β-胡萝卜素的癌症化学预防机理研究进展

Recent advances for research on chemopreventive effect of β-carotene

癌症是慢病过程顶点 ,是环境与遗传交互作用的结果 ,约 35 %癌症可以通过饮食调节获得预防效果。自然界约有 60 0种仅在植物和微生物体内合成异戊二烯类化合物类胡萝卜素 ,少部分通过水果和蔬菜进入人体组织中 ,补充 β 胡萝卜素可以降低癌症发病率 ,可能与其猝灭单线态氧、抑制过氧基的抗氧化性质有关。而ATBC(维生素E和 β 胡萝卜素 )和CARET(β 胡萝卜素和视黄醇 )试验结果表明补充 β 胡萝卜素增加吸烟和石棉人群癌症发病率 ,这可能是吸烟 石棉暴露造成氧应激 ,由此导致 β 胡萝卜素原氧化 ,从而加剧细胞DNA氧化损伤 ,促进诱导I相代谢活化酶 。

Cancer is the culmination of the chronic disease process, and can be attributed the interactions of environment and genes. An optimistic message for 35% cancer prevention may be in dietary constituents, food supply. Carotenoids are isoprenoid compounds synthesized in plants and microorganisms,but not in animals. Human tissue contains only a fraction of the total number of carotenoids(nearly 600 have been identified in nature) present in food supply such as fruit and vegetables. People with high intake of β Carotene have a reduced risk of cancer. This outcome seems to bear relation to the chemical to quench singlet oxygen and inhibit peroxyl free radical reaction. But the ATBC and CARET cancer prevention study found the increase in lung cancer incidence in smokers and asbestos. This adverse effect may be explained by β Carotene prooxidant when tobacco smoke exposure and oxidative stress occurs, and cellular DNA damage was further aggrevated. Phase I enzymes were induced. Cell transformation was enhanced.