Monascin (MS) is a yellow lipid-soluble azaphilonoid pigment identified from Monascus-fermented products with promising biological activities. This work studied interactions between MS and bovine serum albumin (BSA) as well as their influences on the antioxidant activity of MS. Experimental results demonstrated that the fluorescence emission of BSA was quenched by MS via static quenching mechanism and the formed BSA-MS complex was mainly maintained by hydrophobic and hydrogen bond interactions. Meanwhile, the probable binding pocket of MS located near site I of BSA and the corresponding conformational and structural alterations of BSA were determined. Furthermore, the molecular modeling approach was performed to understand the visual representation of binding mode between BSA and MS. It was noticeable that the BSA-MS complex exhibited reduced DPPH radical-scavenging ability, which might be attributed to the restraining effect of BSA on the relevant reaction pathways involved in antioxidation by MS.

中文翻译：

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莫纳辛与牛血清白蛋白（BSA）结合的分子洞察及其对莫纳辛抗氧化特性的影响。

莫纳辛（MS）是一种黄色的脂溶性氮亲性色素，从红曲霉发酵产品中鉴定出来，具有良好的生物活性。这项工作研究了MS与牛血清白蛋白（BSA）之间的相互作用以及它们对MS抗氧化活性的影响。实验结果表明，MS通过静态猝灭机理将BSA的荧光发射猝灭，形成的BSA-MS络合物主要通过疏水键和氢键相互作用保持。同时，测定了位于BSA位点I附近的MS的可能结合口袋以及BSA的相应构象和结构改变。此外，进行了分子建模方法以了解BSA和MS之间结合模式的视觉表示。