Numerous studies have shown, rather disappointingly, that isolated bioactive phytochemicals are not as biologically effective as natural plant products. Such a discrepancy may be explained by the concept of food synergy, which was verified in this research for cocoa extract versus its major components with regard to cancer chemoprevention. The evaluation embraced the relationship between redox properties evaluated in cell-free systems with the aid of free radicals scavenging method and differential pulse voltammetry, and redox associated anticarcinogenic activities (cellular antioxidant activity, cytotoxicity, nutrigenomic activity) in human colon adenocarcinoma cell line exposed to either cocoa powder extract or artificial mixtures of cocoa bioactives at matching concentrations. In contrast to expectations, our results showed that the stepwise enrichment with antioxidants caused no gradual increase in the antioxidant activity of the model mixtures; also, these model mixtures did not reach the reducing potential of cocoa in the cell-free systems or cellular model employed. Further, the biological activities examined in colon adenocarcinoma cells did not alter in a stepwise manner that could reflect the gradual changes in composition of bioactive ingredients. In conclusion, the experiments presented here showed that the growing complexity of a mixture of phytochemicals seems to create a new redox bioactive substance rather than enrich the mixture with new activities, characteristic of the compound added. It follows that no simple, predictable relationship can be expected between the chemopreventive potential and the composition of real food items containing a complicated set of non-toxic redox active ingredients. Our observations suggest that the interactions between different bioactive compounds and food matrix components are cooperating factors determining the final bioactivity of foods.

中文翻译：

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生物活性成分之间的相互作用决定了可可粉提取物的抗氧化剂，细胞毒性和营养营养活性。

令人失望的是，许多研究表明，分离出的生物活性植物化学物质在生物学上没有天然植物产品有效。这种差异可以用食物协同作用的概念来解释，该研究在可可提取物中与其在化学预防中的主要成分之间的关​​系在本研究中得到了证实。评估涵盖了在无细胞系统中通过自由基清除方法和差分脉冲伏安法评估的氧化还原特性与暴露于人结肠腺癌细胞系的氧化还原相关抗癌活性（细胞抗氧化活性，细胞毒性，营养学活性）之间的关系。可可粉提取物或可匹配浓度的可可生物活性成分的人工混合物。与期望相反，我们的研究结果表明，逐步添加抗氧化剂不会使模型混合物的抗氧化活性逐渐增加。同样，在使用的无细胞系统或细胞模型中，这些模型混合物未达到可可的还原潜力。此外，在结肠腺癌细胞中检查的生物活性没有以逐步的方式改变，这可以反映出生物活性成分组成的逐渐变化。总之，此处提出的实验表明，植物化学混合物的日益复杂性似乎在创造一种新的氧化还原生物活性物质，而不是使混合物具有新的活性，这是添加的化合物的特征。因此，没有简单的方法，在化学预防潜力和包含复杂的无毒氧化还原活性成分的真实食品成分之间，可以预期存在可预测的关系。我们的观察结果表明，不同生物活性化合物与食物基质成分之间的相互作用是决定食物最终生物活性的协同因素。