Structure Of Bovine Serum Albumin Research Articles

Electron beam-irradiated polypyrrole decorated with Bovine serum albumin pores: Simultaneous determination of epinephrine and L-tyrosine

In current work highly sensitive and stable electrochemical sensor for simultaneous non-enzymatic detection of epinephrine (EP), L-tyrosine (L-Tyr) is constructed based on Electron beam irradiated Polypyrrole (EB-Ppy) nanospheres (Zeta potential 33.69 mV at pH 7) embedded over bovine serum albumin (BSA) (Zeta potential − 11.54 mV at pH 7) porous structure, fabricated by simple chemical routes. The BSA structure has the advantages of large surface area, excellent structure stability, rich pore channels and redox mediator role. The constructed sensor exhibited excellent sensor performances by the combination of protein with NH group and recorded the linear response of EP, L-Tyr individual in the concentration range of 100 nM–1 mM, 100 nM–800 μM, with detection limit 7.1 nM, 8.8 nM (S/N = 3σ/b). The EB-Ppy-BSA/GCE electrochemical sensor manifests intriguing application with good sensitivity, selectivity and reproducibility towards the EP, L-Tyr detection. The practical analytical utility provides great promise by selective measurements in tea, and chicken extract which has a promising future for biological and healthcare applications.

Synthesis and characterization of new unsymmetrical Schiff base Zn (II) and Co (II) complexes and study of their interactions with bovin serum albumin and DNA by spectroscopic techniques

Two novel tetra-coordinated Cobalt(II) and Zinc (II) chelate series with the general formula of [Co (L)·2H2O] (1) and [Zn (L)] (2) [L=N-2-hydroxyacetophenon-N′-2-hydroxynaphthaldehyde-1,2 phenylenediimine)] with biologically active Schiff base ligands were synthesized and recognized by elemental analysis and multi-nuclear spectroscopy (IR and 1H and 13C NMR); then, their biological activities including DNA and protein interactions were studied. The interaction of the synthesized compounds with bovine serum albumin (BSA) was investigated via fluorescence spectroscopy, showing the affinity of the complexes for these proteins with relatively high binding constant values and the changed secondary BSA structure in the presence of the complexes. The interaction of these compounds with CT-DNA was considered by UV–Vis technique, emission titration, viscosity measurements, helix melting methods, and circular dichroism (CD) spectroscopy, confirming that the complexes were bound to CT-DNA by the intercalation binding mode. Furthermore, the complexes had the capability to displace the DNA-bound MB, as shown by the competitive studies of these complexes with methylene blue (MB), thereby suggesting the intercalation mode for the competition. Finally, the theoretical studies carried out by the docking method were performed to calculate the binding constants and recognize the binding site of the BSA and DNA by the complexes. In addition, in vitro and in silico studies showed that the compounds were degradable by bacterial and fungal biodegradation activities.

Impact of the alkyl chain length on binding of imidazolium-based ionic liquids to bovine serum albumin

The effects of six imidazolium-based ionic liquids (ILs) with different alkyl chain length ([CnMim]Cl, n=2, 4, 6, 8, 10, 12) on the structure and functions of bovine serum albumin (BSA) were studied by multi-spectral methods and molecular docking. ILs with the longer alkyl chain length have the stronger binding interaction with BSA and the greater conformational damage to protein. The effects of ILs on the functional properties of BSA were further studied by the determination of non-enzyme esterase activity, β-fibrosis and other properties of BSA. The thermal stability of BSA was reduced, the rate of the formation of beta sheet structures of BSA was lowered, and the esterase-like activity of BSA were decreased with the increase of ILs concentration. Simultaneous molecular modeling technique revealed the favorable binding sites of ILs on protein. The hydrophobic force and polar interactions were the mainly binding forces of them. The calculated results are in a good agreement with the spectroscopic experiments. These studies on the impact of the alkyl chain length on binding of imidazolium-based ionic liquids to BSA are of great significance for understanding and developing the application of ionic liquid in life and physiological system.

Serum Albumin Modulates the Bioactivity of Rosmarinic Acid.

