Lizárraga Daneida, Touriño Sonia, Reyes-Zurita Fernando J, de Kok Theo M, van Delft Joost H, Maas Lou M, Briedé Jacco J, Centelles Josep J, Torres Josep L, Cascante Marta
Department of Biochemistry and Molecular Biology, unit associated with CSIC, Faculty of Biology, University of Barcelona, Biomedicine Institute of the University of Barcelona, Diagonal 645, E-08028 Barcelona, Spain.
J Agric Food Chem. 2008 Dec 24;56(24):11675-82. doi: 10.1021/jf802345x.
Witch hazel (Hamamelis virginia) extracts are used in traditional medicine. They are particularly rich in gallate esters included in proanthocyanidins, hydrolyzable tannins (galloylated sugars), and methyl gallate. This study examines the response of human colon cancer cells to treatment with fractions obtained from a witch hazel polyphenolic extract. The results are compared with those obtained previously with homologous fractions from grape (less galloylated) and pine (nongalloylated). Witch hazel fractions were the most efficient in inhibiting cell proliferation in HT29 and HCT116 human colon cancer cell lines, which clearly shows that the more galloylated the fractions, the more effective they were at inhibiting proliferation of colon cancer cells. Witch hazel fractions were, in addition, more potent in arresting the cell cycle at the S phase and inducing apoptosis; they also induced a significant percentage of necrosis. Interestingly, the apoptosis and cell cycle arrest effects induced were proportional to their galloylation. Moreover, witch hazel fractions with a high degree of galloylation were also the most effective as scavengers of both hydroxyl and superoxide radicals and in protecting against DNA damage triggered by the hydroxyl radical system. These findings provide a better understanding of the structure-bioactivity relationships of polyphenolics, which should be of assistance in choosing an appropriate source and preparing a rational design for formulations of plant polyphenols in nutritional supplements.
金缕梅（北美金缕梅）提取物被用于传统医学。它们特别富含原花青素中的没食子酸酯、可水解单宁（没食子酰化糖）和没食子酸甲酯。本研究考察了人结肠癌细胞对金缕梅多酚提取物所得组分处理的反应。将结果与先前用葡萄（没食子酰化程度较低）和松树（未没食子酰化）的同源组分所获得的结果进行比较。金缕梅组分在抑制HT29和HCT116人结肠癌细胞系的细胞增殖方面最为有效，这清楚地表明组分的没食子酰化程度越高，它们在抑制结肠癌细胞增殖方面就越有效。此外，金缕梅组分在使细胞周期停滞于S期和诱导细胞凋亡方面更具效力；它们还诱导了相当比例的坏死。有趣的是，诱导的凋亡和细胞周期停滞效应与它们的没食子酰化程度成正比。而且，高度没食子酰化的金缕梅组分作为羟基自由基和超氧阴离子自由基的清除剂以及在保护免受羟基自由基系统引发的DNA损伤方面也是最有效的。这些发现有助于更好地理解多酚类化合物的结构 - 生物活性关系，这对于选择合适的来源以及为营养补充剂中的植物多酚制剂进行合理设计应该会有所帮助。
