Nishino H
Department of Biochemistry, Kyoto Prefectural University of Medicine, Kawaramachi-Hirokoji, Kamigyoku, Kyoto 602, Japan.
Mutat Res. 1998 Jun 18;402(1-2):159-63. doi: 10.1016/s0027-5107(97)00293-5.
Epidemiological investigations have shown that cancer risk is inversely related to the consumption of green and yellow vegetables and fruits. Since beta-carotene is present in abundance in these vegetables and fruits, it has been investigated extensively as a possible cancer-preventive agent. However, various carotenoids have also anti-carcinogenic activity. And we found that some of them, such as alpha-carotene, showed higher potency than beta-carotene to suppress carcinogenesis in animal experiments. Thus, we have carried out more extended studies on the cancer-preventive activities of natural carotenoids. For example, lutein, zeaxanthin, lycopene, phytoene, fucoxanthin, peridinin and astaxanthin seem to be promising. In the present study, we confirmed the anti-carcinogenic activities of fucoxanthin and peridinin. Among natural carotenoids, phytoene has not been evaluated precisely since it becomes unstable when it is purified. Here, the cancer-preventive activity of phytoene was demonstrated using new a biotechnological method; i.e., establishment of mammalian cells producing phytoene was followed by the introduction of crtB gene which encodes phytoene synthase, and these cells were proven to acquire the resistance against transformation imposed by transfection of activated oncogenes. Further studies on various natural carotenoids, besides beta-carotene, should be continued to get proper information regarding natural carotenoids in the field of cancer prevention.
流行病学调查表明，癌症风险与绿色和黄色蔬菜及水果的摄入量呈负相关。由于这些蔬菜和水果中富含β-胡萝卜素，因此人们对其作为一种可能的癌症预防剂进行了广泛研究。然而，各种类胡萝卜素也具有抗癌活性。并且我们发现，其中一些，如α-胡萝卜素，在动物实验中显示出比β-胡萝卜素更高的抑制致癌作用的效力。因此，我们对天然类胡萝卜素的防癌活性进行了更广泛的研究。例如，叶黄素、玉米黄质、番茄红素、八氢番茄红素、岩藻黄质、多甲藻素和虾青素似乎都很有前景。在本研究中，我们证实了岩藻黄质和多甲藻素的抗癌活性。在天然类胡萝卜素中，八氢番茄红素由于在纯化时会变得不稳定，尚未得到精确评估。在此，我们采用一种新的生物技术方法证明了八氢番茄红素的防癌活性；即，先建立能够产生八氢番茄红素的哺乳动物细胞，然后导入编码八氢番茄红素合酶的crtB基因，并且这些细胞被证明获得了对激活的癌基因转染所施加的转化的抗性。除了β-胡萝卜素之外，对各种天然类胡萝卜素的进一步研究应该继续进行，以便在癌症预防领域获得有关天然类胡萝卜素的适当信息。
