Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2023 Dec 7;24(24):17222.
doi: 10.3390/ijms242417222.

Anti-Aggregative and Protective Effects of Vicenin-2 on Heat and Oxidative Stress-Induced Damage on Protein Structures

Giuseppe Tancredi Patanè  1 , Lisa Lombardo  1 , Stefano Putaggio  1 , Ester Tellone  1 , Silvana Ficarra  1 , Davide Barreca  1 , Giuseppina Laganà  1 , Laura De Luca  1 , Antonella Calderaro  1
Affiliations

Anti-Aggregative and Protective Effects of Vicenin-2 on Heat and Oxidative Stress-Induced Damage on Protein Structures

Giuseppe Tancredi Patanè et al. Int J Mol Sci. .

Abstract

Vicenin-2, a flavonoid categorized as a flavones subclass, exhibits a distinctive and uncommon C-glycosidic linkage. Emerging evidence challenges the notion that deglycosylation is not a prerequisite for the absorption of C-glycosyl flavonoid in the small intestine. Capitalizing on this experimental insight and considering its biological attributes, we conducted different assays to test the anti-aggregative and antioxidant capabilities of vicenin-2 on human serum albumin under stressful conditions. Within the concentration range of 0.1-25.0 μM, vicenin-2 effectively thwarted the heat-induced HSA fibrillation and aggregation of HSA. Furthermore, in this study, we have observed that vicenin-2 demonstrated protective effects against superoxide anion and hydroxyl radicals, but it did not provide defense against active chlorine. To elucidate the underlying mechanisms, behind this biological activity, various spectroscopy techniques were employed. UV-visible spectroscopy revealed an interaction between HSA and vicenin-2. This interaction involves the cinnamoyl system found in vicenin-2, with a peak of absorbance observed at around 338 nm. Further evidence of the interaction comes from circular dichroism spectrum, which shows that the formation of bimolecular complex causes a reduction in α-helix structures. Fluorescence and displacement investigations indicated modifications near Trp214, identifying Sudlow's site I, similarly to the primary binding site. Molecular modeling revealed that vicenin-2, in nonplanar conformation, generated hydrophobic interactions, Pi-pi stacking, and hydrogen bonds inside Sudlow's site I. These findings expand our understanding of how flavonoids bind to HSA, demonstrating the potential of the complex to counteract fibrillation and oxidative stress.

Keywords: anti-aggregative properties; molecular modeling; protective effects against oxidative stress; spectroscopic analysis; vicenin-2.

PubMed Disclaimer

Conflict of interest statement

The authors declare no conflict of interest.

