title: Identification and mechanism of action analysis of the new PARP-1 inhibitor 2″-hydroxygenkwanol A.
abstract: BACKGROUND
  Poly(ADP-ribose) polymerase 1 (PARP-1) activity has been implicated in the pathogenesis of numerous diseases as cancer, inflammation, diabetes and neurodegenerative disorders, therefore the research for new PARP-1 inhibitors is still an active area.
  
  
  METHODS
  To identify new potential PARP-1 inhibitors, we performed a screening of a small-molecule library consisting of polyphenols isolated from plants used in the traditional medicine, by Surface Plasmon Resonance (SPR). Biochemical and cellular assays were performed to confirm SPR results and select the promising candidate(s). Finally, limited proteolysis and ligand docking analyses allowed defining the protein region involved in the interaction with the putative inhibitor(s).
  
  
  RESULTS
  The dimeric spiro-flavonoid 2″-hydroxygenkwanol A, member of a relatively recently discovered class of flavonoids containing a spirane C-atom, has been identified as possible PARP-1 inhibitor. This compound showed a high affinity for the polymerase (KD: 0.32±0.05μM); moreover PARP-1 activity in the presence of 2″-hydroxygenkwanol A was significantly affected both when using the recombinant protein and when measuring the cellular effects. Finally, our study suggests this compound to efficiently interact with the protein catalytic domain, into the nicotine binding pocket.
  
  
  CONCLUSIONS
  2″-hydroxygenkwanol A efficiently binds and inhibits PARP-1 at submicromolar concentrations, thus representing a promising lead for the design of a new class of PARP-1 modulators, useful as therapeutic agents and/or biochemical tools.
  
  
  CONCLUSIONS
  Our study has identified an additional class of plant molecules, the spiro-biflavonoids, with known beneficial pharmacological properties but with an unknown mechanism of action, as a possible novel class of PARP-1 activity inhibitors.
authors.affiliation: Department of Pharmacy, University of Salerno, Via Giovanni Paolo II 132, 84084 Fisciano, SA, Italy. Electronic address: fdalpiaz@unisa.it.
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Dal Piaz
authors.affiliation: Department of Pharmacy, University of Salerno, Via Giovanni Paolo II 132, 84084 Fisciano, SA, Italy.
authors.forename: Piera
authors.initials: P
authors.lastname: Ferro
authors.affiliation: Department of Sciences, University of Basilicata, Via Nazario Sauro 85, 85100 Potenza, SA, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: Vassallo
authors.affiliation: Department of Pharmacy, University of Salerno, Via Giovanni Paolo II 132, 84084 Fisciano, SA, Italy.
authors.forename: Michele
authors.initials: M
authors.lastname: Vasaturo
authors.affiliation: Department of Pharmacy, University of Salerno, Via Giovanni Paolo II 132, 84084 Fisciano, SA, Italy.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Forte
authors.affiliation: Department of Pharmacy, University of Salerno, Via Giovanni Paolo II 132, 84084 Fisciano, SA, Italy.
authors.forename: Maria Giovanna
authors.initials: MG
authors.lastname: Chini
authors.affiliation: Department of Pharmacy, University of Salerno, Via Giovanni Paolo II 132, 84084 Fisciano, SA, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Bifulco
authors.affiliation: Department of Pharmacy, University of Salerno, Via Giovanni Paolo II 132, 84084 Fisciano, SA, Italy. Electronic address: tosco@unisa.it.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Tosco
authors.affiliation: Department of Pharmacy, University of Salerno, Via Giovanni Paolo II 132, 84084 Fisciano, SA, Italy.
authors.forename: Nunziatina
authors.initials: N
authors.lastname: De Tommasi
mesh_terms: D020134:Catalytic Domain; D004353:Drug Evaluation, Preclinical; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D005419:Flavonoids / Q000494:pharmacology*; D006367:HeLa Cells; D006801:Humans; D008958:Models, Molecular; D062105:Molecular Docking Simulation; D000071137:Poly (ADP-Ribose) Polymerase-1; D000067856:Poly(ADP-ribose) Polymerase Inhibitors; D013141:Spiro Compounds / Q000494:pharmacology*; D020349:Surface Plasmon Resonance
chemical_list: C000601376:2''-hydroxygenkwanol A; D004791:Enzyme Inhibitors; D005419:Flavonoids; D000067856:Poly(ADP-ribose) Polymerase Inhibitors; D013141:Spiro Compounds; C499320:PARP1 protein, human; D000071137:Poly (ADP-Ribose) Polymerase-1
keywords: Biflavonoids; Mass spectrometry; Molecular modeling; PARP-1; Plant compounds; Surface Plasmon Resonance