Department of Health Sciences, Faculty of Science, University of Mauritius, Réduit, Mauritius.
Toxicology. 2010 Dec 5;278(2):229-41. doi: 10.1016/j.tox.2009.10.010. Epub 2009 Oct 20.
Natural phytochemicals derived from dietary sources or medicinal plants have gained significant recognition in the potential management of several human clinical conditions. Much research has also been geared towards the evaluation of plant extracts as effective prophylactic agents since they can act on specific and/or multiple molecular and cellular targets. Plants have been an abundant source of highly effective phytochemicals which offer great potential in the fight against cancer by inhibiting the process of carcinogenesis through the upregulation of cytoprotective genes that encode for carcinogen detoxifying enzymes and antioxidant enzymes. The mechanistic insight into chemoprevention further includes induction of cell cycle arrest and apoptosis or inhibition of signal transduction pathways mainly the mitogen-activated protein kinases (MAPK), protein kinases C (PKC), phosphoinositide 3-kinase (PI3K), glycogen synthase kinase (GSK) which lead to abnormal cyclooxygenase-2 (COX-2), activator protein-1 (AP-1), nuclear factor-kappaB (NF-κB) and c-myc expression. Effectiveness of chemopreventive agents reflects their ability to counteract certain upstream signals that leads to genotoxic damage, redox imbalances and other forms of cellular stress. Targeting malfunctioning molecules along the disrupted signal transduction pathway in cancer represent a rational strategy in chemoprevention. NF-κB and AP-1 provide mechanistic links between inflammation and cancer, and moreover regulate tumor angiogenesis and invasiveness, indicating that signaling pathways that mediate their activation provide attractive targets for new chemotherapeutic approaches. Thus cell signaling cascades and their interacting factors have become important targets of chemoprevention and phenolic phytochemicals and plant extracts seem to be promising in this endeavor.
天然植物化学物质来源于饮食来源或药用植物，在治疗多种人类临床病症方面具有重要作用。人们还进行了大量研究，评价植物提取物作为有效的预防药物，因为它们可以针对特定的和/或多个分子和细胞靶点发挥作用。植物是高效植物化学物质的丰富来源，通过上调编码致癌物解毒酶和抗氧化酶的细胞保护基因，抑制致癌作用，在抗癌方面具有巨大潜力。化学预防的机制研究还包括诱导细胞周期停滞和细胞凋亡，或抑制信号转导通路，主要是丝裂原活化蛋白激酶（MAPK）、蛋白激酶 C（PKC）、磷酸肌醇 3-激酶（PI3K）、糖原合成酶激酶（GSK），导致异常环氧化酶-2（COX-2）、激活蛋白-1（AP-1）、核因子-κB（NF-κB）和 c-myc 表达。化学预防剂的有效性反映了其对抗某些导致遗传毒性损伤、氧化还原失衡和其他形式细胞应激的上游信号的能力。针对癌症中信号转导途径中断的功能失调分子是化学预防的合理策略。NF-κB 和 AP-1 为炎症和癌症之间提供了机制联系，并且调节肿瘤血管生成和侵袭性，表明介导其激活的信号通路为新的化疗方法提供了有吸引力的靶点。因此，细胞信号级联及其相互作用因子已成为化学预防的重要靶点，酚类植物化学物质和植物提取物在这方面似乎很有前景。
