cereal ferulate constituents: chemistry and bioavailability as antioxidants

加拿大不仅是世界粮食生产大国，也是世界五大粮食出口国之一。全谷物作为健康食品的选择潜力巨大。全谷物食品在饮食中的有益作用在很大程度上还没有被认识到。直到最近，美国食品和药物管理局才批准了一项健康声明，即含有至少51%成分的全谷物食品。加拿大的食物指南《与加拿大的食物指南一起吃得好》建议增加全谷物的消费。科学家报告称，与全谷物摄入量低的人相比，高全谷物摄入量的人患癌症和心脏病的几率降低。由于全谷物含有丰富的营养和植物化学物质，预防癌症、心血管疾病、糖尿病和肥胖症的潜在生物学机制是多样的。很大一部分植物化学物质以与植物细胞壁结合的形式存在，主要分布在谷粒的外层(麸皮)。我的假设是，阿魏酸通过一种很强的键使多种谷物的植物细胞壁中的多糖和木质素发生交联。这个键在与酚类和健康相关的两个主要问题上是关键的-它决定了酚类物质是否可以被提取，它决定了阿魏酸的生物功效，因为从这个键中解放出来，使它能够通过清除自由基的机制来抵消活性氧物种的破坏性影响。阿魏酸的抗氧化性能将取决于其在肠道吸收的有效性以及随后与靶组织的相互作用。该研究计划的指导原则是，对原料和加工产品中谷物植物化学物质的分子结构-功能关系进行表征，可以使它们在多谷物食品中作为天然抗氧化剂得到增强，协同作用可能会产生更好的健康促进特性。

Canada is not only a world leader in production of grain, but also one of the five major grain exporting countries worldwide. Whole grains hold tremendous potential as healthful food choices. The beneficial effects of whole grain foods in the diet have been largely unrecognized. Only recently has the US Food and Drug Administration allowed a health claim on foods containing at least 51% of ingredients as whole grain. Canada's Food Guide "Eating Well with Canada's Food Guide" recommends increased consumption of whole grains. Scientists have reported reduced cancer and heart disease rates in people with high compared with low whole-grain intakes. The potential biological mechanisms for protection against cancer, cardiovascular disease, diabetes and obesity are diverse since whole grains are rich in nutrients and phytochemicals. A large proportion of phytochemicals is located in bound form to plant cell walls mostly in the outer layers (bran) of the grain. It is my hypothesis that ferulic acid cross-links polysaccharides and lignins in the plant cell walls of a wide range of cereal grains by a strong bond. This bond is pivotal with respect to two major issues associated with phenolics and health - it determines whether phenolics can be extracted or not and it determines the bioefficacy of the ferulic acid since liberation from this bond allows it to counteract the damaging effects of reactive oxygen species via a free radical scavenging mechanism. The antioxidant properties of ferulic acid will depend upon its availability for intestinal absorption and subsequent interaction with target tissues. The guiding principle of the research program is that characterization of the molecular structure - function relationships of grain phytochemicals in raw and processed products can lead to their enhancement as natural antioxidants in multigrain foods where synergistic action will likely result in better health promoting properties.