Rosmarinic acid (RA) is a phenolic compound with biological activity. The objective of the present study was to investigate whether this compound kept its biological activity in the presence of proteins. For this purpose, bovine serum albumin (BSA) was used as a model protein, and the capacity of the RA to inhibit acetylcholinesterase (AChE) and affect antioxidant activity was evaluated in the absence and presence of BSA. A mixture of phenolic compounds containing RA, obtained from a medicinal plant was added to this study. The AChE inhibitory activity of RA was reduced by ∼57% in the presence of BSA, while the antioxidant activity increased. These results lead to the investigation of the effect of RA on the BSA structure using Fourier transform infrared spectroscopy (FTIR). At 37°C and higher temperatures, RA caused a decrease in the temperature modifications on the protein structure. Furthermore, FTIR and native-gel analysis revealed that protein aggregation/precipitation, induced by temperature, was reduced in the presence of RA. The novelty of the present work resides in the study of the enzyme inhibitory activity and antioxidant capacity of polyphenols, such as RA, in the presence of a protein. The findings highlight the need to consider the presence of proteins when assessing biological activities of polyphenols in vitro and that enzyme inhibitory activity may be decreased, while the antioxidant capacity remains or even increases.

Nelumbo nucifera leaf extracts inhibit the formation of advanced glycation end-products and mechanism revealed by Nano LC-Orbitrap-MS/MS

The inhibition of Nelumbo nucifera leaf (NNL) extract and its fractions on the formation of advanced glycation end-products (AGEs) was evaluated with different models. Changes in the conformational structure of bovine serum albumin (BSA) were analyzed by fluorescence spectrometry. Effect of ethyl acetate fraction (EAF) on the glycation sites and glycation degree of BSA was investigated by Nano LC-Orbitrap-MS/MS due to its strongest inhibitory ability. Results indicated that EAF could effectively inhibit the formation of AGEs by scavenging reactive radicals and attenuating the conformational change of BSA induced by glycation. Phenolics and flavonoids were the major contributors. Eleven (11 lysines) and ten (9 lysines and 1 arginine) glycation sites were identified from glycated BSA with and without EAF, respectively. Addition of EAF could not reduce the number of glycation sites of BSA, but could significantly decrease the glycation degree of most glycated peptides and alter the location of glycation.

Difference in Binding of Long- and Medium-Chain Fatty Acids with Serum Albumin: The Role of Macromolecular Crowding Effect

Fatty acids (FAs) are transported by serum albumin in plasma. Studies have been undertaken to address the binding of MCFAs or LCFAs to human plasma albumin (HPA) and bovine serum albumin (BSA) by characterizing the binding affinities. Previous research on FA binding to serum albumin was usually performed in dilute solutions that are not sufficiently concentrated for the interpretation of the significance of the results under normal physiological conditions. How macromolecular crowded media affect fatty acids and bovine serum albumin (BSA) binding remains unknown. In this article, we investigated the mechanism of FA-BSA binding in a polyethylene glycol crowding environment by using thermodynamic and spectroscopic methods. Molecular crowding increased the binding constant for saturated medium-chain fatty acids (MCFAs) but significantly decreased the binding constant for unsaturated long-chain FAs. The binding sites tended to increase in all the cases. Further investigation revealed that crowding media might loosen the structure of BSA, facilitating MCFA-BSA binding. This research is useful for understanding the transportation of FAs by BSA under physiological conditions and may also help to control digestion by the eventual incorporation of macromolecular crowding agents into food formulations.

Effect of chain length on the interactions of sodium N-alkyl prolinates with bovine serum albumin: a spectroscopic investigation and molecular docking simulations

The interaction of anionic surfactants with serum albumin has emerged as an important area of research and is considered as a model for gaining fundamental insight into surfactant-protein binding, which is useful in both chemical and biological applications. This study involves the interactions of three synthesized proline-based anionic surfactants of varying chain lengths (C8, C10, and C12) with bovine serum albumin (BSA) using different techniques, including fluorescence, 1H NMR, and FT-IR spectroscopy. The study indicated that the binding of the proline surfactants with BSA followed a static quenching process, with an increase in binding ability upon increasing chain length. FT-IR studies revealed a change in the secondary structure of BSA upon binding with the proline surfactant, while 1H NMR investigations indicated the proximity of the long alkyl chain of the surfactant with tryptophan residues of BSA. Molecular docking studies performed on the three proline surfactants with BSA revealed that the surfactants were able to bind in the vicinity of both tryptophan residues (Trp-213 and Trp-134) with an increase in the free energy of binding while increasing the chain length from C8 to C12. Therefore, this study provided a whole view about the interaction of BSA with anionic proline derived surfactants, which can be used as potential ingredients in pharmaceutical products.

