The Cytokine IL-1β and Piperine Complex Surveyed by Experimental and Computational Molecular Biophysics

Abstract

The bioactive piperine, a compound found in some pepper species, has been widely studied because of its therapeutic properties that include the inhibition of an important inflammation pathway triggered by interleukin-1 beta (IL-1β). However, investigation into the molecular interactions between IL-1β and piperine is not reported in the literature. Here, we present for the first time the characterisation of the complex formed by IL-1β and piperine through experimental and computational molecular biophysical analyses. Fluorescence spectroscopy unveiled the presence of one binding site for piperine with an affinity constant of 14.3 × 104 M−1 at 298 K. The thermodynamic analysis indicated that the interaction with IL-1β was spontaneous (∆G = −25 kJ/mol) and, when split into enthalpic and entropic contributions, the latter was more significant. Circular dichroism spectroscopy showed that piperine did not affect IL-1β secondary structure (~2%) and therefore its stability. The set of experimental data parameterized the computational biophysical approach. Through molecular docking, the binding site micro-environment was revealed to be composed mostly by non-polar amino acids. Furthermore, molecular dynamics, along with umbrella sampling, are in agreement with the thermodynamic parameters obtained by fluorescence assays and showed that large protein movements are not present in IL-1β, corroborating the circular dichroism data.

Piperine Reduces Neoplastic Progression in Cervical Cancer Cells by Downregulating the Cyclooxygenase 2 Pathway

“…Molecular docking studies have shown direct binding of piperine to PTGS2 with a score of 5042 kcal/mol [ 71 ]. However, piperine also has a high binding affinity for IL-1β, which has a binding site for piperine with an affinity constant of 14.3 × 104 M −1a 298 K, and spontaneous interaction between these molecules has been observed (∆G = −25 kJ/mol) [ 72 ]. This evidence, together with the results of our study, supports the hypothesis that piperine may have bound to these mediators, preventing the binding of IL-1β to its receptor and the synthesis of PGE2, and resulting in an anti-inflammatory and antitumor effect in the tumor cells ( Figure 8 ).…”

Detailed Characterization of the Cooperative Binding of Piperine with Heat Shock Protein 70 by Molecular Biophysical Approaches

“…Both methods (the binding equilibrium and Hill methods) differed somewhat in terms of the absolute value of the binding constant. This difference found is due to the fact that the binding equilibrium method uses a first order chemical reaction model while the Hill method does not, as discussed previously in the literature [ 16 , 31 , 40 ].…”

A Computational–Experimental Investigation of the Molecular Mechanism of Interleukin-6-Piperine Interaction

“…Related to the thermochemistry of complexation, the process occurred with the absorption of heat (ΔH > 0), being an endothermic process. In addition, both terms T.ΔS and ΔH are positive values that reveal the non-specific interactions as the main interactions that drove the complexation [ 20 , 22 , 23 ]. This information is further reinforced in the molecular modelling section, which points to a single hydrogen bond formed in the complex.…”

“…The molecular structure of piperine ( Figure 1 ) is composed of two groups, electronically conjugated-benzodioxole and pentadienone chromophore [ 19 ]. This structural feature leads to characteristic ultraviolet (UV) absorptions [ 20 ]. A review reported in the literature this year (2022) gathered a set of studies of important targets that interact (experimental and computational results) with piperine [ 21 ].…”

“…Although piperine has exhibited biological activity on the inhibition of the inflammatory NF-κB pathway in cellular and in vivo experiments, the molecular targets and interactions have not been fully disclosed. In our previous studies, we elucidated the mode of binding and affinity of piperine toward some important targets of the NF-κB inflammation pathway, such as Interleukin-1β [ 20 ], nucleotide-binding domain of heat shock protein 70 [ 22 ] and nuclear factor kappa B (NF-κB) [ 15 ]. In order to move forward in our investigations, in this work we present the spectroscopic and computational biophysical characterisation of the IL6-piperine complex to elucidate the main features of the interaction and small-molecule drug discovery efforts in this emerging topic.…”