R Vigneshwari, Anjali S, Rajesh Puspalata, Dash Sasmita
Department of Chemistry, Annamalai University, Chidambaram, Tamil Nadu, India.
Water and Steam Chemistry Division, BARC Facilities, Indira Gandhi Centre for Atomic Research, Kalpakkam, Tamil Nadu, India.
J Biomol Struct Dyn. 2023;41(22):12521-12531. doi: 10.1080/07391102.2023.2192792. Epub 2023 Mar 27.
The present investigation focuses on the role of surfactant and its charge on the interaction of flavonoid Quercetin (QCT) and Bovine serum albumin (BSA). QCT is known to undergo autoxidation in many chemical environments which has different characteristics compared to its non-oxidised structure. In this experiment, two ionic surfactants used. They are anionic surfactant, Sodium dodecyl sulfate (SDS) and Cationic surfactants Cetyl pyridinium bromide (CPB). The characterizations employed are conductivity, FT-IR, UV-visible spectroscopy, Dynamic light scattering (DLS) and Zeta potential measurements. The critical micellar concentration (CMC) as well as the counter-ion binding constant (β) have been calculated by making use of specific conductance values, in aqueous medium at 300 K. Various thermodynamic parameters, ΔG standard free energy of micellization, ΔH, standard enthalpy of micellization and ΔS, standard entropy of micellization are calculated. The negative value of ΔG in all systems is indicative of spontaneous binding occurring in both QCT + BSA + SDS (-23.35 kJ mol) and QCT + BSA + CPB (-27.18 kJ mol). The higher negative value infers the latter is a more stable system with greater spontaneity. The UV-visible spectroscopy study points at stronger binding of QCT and BSA in presence of surfactants and also there is stronger binding of CPB in ternary mixture with higher binding constant compared to SDS ternary mixture. Which is evident from the binding constant calculated from Benesi-Hildebrand plot (QCT + BSA + SDS, 244.46 M; QCT + BSA + CPB, 336.53 M). Further, the structural alterations occurring in the above systems has been observed by FT-IR spectroscopy. The DLS and Zeta potential measurements also support the above finding.Communicated by Ramaswamy H. Sarma.
本研究聚焦于表面活性剂及其电荷对黄酮类化合物槲皮素（QCT）与牛血清白蛋白（BSA）相互作用的影响。已知QCT在许多化学环境中会发生自氧化，与其未氧化结构相比具有不同的特性。在本实验中，使用了两种离子表面活性剂。它们是阴离子表面活性剂十二烷基硫酸钠（SDS）和阳离子表面活性剂十六烷基溴化吡啶（CPB）。所采用的表征方法有电导率、傅里叶变换红外光谱（FT - IR）、紫外可见光谱、动态光散射（DLS）和zeta电位测量。通过在300 K的水性介质中利用电导率值计算了临界胶束浓度（CMC）以及反离子结合常数（β）。计算了各种热力学参数，即胶束化的标准自由能ΔG、胶束化的标准焓ΔH和胶束化的标准熵ΔS。所有体系中ΔG的负值表明在QCT + BSA + SDS（-23.35 kJ/mol）和QCT + BSA + CPB（-27.18 kJ/mol）中都发生了自发结合。较高的负值表明后者是一个更稳定、自发性更强的体系。紫外可见光谱研究表明，在表面活性剂存在下QCT与BSA的结合更强，并且在三元混合物中CPB的结合比SDS三元混合物更强，结合常数更高。这从根据Benesi - Hildebrand图计算的结合常数中可以明显看出（QCT + BSA + SDS，244.46 M；QCT + BSA + CPB，336.53 M）。此外，通过FT - IR光谱观察了上述体系中发生的结构变化。DLS和zeta电位测量也支持上述发现。由Ramaswamy H. Sarma传达。