Cationic double chained metallosurfactants: synthesis, aggregation, cytotoxicity, antimicrobial activity and their impact on the structure of bovine serum albumin.

Bovine serum albumin (BSA) is one of the most copious and significant blood proteins with dynamic structure. The understanding of the structural functionality of BSA and its interaction with metal ions is desired for various biological functions. Herein, three different metallosurfactants containing different transition metals and the same hydrophobic tail were engaged to investigate the structural transition of BSA. The metallosurfactants have been prepared by a combination of metal ions (M = Fe, Co and Ni) with cetylpyridinium chloride surfactant via the ligand insertion method and were characterized by elemental, FTIR, 1H-NMR, and thermogravimetric analysis (TGA). The obtained results reveal that insertion of a metal ion perturbs the aggregation behavior of the surfactant. Incorporation of a metal-ion has been found to decrease the CMC value of the surfactant, which has been supported by conductivity, surface tension and small angle X-ray scattering (SAXS). These metallosurfactants were employed to study the interaction and binding mechanism of BSA under physiological conditions. SDS-PAGE analysis points out a weak effect of metallosurfactants on the primary structure of BSA, whereas CD spectra implied a significant change in secondary structure with the decreased α-helical content of BSA. Fluorescence spectroscopy indicates the effect of metallosurfactants on the tertiary structure of BSA, whereas absorption spectra demonstrated static quenching with a blue shift in the presence of metallosurfactants. Moreover, unfolding of BSA in the presence of metallosurfactants has also been confirmed by SAXS studies. The overall results indicate that insertion of the metal ion into the framework of the surfactant structure enhances its protein binding/folding/unfolding abilities, which would be helpful in clinical as well as in life sciences.

Safety of nanoparticles based on albumin-polymer conjugates as a carrier of nucleotides for pancreatic cancer therapy.

Gene therapy through systemic administration is expected to offer significant therapeutic potential against intractable cancers, including pancreatic cancer. One of the requirements for in vivo gene therapy is the development of a gene carrier with a high level of safety, transfection ability and tumour accumulation. Bovine serum albumin (BSA)-poly(2-dimethylaminoethyl methacrylate) (PDMAEMA) conjugation (BSA-PDMAEMA conjugation) could result in the development of a promising gene carrier. This conjugate could preserve the BSA structure well and efficiently condense the nucleotide inside, resulting in the formation of BSA-PDMAEMA nanoparticles that have a polyion complex core and surrounding BSA corona with a size of <100 nm. The nanoparticles that were produced based on BSA-PDMAEMA conjugation possessed good characteristics for use as a gene carrier with good biocompatibility, appropriate blood retention and gene protective properties. Furthermore, the in vivo two-dimensional and three-dimensional biodistribution in a xenograft pancreatic cancer (AsPC-1) model in mice clearly showed that BSA-PDMAEMA nanoparticles accumulated at the tumour site via enhanced permeability and the retention effect. Furthermore, BSA-PDMAEMA nanoparticles, which condensed the active anti-cancer oligonucleotide, ISIS5132, inhibited the growth of cancer in AsPC-1-bearing mice compared to mice which were administered with ISIS5132 alone. The structure of the BSA-PDMAEMA nanoparticles, i.e. the polyion complex core with the BSA corona, would comprehensively contribute to these ideal characteristics for use as a gene carrier. In conclusion, BSA-PDMAEMA nanoparticles could exert a therapeutic effect on intractable pancreatic cancer in vivo, indicating their use as a promising gene carrier.

Effects of selected two noble metal ions in medicine on the structure and activity of bovine serum albumin: A multi-spectral studies

In the present study, the toxic influence of two metallic ions on serum albumin was studied by using fluorescence, UV/vis, circular dichroism spectroscopy, and molecular docking, with the aim of delineating the effects of Pt(II) and Au(III) ions on the secondary and tertiary structure, the transportation function, the thermal stability, and the esterase-like activity of bovine serum albumin (BSA). The conformational change occurring in protein structure was monitored by CD and fluorescence spectroscopy. Pt(II) and Au(III) could react with some functional groups of BSA, making the secondary structure change and increasing the microenvironment around Tyr residues of BSA. The content of α-helix decreased remarkably and the contents of β-sheet, and random coil increased with increasing concentration of Pt(II) or Au(III) ion. Compared with Pt(II) ion, Au(III) ion is more likely to damage the tertiary structure of BSA and a higher number of Tyr residues are affected in Au(III)-BSA system. The fluorescence and UV/vis spectral results indicated the formation of Pt(II)-BSA and Au(III)-BSA complexes. In addition, metal ion binding decreased the ANS binding ability, the reversibility of the thermal unfolding process and the esterase-like activity of BSA. Therefore, this paper is expected to improve the toxicity evaluation mechanism of platinum and gold ions.

