Department of Chemistry, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia.
Department of Pharmacognosy, College of Pharmacy, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia.
Int J Mol Sci. 2022 Apr 7;23(8):4078. doi: 10.3390/ijms23084078.
The interaction of the important plasma protein, human serum albumin (HSA), with two monoterpenes found in cumin oil, i.e., cuminaldehyde (4-isopropylbenzaldehyde) and cuminol (4-isopropylbenzyl alcohol), was studied in this paper. Both experimental and computational methods were utilized to understand the mechanism of binding. The UV absorption profile of HSA changes in the presence of both cuminaldehyde and cuminol, due to the interaction between HSA with both monoterpenes. The intrinsic fluorescence intensity of HSA was also quenched on the sequential addition of both ligands, due to change in the microenvironment of the fluorophore present in the former. Quenching of HSA by cuminaldehyde was much higher in comparison to that in the presence of cuminol. Fluorescence quenching data were analyzed using modified Stern-Volmer and Lineweaver-Burk methods, which suggested that the binding mechanism was of a static type for both ligands. In both cases, the binding was favored by the domination of hydrophobic as well as hydrogen bonding/Van der Waals forces. Both ligands partially unfolded the secondary structure of HSA, although the effect of cuminaldehyde was more pronounced, as compared to cuminol. The preferred binding site of cuminaldehyde and cuminol inside HSA was also the same; namely, drug binding site 1, located in subdomain IIA. The study showed that cuminaldehyde binds strongly with albumin as compared to its alcohol counterpart, which is due to the more hydrophobic nature of the former.
本文研究了两种存在于孜然油中的单萜类化合物，即枯茗醛（4-异丙基苯甲醛）和枯茗醇（4-异丙基苯甲醇）与人血清白蛋白（HSA）的相互作用。本研究采用实验和计算方法来理解结合机制。由于 HSA 与两种单萜类化合物的相互作用，HSA 的紫外吸收谱在两者存在的情况下发生变化。由于荧光团微环境的变化，HSA 的本征荧光强度也在两种配体的连续加入下猝灭。与存在枯茗醇相比，HSA 被枯茗醛猝灭的程度要高得多。使用修正的 Stern-Volmer 和 Lineweaver-Burk 方法分析荧光猝灭数据表明，两种配体的结合机制均为静态型。在这两种情况下，结合都有利于疏水作用以及氢键/Van der Waals 力的主导。两种配体都使 HSA 的二级结构部分展开，尽管与枯茗醇相比，枯茗醛的作用更为明显。枯茗醛和枯茗醇在 HSA 内的优先结合部位也相同，即位于亚域 IIA 的药物结合部位 1。研究表明，与醇类化合物相比，枯茗醛与白蛋白的结合更强，这是由于前者具有更强的疏水性。
