Kandaswami Chithan, Lee Lung-Ta, Lee Ping-Ping H, Hwang Jiuan-Jiuan, Ke Ferng-Chun, Huang Ying-Tung, Lee Ming-Ting
Department of Medicine, State University of New York at Buffalo, New York 12214, USA.
In Vivo. 2005 Sep-Oct;19(5):895-909.
The flavonoids are polyphenolic compounds found as integral components of the human diet. They are universally present as constituents of flowering plants, particularly of food plants. The flavonoids are phenyl substituted chromones (benzopyran derivatives) consisting of a 15-carbon basic skeleton (C6-C3-C6), composed of a chroman (C6-C3) nucleus (the benzo ring A and the heterocyclic ring C), also shared by the tocopherols, with a phenyl (the aromatic ring B) substitution usually at the 2-position. Different substitutions can typically occur in the rings, A and B. Several plants and spices containing flavonoid derivatives have found application as disease preventive and therapeutic agents in traditional medicine in Asia for thousands of years. The selection of a particular food plant, plant tissue or herb for its potential health benefits appears to mirror its flavonoid composition. The much lower risk of colon, prostate and breast cancers in Asians, who consume more vegetables, fruits and tea than populations in the Western hemisphere do, raises the question of whether flavonoid components mediate the protective effects of diets rich in these foodstuffs by acting as natural chemopreventive and anticancer agents. An impressive body of information exists on the antitumor action of plantflavonoids. In vitro work has concentrated on the direct and indirect actions of flavonoids on tumor cells, and has found a variety of anticancer effects such as cell growth and kinase activity inhibition, apoptosis induction, suppression of the secretion of matrix metalloproteinases and of tumor invasive behavior. Furthermore, some studies have reported the impairment of in vivo angiogenesis by dietary flavonoids. Experimental animal studies indicate that certain dietary flavonoids possess antitumor activity. The hydroxylation pattern of the B ring of the flavones and flavonols, such as luteolin and quercetin, seems to critically influence their activities, especially the inhibition of protein kinase activity and antiproliferation. The different mechanisms underlying the potential anticancer action of plant flavonoids await further elucidation. Certain dietary flavonols and flavones targeting cell surface signal transduction enzymes, such as protein tyrosine and focal adhesion kinases, and the processes of angiogenesis appear to be promising candidates as anticancer agents. Further in vivo studies of these bioactive constituents is deemed necessary in order to develop flavonoid-based anticancer strategies. In view of the increasing interest in the association between dietary flavonoids and cancer initiation and progression, this important field is likely to witness expanded effort and to attract and stimulate further vigorous investigations.
黄酮类化合物是作为人类饮食中不可或缺的成分而被发现的多酚类化合物。它们普遍存在于开花植物中，尤其是食用植物中。黄酮类化合物是苯基取代的色酮（苯并吡喃衍生物），由一个15碳的基本骨架（C6-C3-C6）组成，该骨架由一个色满（C6-C3）核（苯环A和杂环C）构成，生育酚也具有该结构，通常在2位有一个苯基（芳香环B）取代。不同的取代通常会发生在A环和B环上。数千年来，几种含有黄酮类衍生物的植物和香料在亚洲传统医学中已被用作疾病预防和治疗药物。选择具有潜在健康益处的特定食用植物、植物组织或草药，似乎反映了其黄酮类成分。亚洲人结肠癌、前列腺癌和乳腺癌的发病率远低于西半球人群，因为亚洲人比西半球人群摄入更多的蔬菜、水果和茶，这就引发了一个问题，即黄酮类成分是否通过作为天然化学预防剂和抗癌剂来介导富含这些食物的饮食的保护作用。关于植物黄酮类化合物的抗肿瘤作用，已有大量令人印象深刻的信息。体外研究主要集中在黄酮类化合物对肿瘤细胞的直接和间接作用上，并发现了多种抗癌作用，如抑制细胞生长和激酶活性、诱导细胞凋亡、抑制基质金属蛋白酶的分泌和肿瘤侵袭行为。此外，一些研究报告了膳食黄酮类化合物对体内血管生成的损害。实验动物研究表明，某些膳食黄酮类化合物具有抗肿瘤活性。黄酮和黄酮醇的B环的羟基化模式，如木犀草素和槲皮素，似乎对它们的活性有至关重要的影响，尤其是对蛋白激酶活性的抑制和抗增殖作用。植物黄酮类化合物潜在抗癌作用的不同机制有待进一步阐明。某些针对细胞表面信号转导酶（如蛋白酪氨酸激酶和粘着斑激酶）以及血管生成过程的膳食黄酮醇和黄酮，似乎有望成为抗癌药物。为了制定基于黄酮类化合物的抗癌策略，有必要对这些生物活性成分进行进一步的体内研究。鉴于人们对膳食黄酮类化合物与癌症发生和发展之间关系的兴趣日益增加，这个重要领域可能会见证更多的努力，并吸引和激发进一步的深入研究。