Nanodispersion of flavonoids in aqueous DMSO-BSA catalysed by cationic surfactants of variable alkyl chain at T = 298.15 to 308.15 K

Density ρ, sound velocity u, surface tension γ, viscosity η and conductance for (0.01 to 0.10mol·kg−1) alkyltrimethyl ammonium bromide (CnTAB, DTAB n=12, TDTAB n=14 and HDTAB n=16) with (0.999millimol·kg−1) quercetin, apigenin and naringenin flavonoids and (2g·kg−1) bovine serum albumin (BSA) in aqueous 10% DMSO (w/w) at T=298.15, 303.15, 308.15K and p=0.1MPa are reported. The ρ, u, γ and η data have calculated apparent molar volume Vϕ, isentropic compressibility ks, apparent molar isentropic compressibility ks,ϕ, intrinsic viscosity [η] and activation energy E∗, to determine the contribution of methylene (CH2) groups of CnTAB. The γ, surface excess concentration Гmax, molecular surface area Amin, hydrodynamic radius Rh, hydrodynamic volume Vh, friccohesity σ and k on increasing CnTAB alkyl chain length infer higher dispersion. Hydrophobicity of BSA in aq-DMSO with flavonoids is as quercetin<apigenin<naringenin, on the weakening of cohesive forces and increasing intermolecular forces with a decrease in surface tension and increase in viscosity for homogenization. The CnTAB develops stronger electrostatic and hydrophobic interactions with BSA and flavonoids denature native BSA structure. Increasing alkyl chain length has catalysed BSA with flavonoids on mutual interactions strengthening their interacting activities, proven with higher η and lower γ values.

Characterization of molecular structures of theaflavins and the interactions with bovine serum albumin.

In this study, theaflavins (TF1, TF2A, TF2B and TF3) were prepared from black tea and their interaction with bovine serum albumin (BSA) was explored by fluorescence and CD spectroscopy. The results showed that the structures of theaflavins exhibited significant effects on the binding/quenching process, and the binding affinity increased with the increase of molecular weight of theaflavins and the presence of galloyl moiety. The quenching effects showed a sequence as TF3>TF2A>TF2B>TF1, demonstrating the important role of the galloyl moiety on the C-3 position of theaflavins. CD spectra indicated that TF3 in high concentration could change the skeleton structure of BSA and induce the unfolding of BSA secondary structure. The present results provide a new perspective for better understanding of the likely physiological fate of theaflavins and help to control the functional characteristics of food.

The effect of glycation on bovine serum albumin conformation and ligand binding properties with regard to gliclazide

Albumin, the major serum protein, plays a variety of functions, including binding and transporting endogenous and exogenous ligands. Its molecular structure is sensitive to different environmental modifiers, among which glucose is one of the most significant. In vivo albumin glycation occurs under physiological conditions, but it is increased in diabetes. Since bovine serum albumin (BSA) may serve as a model protein in in vitro experiments, we aimed to investigate the impact of glucose-mediated BSA glycation on the binding capacity towards gliclazide, as well as the ability of this drug to prevent glycation of the BSA molecule. To reflect normo- and hyperglycemia, the conditions of the glycation process were established. Structural changes of albumin after interaction with gliclazide (0–14μM) were determined using fluorescence quenching and circular dichroism spectroscopy. Moreover, thermodynamic parameters as well as energy transfer parameters were determined. Calculated Stern-Volmer quenching constants, as well as binding constants for the BSA-gliclazide complex, were lower for the glycated form of albumin than for the unmodified protein. The largest, over 2-fold, decrease in values of binding parameters was observed for the sample with 30mM of glucose, reflecting the poorly controlled diabetic state, which indicates that the degree of glycation had a critical influence on binding with gliclazide. In contrast to significant changes in the tertiary structure of BSA upon binding with gliclazide, only slight changes in the secondary structure were observed, which was reflected by about a 3% decrease of the α-helix content of glycated BSA (regardless of glucose concentration) in comparison to unmodified BSA. The presence of gliclazide during glycation did not affect its progress. The results of this study indicate that glycation significantly changed the binding ability of BSA towards gliclazide and the scale of these changes depended on glucose concentration. It may have a direct impact on the free drug fraction and its pharmacokinetic behavior, including the risk of hypoglycemic episodes or unexpected interactions with other ligands. The use of BSA in examining binding effects upon glycation seems to be good model for preliminary research and may be used to identify a potential drug response in a diabetic state.

