Abstract

Cafaminol, also known as methylcoffanolamine, is a vasoconstrictor and anticatarrhal of the methylxanthine family, which is used as a nasal decongestant. This study aimed to investigate the interaction mechanisms of human serum albumin (HSA) with Cafaminol, through several spectroscopic (fluorescence quenching, UV-visible absorption, and circular dichroism (CD) spectroscopies) and molecular modeling techniques. Stern-Volmer plots were employed to specify the fluorescence quenching mechanism, while the simulation methods were utilized to deduce the approximate binding position of Cafaminol on HSA. On the other hand, thermodynamic parameters, enthalpy and entropy changes, were determined to be, respectively, −105.88 (kJ mol⁻¹) and −282.34 (J mol⁻¹ K⁻¹), using the Van't Hoff equation and analyzed later to specify the main acting forces between Cafaminol and HSA. Overall results revealed the binding of Cafaminol to the site I of HSA, as a result of an enthalpy-driven process, mainly through the van der Waals and hydrogen bonding interactions. Static quenching mechanism was found to be responsible for the fluorescence quenching of HSA in the Cafaminol presence, while the number of binding sites and apparent binding constant were measured accordingly. Docking results proposed that Cafaminol and HSA interact with a binding free energy (ΔG) of −6.5 kcal mol⁻¹

Communicated by Ramaswamy H. Sarma

摘要

Cafaminol，也称为甲基咖啡醇胺，是甲基黄嘌呤家族的血管收缩剂和抗卡他药，用作鼻腔减充血剂。本研究旨在通过多种光谱（荧光猝灭、紫外可见吸收和圆二色性 (CD) 光谱）和分子建模技术研究人血清白蛋白 (HSA) 与咖啡胺醇的相互作用机制。Stern-Volmer 图用于指定荧光猝灭机制，而模拟方法用于推断 Cafaminol 在 HSA 上的大致结合位置。另一方面，热力学参数，焓和熵的变化，分别被确定为 -105.88 (kJ mol ^-1 ) 和 -282.34 (J mol ^-1 K ^-1)，使用 Van't Hoff 方程并在稍后进行分析，以指定 Cafaminol 和 HSA 之间的主要作用力。总体结果显示，由于焓驱动过程，主要通过范德华力和氢键相互作用，Cafaminol 与 HSA 的位点 I 结合。发现静态猝灭机制是导致 HSA 在 Cafaminol 存在下荧光猝灭的原因，同时相应地测量了结合位点的数量和表观结合常数。对接结果表明，Cafaminol 和 HSA 的结合自由能 (ΔG) 为 -6.5 kcal mol ^-1

由 Ramaswamy H. Sarma 传达