Studies on the Interaction of Cinnamic Acid with Bovine Serum Albumin

Abstract

Cinnamic acid (3-phenyl-2-propenoic acid, structure shown in Fig. 1) is a compound which can be found in nature. It mainly occurs in flavor compositions and products containing cinnamon oil.1) It has a broad possible therapeutic activities, including antimicrobial activity and antifungal activity.2,3) It was shown that cinnamic acid has antitumor activity against human malignant tumors, such as melanoma, glioblastoma and adenocarcinoma of the prostate and lung. 4) It was also approved its use in cancer prevention and therapy because it has low toxicity in rats and rabbits. 1,5) Serum albumin, one of the most available and extensively studied of all proteins, is the most abundant protein in plasma, accounting for about 60% of its total protein content and providing about 80% of the blood osmotic pressure. It plays an important role in drug transport and storage in vertebrates. 6,7) In the current work, bovine serum albumin (BSA) is selected as our protein model because it is well suited to these initial studies and has been extensively characterized.8) BSA consists of 583 amino acids in a single polypeptide chain. It posses a wide range of physiological functions involving the binding, transport and delivery of fatty acids, porphyrins, bilirubin, tryptophan, thyroxin and steroids. It contains three homologous a-helices domains (I, II and III), and each domain is further divided into two subdomains (IA, IB, etc.).9) It posses two tryptophans embedded in two different domains, one of them is located in the proximity of the protein surface, but buried in a hydrophobic pocket of domain I (Trp-134), whereas the other is located in an internal part of domain II (Trp-214).10) Interactions between cinnamic acid and human serum albumin have been reported using Fourier transformed infrared (FT-IR) spectroscopy.11) But BSA has more widely application than human serum albumin because it is not only suitable for humans but also suitable for other animals, and there is lack of information on the cinnamic acid-BSA binding mode, the binding constant, the effects of cinnamic acid complexation on the protein secondary structure, and the effect of common ions. So in this work, the interaction of cinnamic acid and BSA was studied at physiological pH by fluorescence, CD spectroscopy and FT-IR spectroscopy, and the effect of common ions on drug-BSA system in aqueous solutions at physiological pH have also been investigated. Spectroscopic evidence regarding the drug binding mode, the association constant, and the change of protein secondary structure are provided here. ExperimentalMaterials BSA was purchased from Sino-American Biotechnology Company and used without further purification and its molecular weight was 66210. BSA (1.0ϫ10 Ϫ4 mol/l) solution was prepared in pH 7.40 Tris-HCl buffer solution and kept in the dark at 4°C. Cinnamic acid (analytical grade) was obtained from the National Institute for Control Pharmaceutical and Products, China. Cinnamic acid stock solution (1.0ϫ10 Ϫ3 mol/l) was prepared in ethanol. NaCl (analytical ...

Binding of naturally occurring hydroxycinnamic acids to bovine serum albumin

“…Only slight blue shift and no shift were noticed during interaction of cinnamic acid with BSA and HSA, respectively [1,2]. It can be expected that changes found in emission spectra of HCA-BSA systems were connected with alterations in microenvironment of Trp-134 because Trp-212 in BSA molecule is in the similar position as Trp-214, where cinnamic acid caused no spectral shift of its emission band.…”

“…proteins), especially discussing the thermodynamic quality, binding force quality, and mechanism of interactions [1][2][3]. These studies play crucial role in promoting research on proteins because they can provide useful information for study of pharmacological and biological effects of drugs as well as conformational changes of proteins caused by drugs.…”

“…Spectroscopic techniques, such as ultraviolet-visible (UV-VIS) absorption spectroscopy [17], fluorescence spectroscopy [1,6], circular dichroism [18], and attenuated total reflectance-Fourier transform infrared spectroscopy [19] are commonly used tools to observe conformational changes in structure of proteins because of non-destructive measurements of substances in low concentration under physiological conditions, high sensitivity, rapidity and ease of implementation. Fluorescence spectroscopy is widely used to study mechanism of the binding between drugs and plasma proteins [6].…”

“…Several spectroscopic studies on the interaction between bovine serum albumin and cinnamic acid [1], ferulic acid [20,21], chlorogenic acid [19,22] or various flavonoids [18,19,24] have been published. Also several studies dealing with the interaction of human serum albumin (HSA) with derivatives of cinnamic acid or flavonoids have been carried out [2,3,17,[25][26][27][28][29].…”

Interaction of Bioactive Components Caffeoylquinic Acid Derivatives in Chinese Medicines with Bovine Serum Albumin

“…38) In order to determine the specificity of the CQAs binding and the location of the CQAs-binding sites on BSA, the displacement experiments were carried out according to the literatures, 22,39) using some drugs mentioned above. A 3.0 ml solution of BSA with an appropriate CQAs concentration was titrated by successive addition of warfarin and ibuprofen solutions, respectively.…”