferation was blicked in S phase for Chang Liver cells, and the cell proliferation was blicked in G0/G1and G2/M phase for L-02cells.