title: 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.
authors: a Department of Plant Sciences, School of Life Sciences , University of Hyderabad , Hyderabad 500046 , India.
authors: Daniel Pushparaju
authors: DP
authors: Yeggoni
authors: Aparna
authors: A
authors: Rachamallu
authors: Monika
authors: M
authors: Kallubai
authors: Rajagopal
authors: R
authors: Subramanyam
mesh_terms: D000465:Algorithms; D000470:Alkaloids / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology; D000818:Animals; D000893:Anti-Inflammatory Agents / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D052117:Benzodioxoles / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology; D001665:Binding Sites; D002460:Cell Line; D002942:Circular Dichroism; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D008264:Macrophages / Q000187:drug effects / Q000378:metabolism; D051379:Mice; D008962:Models, Theoretical; D062105:Molecular Docking Simulation; D056004:Molecular Dynamics Simulation; D009961:Orosomucoid / Q000737:chemistry* / Q000378:metabolism; D010880:Piperidines / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology; D053284:Polyunsaturated Alkamides / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology; D011485:Protein Binding; D011487:Protein Conformation; D055550:Protein Stability; D017433:Protein Structure, Secondary; D012709:Serum Albumin / Q000737:chemistry* / Q000378:metabolism; D013816:Thermodynamics
chemical_list: D000470:Alkaloids; D000893:Anti-Inflammatory Agents; D052117:Benzodioxoles; D009961:Orosomucoid; D010880:Piperidines; D053284:Polyunsaturated Alkamides; D012709:Serum Albumin; C008922:piperine
keywords: cytotoxicity; drug binding; fluorescence quenching; human serum albumin; molecular dynamics simulation; piperine; α-1-acid glycoprotein