State Key Laboratory of Food Nutrition and Safety, College of Food Science and Engineering, Tianjin University of Science and Technology, Tianjin 300457, P. R. China.
Beijing Engineering and Technology Research Center of Food Additives, Beijing Technology & Business University (BTBU), Beijing 100048, P. R. China.
Food Funct. 2023 Mar 6;14(5):2459-2471. doi: 10.1039/d2fo02946d.
Ankaflavin (AK) is a typical yellow pigment extracted from -fermented rice with several biological effects; however, its solubility is poor. Thus, research studies of the delivery systems of AK, especially those constructed from protein-polysaccharide complexes, have attracted considerable attention. However, the interactions that exist in the system have rarely been investigated. This work focused on the interactions between AK and bovine serum albumin (BSA) as well as the influence of carrageenan (Car) on the binding of AK to BSA. Results revealed that the quenching of BSA by AK involved the static quenching mechanism. The formed BSA-AK complexes were mainly maintained by hydrophobic forces and AK was located within the hydrophobic cavity of BSA. Compared to free AK or AK only complexed with BSA, a higher absorption intensity of AK was observed for the formed BSA-AK-Car complexes, indicating changes in the microenvironment of AK. This was confirmed by the increase in the α-helix content of BSA after the formation of BSA-AK-Car complexes. Hydrogen bond, van der Waals, and electrostatic interactions were verified to be the primary forces preserving the BSA-AK-Car complexes. Moreover, the antioxidant potential of -fermented products rich in AK (denoted as Mps), namely BSA-Mps and BSA-Mps-Car was evaluated. The antioxidant activity of Mps was negatively impacted by BSA, while the addition of Car could enhance the antioxidant capacity of BSA-Mps-Car complexes. Meanwhile, Mps showed a protective effect against free radical-induced oxidation damage to BSA, and Car could further improve this effect.
安卡黄素（AK）是一种从 -发酵米中提取的典型黄色色素，具有多种生物效应；然而，其溶解度较差。因此，AK 的递药系统，特别是由蛋白质-多糖复合物构建的递药系统的研究引起了相当大的关注。然而，该系统中存在的相互作用很少被研究。本工作重点研究了 AK 与牛血清白蛋白（BSA）之间的相互作用，以及卡拉胶（Car）对 AK 与 BSA 结合的影响。结果表明，AK 对 BSA 的猝灭涉及静态猝灭机制。形成的 BSA-AK 复合物主要通过疏水作用力维持，AK 位于 BSA 的疏水腔中。与游离 AK 或仅与 BSA 复合的 AK 相比，形成的 BSA-AK-Car 复合物中 AK 的吸收强度更高，表明 AK 的微环境发生了变化。这一点通过形成 BSA-AK-Car 复合物后 BSA 的α-螺旋含量增加得到了证实。氢键、范德华力和静电相互作用被证实是保持 BSA-AK-Car 复合物的主要作用力。此外，还评估了富含 AK 的 -发酵产物（表示为 Mps），即 BSA-Mps 和 BSA-Mps-Car 的抗氧化潜力。BSA 降低了 Mps 的抗氧化活性，而 Car 的添加可以增强 BSA-Mps-Car 复合物的抗氧化能力。同时，Mps 对 BSA 自由基诱导氧化损伤表现出保护作用，Car 可以进一步提高这种作用。
