Oxidative activation of the dietary cancer chemopreventive agent curcumin

描述（由申请人提供）：姜黄素是一种从植物姜黄中分离的多酚，因其抗氧化、抗炎和抗肿瘤生物活性而被公认。目前正在多项临床试验中评估T用于预防或治疗炎症和神经退行性疾病以及肠癌。虽然姜黄素的大量体外靶点已被确定，但其生物活性的精确化学分子机制尚未阐明。我们发现了一种新的，以前未被认识的姜黄素氧化转化，我们已经检测到大量的氧化代谢产物在血浆和肠粘膜后，口服姜黄素给药小鼠。姜黄素的氧化转化是快速的，显著的，并通过反应性中间体产生新的代谢产物，包括醌甲基化物和螺环氧化物中间体。主要的最终产物是姜黄素的二氧合环庚二烯酮衍生物。我们将测试的假设，氧化转化的产品是姜黄素的药理作用的介质。在具体目标1中，我们将确定姜黄素氧化转化的生物学后果。具体而言，我们将分析的机制，抑制还原和氧化IKK蛋白的亲电和亲核姜黄素代谢产物，诱导DNA裂解的拓扑异构酶II的机制，和蛋白质和DNA加合物的形成醌甲基中间体。在具体目标2中，我们将鉴定姜黄素氧化转化的产物和中间体，并确定其形成机制。在具体目标3中，我们将使用新的LC-MS方法，通过同位素标记的标准品进行定量，确定姜黄素及其代谢物的体内代谢，组织分布和药代动力学。氧化活化的概念可能会导致一个新的范式，了解姜黄素的结构和功能，其作为一种治疗CAM剂的临床应用具有重要意义。

DESCRIPTION (provided by applicant): Curcumin, a polyphenol isolated from the plant turmeric, is recognized for its antioxidant, anti-inflammatory and anti-tumorigenic bioactivities. t is currently being evaluated in multiple clinical trials for the prevention or treatment of inflammatory and neurodegenerative diseases, and also for intestinal cancers. Although a large number of in vitro targets of curcumin have been identified, the precise chemical-molecular mechanism(s) of its biological activities have not been elucidated. We have discovered a novel, previously unrecognized oxidative transformation of curcumin, and we have detected abundant levels of the oxidative metabolites in plasma and intestinal mucosa after oral administration of curcumin to mice. The oxidative transformation of curcumin is rapid, prominent, and gives rise to novel metabolites via reactive intermediates, including a quinone methide and a spiro-epoxide intermediate. The major final product is a dioxygenated cyclopentadione derivative of curcumin. We will test the hypothesis that the products of oxidative transformation are mediators of pharmacological effects of curcumin. In Specific Aim 1 we will determine biological consequences of oxidative transformation of curcumin. Specifically, we will analyze the mechanism of inhibition of reduced and oxidized IKKß by electrophilic and nucleophilic curcumin metabolites, the mechanism of induction of DNA cleavage by topoisomerase II, and protein and DNA adduct formation by the quinone methide intermediate. In Specific Aim 2 we will identify the products and intermediates of oxidative transformation of curcumin and determine their mechanism of formation. In Specific Aim 3 we will determine in vivo metabolism, tissue distribution, and pharmacokinetics of curcumin and its metabolites using a novel LC-MS methodology with quantification by isotopically labeled standards. The concept of oxidative activation could result in a new paradigm of understanding the structure and function of curcumin with important implications for its clinical application as a therapeutic CAM agent.