Exploring the binding of two potent anticancer drugs bosutinib and imatinib mesylate with bovine serum albumin: spectroscopic and molecular dynamic simulation studies.

Bosutinib (BST) and imatinib mesylate (IMT) are tyrosine kinase inhibitors (TKIs). In view of the importance of these inhibitors in cancer treatment, we investigated the mechanism of interaction between BST/IMT and bovine serum albumin (BSA) using various spectroscopic and molecular docking methods. Fluorescence studies indicated that BST/IMT interacted with BSA without affecting the microenvironment around the residue Trp213 of BSA. The quenching mechanism associated with the BST-BSA and IMT-BSA interactions was determined by performing fluorescence measurements at different temperatures. These results suggested that BST and IMT quenched the fluorescence intensity of BSA through static and dynamic processes, respectively, which was confirmed by time-resolved fluorescence measurements. Evaluation of the thermodynamic parameters ∆H°, ∆S°, and ∆G° suggested that hydrophobic and electrostatic interactions played significant roles in the BST-BSA interaction, while IMT-BSA was stabilized by hydrophobic forces. Competitive experimental results revealed that the primary binding sites for BST and IMT on BSA were sites II and I, respectively. This was supported by the results of molecular docking and dynamic simulation studies. The change in the secondary structure of BSA upon binding with BST/IMT was investigated by 3D fluorescence, absorption, and CD spectroscopic studies. In addition, the influences of β-cyclodextrin and metal ions (Cu2+ and Zn2+) on the binding affinities of BST and IMT to BSA were examined. Graphical abstract Binding of BST and IMT in BSA at site II and site I respectively.

Effect of gamma-irradiation of bovine serum albumin solution on the formation of zigzag film textures

Formation of patterns on the surface of dried films of saline biopolymer solutions is influenced by many factors, including particle size and structure. Proteins may be modified under the influence of ionizing radiation. By irradiating protein solutions with gamma rays, it is possible to affect the formation of zigzag (Z) structures on the film surface. In our study, the films were obtained by desiccation of bovine serum albumin (BSA) solutions, which were irradiated by a 60Co gamma-source at doses ranging from 1Gy to 12kGy. The analysis of the resulting textures on the surface of the films was carried out by calculating the specific length of Z-structures. The results are compared against the absorption and fluorescence spectroscopy and dynamic light scattering (DLS) data. Gamma-irradiation of BSA solutions in the 1–200Gy range practically does not influence the amount of Z-structures on the film surface. The decrease in fluorescence intensity and increase in absorbance intensity point to the destruction of BSA structure at 2 and 12kGy, and DLS shows a more than 160% increase in particle size as a result of BSA aggregation at 2kGy. This prevents the formation of Z-structures, which is reflected in the decrease of their specific length.

Changing the activities and structures of bovine serum albumin bound to graphene oxide

To elucidate the binding mechanism of graphene oxide (GO) with bovine serum albumin (BSA) at molecular level, it is urgent to investigate their interactions in this work. The results indicated that multi noncovalent forces including hydrophobic force, hydrogen bonds, van der Waals and π-π* stacking interactions were involved in the adsorption forces of BSA on GO surface. The kinetics of BSA adsorption onto GO follows the pseudo-second-order kinetic model and was a fast process with high adsorption capacity. Some structure and functions of BSA were changed by GO binding. The decrease of melting temperature (Tm) and enthalpy changes (ΔHm) implied that BSA on GO surface is more prone towards thermal denaturation. Drug competition experimental results showed that the binding affinities of BSA with 1-anilinonaphthalene-8-sulfonic acid (ANS) and ofloxacin (OFLX) were decreased to some extent. The esterase-like activity of BSA was obviously increased and BSA became more glycosylated in the presence of GO. Interestingly it was found that presence of GO significantly induced the conformation and activity changes of BSA. This work should help readers to understand and develop ideas for bio-related applications and to discuss the toxicological effects of graphene materials.

