Lu Qing-Yi, Arteaga James R, Zhang Qifeng, Huerta Sergio, Go Vay Liang W, Heber David
Center for Human Nutrition, David Geffen School of Medicine, University of California, Los Angeles, CA 90095-1742, USA.
J Nutr Biochem. 2005 Jan;16(1):23-30. doi: 10.1016/j.jnutbio.2004.08.003.
Although the avocado is known as a rich source of monounsaturated fatty acids, there has been far less attention given to its content of other bioactive substances including carotenoids, which might contribute to cancer preventive properties similar to those attributed to other fruits and vegetables. The yellow-green color of the avocado prompted us to study the carotenoid content of this fruit using established methods in our laboratory. The California Hass avocado (Persea americana Mill.) was selected for study, because it is the most commonly consumed variety in the southwest United States. These avocados were found to contain the highest content of lutein among commonly eaten fruits as well as measurable amounts of related carotenoids (zeaxanthin, alpha-carotene, and beta-carotene). Lutein accounted for 70% of the measured carotenoids, and the avocado also contained significant quantities of vitamin E. An acetone extract of avocado containing these carotenoids and tocopherols was shown to inhibit the growth of both androgen-dependent (LNCaP) and androgen-independent (PC-3) prostate cancer cell lines in vitro. Incubation of PC-3 cells with the avocado extract led to G(2)/M cell cycle arrest accompanied by an increase in p27 protein expression. Lutein alone did not reproduce the effects of the avocado extract on cancer cell proliferation. In common with other colorful fruits and vegetables, the avocado contains numerous bioactive carotenoids. Because the avocado also contains a significant amount of monounsaturated fat, these bioactive carotenoids are likely to be absorbed into the bloodstream, where in combination with other diet-derived phytochemicals they may contribute to the significant cancer risk reduction associated with a diet of fruits and vegetables.
尽管鳄梨以富含单不饱和脂肪酸而闻名，但人们对其包括类胡萝卜素在内的其他生物活性物质的关注却少得多，这些物质可能具有与其他水果和蔬菜类似的防癌特性。鳄梨的黄绿色促使我们在实验室中使用既定方法研究这种水果的类胡萝卜素含量。我们选择了加州哈斯鳄梨（Persea americana Mill.）进行研究，因为它是美国西南部最常食用的品种。这些鳄梨被发现是常见食用水果中黄体素含量最高的，同时还含有可测量的相关类胡萝卜素（玉米黄质、α-胡萝卜素和β-胡萝卜素）。黄体素占所测类胡萝卜素的70%，鳄梨还含有大量的维生素E。含有这些类胡萝卜素和生育酚的鳄梨丙酮提取物在体外显示出能抑制雄激素依赖性（LNCaP）和雄激素非依赖性（PC-3）前列腺癌细胞系的生长。用鳄梨提取物培养PC-3细胞会导致G(2)/M期细胞周期停滞，并伴有p27蛋白表达增加。单独的黄体素并不能重现鳄梨提取物对癌细胞增殖的影响。与其他颜色鲜艳的水果和蔬菜一样，鳄梨含有多种生物活性类胡萝卜素。由于鳄梨还含有大量的单不饱和脂肪，这些生物活性类胡萝卜素很可能被吸收进血液中，在那里它们与其他饮食来源的植物化学物质结合，可能有助于显著降低与水果和蔬菜饮食相关的癌症风险。
