Nishino H
Cancer Prevention Division, National Cancer Center Research Institute, Tokyo, Japan.
J Cell Biochem Suppl. 1995;22:231-5. doi: 10.1002/jcb.240590829.
As one of the most promising cancer chemopreventive agents, beta-carotene has been studied extensively. However, other natural carotenoids have also suppressed tumorigenesis, and some are more potent than beta-carotene. For example, alpha-carotene shows higher potency than beta-carotene in suppressing tumorigenesis in mouse skin and lung models. In the two-stage mouse skin carcinogenesis model (initiator, 7,12-dimethylbenz[a]anthracene; promoter, 12-O-tetradecanoylphorbol-13-acetate), topical application of alpha-carotene at a 200 nmol dose per painting twice a week significantly decreased the mean number of skin tumors per mouse. The greater potency of alpha-carotene over beta-carotene in suppression of tumor promotion was confirmed in the two-stage mouse lung carcinogenesis model (initiator, 4-nitro-quinoline-1-oxide; promoter, glycerol). Oral administration of alpha-carotene (0.05% in drinking water) significantly decreased the mean number of lung tumors per mouse. In contrast, beta-carotene showed no suppression of lung tumor formation under the same experimental conditions. Fucoxanthin, a carotenoid as abundant in nature as beta-carotene, was also found to have antitumorigenic activity in mouse skin and duodenum models. Thus, further studies on various natural carotenoids, other than beta-carotene, should be carried out in the field of cancer chemoprevention.
作为最有前景的癌症化学预防剂之一，β-胡萝卜素已得到广泛研究。然而，其他天然类胡萝卜素也能抑制肿瘤发生，有些比β-胡萝卜素更有效。例如，在小鼠皮肤和肺部模型中，α-胡萝卜素在抑制肿瘤发生方面表现出比β-胡萝卜素更高的效力。在两阶段小鼠皮肤致癌模型（引发剂，7,12-二甲基苯并[a]蒽；促进剂，12-O-十四酰佛波醇-13-乙酸酯）中，每周两次每次以200 nmol剂量局部涂抹α-胡萝卜素，可显著降低每只小鼠皮肤肿瘤的平均数量。在两阶段小鼠肺癌致癌模型（引发剂，4-硝基喹啉-1-氧化物；促进剂，甘油）中，证实了α-胡萝卜素在抑制肿瘤促进方面比β-胡萝卜素更有效。口服α-胡萝卜素（饮用水中含0.05%）可显著降低每只小鼠肺部肿瘤的平均数量。相比之下，在相同实验条件下，β-胡萝卜素对肺部肿瘤形成没有抑制作用。岩藻黄质是一种在自然界中与β-胡萝卜素一样丰富的类胡萝卜素，在小鼠皮肤和十二指肠模型中也被发现具有抗肿瘤活性。因此，在癌症化学预防领域，应该对除β-胡萝卜素之外的各种天然类胡萝卜素进行进一步研究。
