Phenolics and polyphenolic compounds in food and as functional food ingredients: characterization, mechanism(s) of action, structure modification and process effects

流行病学研究表明，食用植物性食物与降低退行性疾病，特别是动脉粥样硬化、炎症性疾病和某些类型的癌症的风险有关。产生这种作用的植物成分由无数种化合物代表，其中一类主要是具有抗氧化作用的生物活性酚类物质和多酚类物质。因此，必须确定这些生物活性物质的采购和鉴定，并检查其特性和生理益处，以便为其功效提供可信的证据。酚类物质和多酚类物质在促进健康和降低疾病风险中的作用机制包括一系列复杂的事件。因此，清除自由基和活性氧，防止低密度脂蛋白（LDL）胆固醇（心脏病的罪魁祸首）的氧化，延缓导致癌症的DNA分解和突变，以及抑制过量一氧化氮的产生及其有害影响，都需要仔细研究。此外，糖尿病、白内障、神经病变等的晚期糖基化终点（age）是已知酚类/多酚类物质促进健康的其他机制之一。由于食品是连续消费的，因此，通过不同的加工操作或通过农业做法进行强化，或在食品制备过程中保留或改善吸收和生物利用度，使食品富含有益健康的成分是至关重要的。某些生物活性物质也可以被提取出来，用作保健品/天然保健品。这项工作将为揭示存在的重要酚类和多酚类化合物的身份，其含量和由于加工或改性而产生的活性变化提供必要的信息。此外，这些生物活性物质的作用机制将被揭示，以填补现有文献中的空白。因此，这项工作的结果将提供基本的科学信息，并导致实际应用，可能通过预防和可能的治疗手段有助于降低保健费用。

Epidemiological studies have demonstrated that the consumption of plant foods is associated with reduced risk of degenerative diseases, particularly atherosclerosis, inflammatory diseases and certain types of cancer. Plant components responsible for such effects are represented by a myriad of compounds, a major class being bioactive phenolics and polyphenolics that render antioxidant effects, among others. Thus, procurement and identification of such bioactives and examination of their properties and physiological benefits must be established in order to provide credible evidence for their efficacy. The mechanism(s) of action of phenolics and polyphenolics in health promotion and disease risk reduction includes a multiple and complex series of events. Thus, scavenging of free radicals and reactive oxygen species, preventing oxidation of low-density lipoprotein (LDL) cholesterol, a culprit in heart disease, retarding breakdown of DNA and mutation, responsible for cancer, and inhibition of excess nitric oxide production with its deleterious effects need to be examined carefully. In addition, advanced glycation endpoints (AGEs) responsible for diabetes, cataract, neuropathy and alike are among the other mechanisms by which phenolics/polyphenolics are known to promote health. Since foods are consumed on a continuous basis, their enrichment with health beneficial components, via different processing operations or enhancement through agricultural practices, or retention during food preparation or improved absorption and bioavailability are of utmost importance. Certain bioactives may also be extracted and used as nutraceuticals/natural health products. This work would provide the necessary information for unraveling the identity of important phenolic and polyphenolic compounds present, their content and changes due to processing or modification for activity enhancement. In addition, mechanisms of actions of such bioactives will be unraveled in order to fill the existing gap in the available literature. Findings of this work would thus provide fundamental scientific information and also leads to practical applications which may contribute to health care cost reduction through preventive and possibly therapeutic means.