Figures

Figure 1
Figure 1
(A) Representative fluorescence microscopy images of HSA fibrils in the absence or presence (0.0–25.0 µM) of vicenin-2. (B) UV-visible spectra of Congo red alone or with HSA treated at high temperature. (C) Variation in the maximum absorbance of Congo red–HSA in the absence or presence of 0.0–25.0 µM of vicenin-2 after treatment to induce fibrillation. (a) HSA alone incubated at 338 K; (b) HSA alone incubated at 310 K. Asterisks (**) indicate a significant difference with respect to control (p < 0.05).
Figure 2
Figure 2
The impact of vicenin-2 on protein degradation induced by superoxide anion, hydroxyl radical, and active chlorine. HSA was subjected to electrophoretic separation on polyacrylamide gel electrophoresis (PAGE), with incubation in the absence or presence of different radical alone, or with the addition of 12.5–100.0 μM of the flavonoid. The samples were subjected a 40 min incubation at 310 K and were subsequently analyzed by 7.5% polyacrylamide-gel electrophoresisThe integrated density of each band is presented as a percentage of the untreated HSA sample in the experiments involving superoxide anion, hydroxyl radical, and active chlorine. The histograms depict the data as means ± S.D. (n = 3). Asterisks (**) indicate a significant difference with respect to control (p < 0.05).
Figure 3
Figure 3
UV-visible absorption spectra of vicenin-2 (— 76.5 µM) in the absence or presence of increasing HSA concentrations (— 9.4 µM, — 18.8 µM, — 37.7 µM, — 75.5 µM). The inset shows the variation of absorbance obtained with three different experiments at the maximum absorbance of Band I. Asterisks (**) indicate a significant difference with respect to control (p < 0.05).
Figure 4
Figure 4
Fluorescence emission spectra of HSA (1.5 × 10−5 mol/L) in the absence or presence of the same molar concentration (1.5 × 10−5 mol/L) of vicenin-2 at 298 K and the maximum tested concentration of the flavonoid (A). Stern–Volmer (B) and modified Stern–Volmer (C) plots for the vicenin-2–HSA complex at three different temperatures. Analysis of binding equilibrium, thermodynamics, and acting forces. Plots of log(F0 − F)/F as a function of log[Q] for the binding of vicenin-2 to HSA at the temperature of 310 K (D), as well as van’t Hoff plot (E) and effect of site-specific markers on the fluorescence of HSA–vicenin-2 complex (F). Data are the results of three different experiments, expressed as mean ± SD.
Figure 5
Figure 5
Superimposition of the crystalized warfarin (yellow sticks) to the rigid docking (A) and the induced fit docking (B) poses (purple sticks).
Figure 6
Figure 6
An overview of the HSA 3D structure and identification of Sudlow’s site I (A). Magnification focused on the binding site and the interactions of the vicenin-2 with the residues forming the pockets (B).
Figure 7
Figure 7
The plots of RMSD of the complex HSA–vicenin-2 (A) and the free HSA (B). On the x-axis, the simulation time is depicted. The left y-axis illustrates the HAS RMSD progression, while the y-axis on the right plots the RMSD evolution of vicenin-2 within the binding site during the simulation, indicating the degree of stability exhibited by vicenin-2.
Figure 7
Figure 7
The plots of RMSD of the complex HSA–vicenin-2 (A) and the free HSA (B). On the x-axis, the simulation time is depicted. The left y-axis illustrates the HAS RMSD progression, while the y-axis on the right plots the RMSD evolution of vicenin-2 within the binding site during the simulation, indicating the degree of stability exhibited by vicenin-2.
Figure 8
Figure 8
Molecular interaction in the complex. (A) Protein–ligand interactions are classified into four categories distinguishable by the color of the bars: hydrophobic interactions (purple), hydrogen bonds (green), ionic contacts (fuchsia), and water bridges (blue). (B) An in-depth examination of the contacts between ligand atoms and residues, considering interactions that occur more than 40% of the time.
Figure 9
Figure 9
CD spectra of free HSA and the vicenin-2/HSA complex at T = 298 K in phosphate buffer of pH 7.4, 20 mM.
See this image and copyright information in PMC

Similar articles

See all similar articles

References

    1. Zoll L. Proteomics studies reveal important information on small molecule therapeutics: A case study on plasma proteins. Drug Discov. Today. 2008;13:23–24. doi: 10.1016/j.drudis.2008.09.013. - DOI - PMC - PubMed
    1. Fabini E., Danielson U. Monitoring drug–serum protein interactions for early ADME prediction through Surface Plasmon Resonance technology. J. Pharm. Biomed. Anal. 2017;144:188–194. doi: 10.1016/j.jpba.2017.03.054. - DOI - PubMed
    1. Calderaro A., Maugeri A., Magazù S., Laganà G., Navarra M., Barreca D. Molecular Basis of Interactions between the Antibiotic Nitrofurantoin and Human Serum Albumin: A Mechanism for the Rapid Drug Blood Transportation. Int. J. Mol. Sci. 2021;22:8740. doi: 10.3390/ijms22168740. - DOI - PMC - PubMed
    1. Mishra V., Heath R.J. Structural and Biochemical Features of Human Serum Albumin Essential for Eukaryotic Cell Culture. Int. J. Mol. Sci. 2021;22:8411. doi: 10.3390/ijms22168411. - DOI - PMC - PubMed
    1. Barreca D., Laganà G., Toscano G., Calandra P., Kiselev M.A., Lombardo D., Bellocco E. The interaction and binding of flavonoids to human serum albumin modify its conformation, stability and resistance against aggregation and oxidative injuries. Biochim. Biophys. Acta Gen. Subj. 2017;1861 Pt B:3531–3539. doi: 10.1016/j.bbagen.2016.03.014. - DOI - PubMed

Grants and funding

This research received no external funding.
-