Lou Y R, Lu Y P, Xie J G, Huang M T, Conney A H
Department of Chemical Biology, College of Pharmacy, Rutgers, State University of New Jersey, Piscataway 08854-8020, USA.
Nutr Cancer. 1999;33(2):146-53. doi: 10.1207/S15327914NC330205.
Treatment of SKH-1 mice with ultraviolet B light (UV-B, 30 mJ/cm2) twice a week for 22-23 weeks resulted in tumor-free animals with a high risk of developing malignant and nonmalignant tumors during the next several months in the absence of further UV-B treatment (high-risk mice). In three separate experiments, oral administration of green tea or black tea (4-6 mg tea solids/ml) as the sole source of drinking fluid for 18-23 weeks to these high-risk mice inhibited the formation and decreased the size of nonmalignant squamous cell papillomas and keratoacanthomas as well as the formation and size of malignant squamous cell carcinomas. In one experiment all these inhibitory effects of tea were statistically significant, whereas in the two other experiments many but not all of the inhibitory effects of tea were statistically significant. The decaffeinated teas were inactive or less effective inhibitors of tumor formation than the regular teas, and adding caffeine back to the decaffeinated teas restored biological activity. Oral administration of caffeine alone (0.44 mg/ml) as the sole source of drinking fluid for 18-23 weeks inhibited the formation of nonmalignant and malignant tumors, and this treatment also decreased tumor size in these high-risk mice.
每周两次用紫外线B光（UV-B，30 mJ/cm²）照射SKH-1小鼠，持续22 - 23周，结果产生了无肿瘤的动物，在接下来的几个月中，即使不再进行UV-B照射，这些动物仍有很高的风险发生恶性和非恶性肿瘤（高风险小鼠）。在三个独立实验中，给这些高风险小鼠连续18 - 23周口服绿茶或红茶（4 - 6毫克茶固体/毫升）作为唯一的饮用水来源，可抑制非恶性鳞状细胞乳头瘤和角化棘皮瘤的形成并减小其大小，同时也抑制恶性鳞状细胞癌的形成并减小其大小。在一个实验中，茶的所有这些抑制作用都具有统计学意义，而在另外两个实验中，茶的许多但并非所有抑制作用具有统计学意义。脱咖啡因茶对肿瘤形成的抑制作用不明显或比普通茶效果差，向脱咖啡因茶中重新添加咖啡因可恢复其生物活性。连续18 - 23周给高风险小鼠单独口服咖啡因（0.44毫克/毫升）作为唯一的饮用水来源，可抑制非恶性和恶性肿瘤的形成，并且这种处理还减小了这些高风险小鼠的肿瘤大小。