Insight into the interaction between chitosan and bovine serum albumin

Exploiting the uses of proteins and polysaccharides is of increasing interest because the combination of the attributes of these two types of biopolymers can produce small emulsion droplets with good physical stability. The objective of this study was to evaluate the effect of adding chitosan to a bovine serum albumin (BSA) solution at different pH values, and the consequent conformational changes were monitored using UV–vis absorption spectroscopy and fluorescence spectroscopy. Spectroscopic observations were further combined with rheological analysis results to illustrate the interaction mechanism. The results showed that the pH and BSA/chitosan ratio significantly affected the interaction between BSA and chitosan. Additionally, the microenvironment and the secondary structure of BSA were changed with the addition of chitosan, and chitosan was found to quench the intrinsic fluorescence of BSA. The experimental results provide theoretical guidance for the design of new ingredients for the food industry.

A Multiparticulate Delivery System for Potential Colonic Targeting Using Bovine Serum Albumin as a Model Protein : Theme: Formulation and Manufacturing of Solid Dosage Forms Guest Editors: Tony Zhou and Tonglei Li.

There are many important diseases whose treatment could be improved by delivering a therapeutic protein to the colon, for example, Clostridium difficile infection, ulcerative colitis and Crohn's Disease. The goal of this project was to investigate the feasibility of colonic delivery of proteins using multiparticulate beads. In this work, bovine serum albumin (BSA) was adopted as a model protein. BSA was spray layered onto beads, followed by coating of an enteric polymer EUDRAGIT® FS 30 D to develop a colonic delivery system. The secondary and tertiary structure change and aggregation of BSA during spray layering process was examined. The BSA layered beads were then challenged in an accelerated stability study using International Council for Harmonization (ICH) conditions. The in vitro release of BSA from enteric coated beads was examined using United States Pharmacopeia (USP) dissolution apparatus 1. No significant changes in the secondary and tertiary structure or aggregation profile of BSA were observed after the spray layering process. Degradation of BSA to different extents was detected after storing at 25°C and 40°C for 38days. Enteric coated BSA beads were intact in acidic media while released BSA in pH7.4 phosphate buffer. We showed the feasibility of delivering proteins to colon in vitro using multiparticulate system.

Secondary structure transitions of Bovine serum albumin induced by temperature variation

Secondary structure transitions of Bovine Serum Albumin (BSA) in H2O and D2O under temperature variation were investigated by in-situ IR spectral analysis and they were found to exhibit the same tendency with the only difference that the significant transition temperature of BSA's secondary structure moved towards a lower temperature in D2O. Before this significant transition temperature, the native secondary structures of BSA were essentially changing in a cooperative fashion with temperature variation, except for the intermolecular β-sheet (high-wavenumber) which increased as a result of thermal denaturation at a later stage. After the transition temperature, the relative contents of α-helix and extended chain continued to drop sharply and they were transformed into random coil, β-turn and β-sheet.

Interaction of Flavonoids from Woodwardia unigemmata with Bovine Serum Albumin (BSA): Application of Spectroscopic Techniques and Molecular Modeling Methods

Phytochemical investigation on the methanol extract of Woodwardia unigemmata resulted in the isolation of seven flavonoids, including one new flavonol acylglycoside (1). The structures of these compounds were elucidated on the basis of extensive spectroscopic analysis and comparison of literature data. The multidrug resistance (MDR) reversing activity was evaluated for the isolated compounds using doxorubicin-resistant K562/A02 cells model. Compound 6 showed comparable MDR reversing effect to verapamil. Furthermore, the interaction between compounds and bovine serum albumin (BSA) was investigated by spectroscopic methods, including steady-state fluorescence, synchronous fluorescence, circular dichroism (CD) spectroscopies, and molecular docking approach. The experimental results indicated that the seven flavonoids bind to BSA by static quenching mechanisms. The negative ΔH and ΔS values indicated that van der Waals interactions and hydrogen bonds contributed in the binding of compounds 2–6 to BSA. In the case of compounds 1 and 7 systems, the hydrophobic interactions play a major role. The binding of compounds to BSA causes slight changes in the secondary structure of BSA. There are two binding sites of compound 6 on BSA and site I is the main site according to the molecular docking studies and the site marker competitive binding assay.