Yoon Hyungeun, Liu Rui Hai
Department of Food Science, Cornell University, Ithaca, New York 14853-7201, USA.
J Agric Food Chem. 2008 Sep 24;56(18):8412-7. doi: 10.1021/jf8012844. Epub 2008 Aug 14.
Apples are one of the largest contributors of fruit phenolics of all fruits consumed by Americans and contain a variety of bioactive compounds, which have health benefits. Consumption of apples has been linked to reduced risk of chronic diseases such as cancer and cardiovascular disease. Apple extracts have been shown to have the capabilities of inhibiting NF-kappaB activation in human breast cancer MCF-7 cells. 2Alpha-hydroxyursolic acid is one of the major triterpenoids isolated from apple peels, and its effects on cell proliferation and TNF-alpha-induced NF-kappaB activation in MCF-7 cells were examined. 2Alpha-hydroxyursolic acid significantly inhibited MCF-7 cell proliferation at doses of 20 microM (p < 0.05). Preincubation with 2alpha-hydroxyursolic acid suppressed TNF-alpha-induced NF-kappaB activation in a dose-dependent manner and significantly inhibited the activation at a dose of 20 microM of 2alpha-hydroxyursolic acid (p < 0.05). 2Alpha-hydroxyursolic acid treatment did not affect the phosphorylation level of NF-kappaB inhibitor (IkappaB-alpha), but proteasome activity in MCF-7 cells was inhibited significantly at doses of 10 and 20 microM ( p < 0.05). These results suggest that 2alpha-hydroxyursolic acid has antiproliferative activities against MCF-7 cells and capabilities inhibiting NF-kappaB activation induced by TNF-alpha partially by suppressing proteasome activities.
苹果是美国人食用的所有水果中水果酚类物质的最大贡献者之一，并且含有多种生物活性化合物，这些化合物对健康有益。食用苹果与降低患癌症和心血管疾病等慢性疾病的风险有关。苹果提取物已被证明具有抑制人乳腺癌MCF-7细胞中NF-κB活化的能力。2α-羟基熊果酸是从苹果皮中分离出的主要三萜类化合物之一，研究了其对MCF-7细胞增殖和TNF-α诱导的NF-κB活化的影响。2α-羟基熊果酸在20μM剂量时显著抑制MCF-7细胞增殖（p<0.05）。预先用2α-羟基熊果酸孵育以剂量依赖性方式抑制TNF-α诱导的NF-κB活化，并且在20μM的2α-羟基熊果酸剂量时显著抑制活化（p<0.05）。2α-羟基熊果酸处理不影响NF-κB抑制剂（IkappaB-α）的磷酸化水平，但在10和20μM剂量时显著抑制MCF-7细胞中的蛋白酶体活性（p<0.05）。这些结果表明，2α-羟基熊果酸对MCF-7细胞具有抗增殖活性，并且部分通过抑制蛋白酶体活性而具有抑制TNF-α诱导的NF-κB活化的能力。
