Cytotoxicity and comparative binding mechanism of piperine with human serum albumin and α-1-acid glycoprotein

Abstract

Human serum albumin (HSA) and α-1-acid glycoprotein (AGP) (acute phase protein) are the plasma proteins in blood system which transports many drugs. To understand the pharmacological importance of piperine molecule, here, we studied the anti-inflammatory activity of piperine on mouse macrophages (RAW 264.7) cell lines, which reveals that piperine caused an increase in inhibition growth of inflammated macrophages. Further, the fluorescence maximum quenching of proteins were observed upon binding of piperine to HSA and AGP through a static quenching mechanism. The binding constants obtained from fluorescence emission were found to be K(piperine) = 5.7 ± .2 × 10(5) M(-1) and K(piperine) = 9.3± .25 × 10(4) M(-1) which correspond to the free energy of -7.8 and -6.71 kcal M(-1)at 25 °C for HSA and AGP, respectively. Further, circular dichrosim studies revealed that there is a marginal change in the secondary structural content of HSA due to partial destabilization of HSA-piperine complexes. Consequently, inference drawn from the site-specific markers (phenylbutazone, site I marker) studies to identify the binding site of HSA noticed that piperine binds at site I (IIA), which was further authenticated by molecular docking and molecular dynamic (MD) studies. The binding constants and free energy corresponding to experimental and computational analysis suggest that there are hydrophobic and hydrophilic interactions when piperine binds to HSA. Additionally, the MD studies have showed that HSA-piperine complex reaches equilibration state at around 3 ns, which prove that the HSA-piperine complex is stable in nature.

Evaluation of pendimethalin binding to human serum albumin: Insights from spectroscopic and molecular modeling approach

“…A significant change in these signals reflected tertiary structural alteration of the protein . The increase in the thermal stability of HSA in the presence of PM is due to stabilization of the PM–HSA complex by the noncovalent forces, which required higher temperature to be broken down . Such an increase in the thermal stability of HSA in the presence of ligand has been reported earlier …”

Comparative study of the interactions between bisphenol analogues and serum albumins by electrospray mass spectrometry and fluorescence spectroscopy

“…Serum albumins play an important physiological role in the transportation and delivery of various small molecule ligands . Furthermore, binding of small molecules to serum albumins may affect the absorption, distribution, metabolism, and excretion of those compounds in vivo . The blood levels of bisphenols in mammals are associated with acute toxicity and endocrine‐disrupting activity through influencing the circulation of compounds and increasing the plasma half‐life .…”

Elucidating the binding interaction of andrographolide with the plasma proteins: biophysical and computational approach

“…Our group has extensively studied the interaction of various phytochemicals with serum proteins, and has observed that most of the phytochemicals bind strongly to HSA, [10][11][12] but only some of them bind to AGP. 13,14 Andrographolide (ANDR) is a labdane diterpenoid, which is the main bioactive component of the medicinal plant Andrographis paniculata. 15 ANDR has been reported to have a wide range of biological activities, such as anti-inammatory, 16 anti-allergic, 17 anti-platelet aggregation, 18 hepatoprotective, 19 and anti-HIV properties.…”