title: Synthesis, molecular modeling and biological evaluation of novel tadalafil analogues as phosphodiesterase 5 and colon tumor cell growth inhibitors, new stereochemical perspective.
abstract: The synthesis of novel tadalafil analogues in which the benzodioxole moiety is replaced by 2-bromophenyl; the chiral carbons swing from R,R to R,S, S,R and S,S; the piperazinedione ring is maintained or reduced to the 5-membered imidazolidinedione or thioxoimidazolinone is described. The prepared analogues were evaluated for their capacity to inhibit the cyclic guanosine monophosphate (cGMP) selective phosphodiesterase 5 (PDE5) isozyme and the growth of human HT-29 colon adenocarcinoma cells. The R absolute configuration of C-5 in the beta-carboline-hydantoin and C-6 in the beta-carboline-piperazinedione derivatives was found to be essential for the PDE5 inhibition. In addition, tadalafil analogues that were synthesized from l-tryptophan were more active than those derived from d-tryptophan, which is of economic value and expands the horizon for the discovery of new carbolines as PDE5 inhibitors. While some analogues displayed potent tumor cell growth inhibitory activity, there was no apparent correlation with their PDE5 inhibitory activity, which leads us to conclude that other PDE isozymes or PDE5 splice variants may be involved.
authors.affiliation: Department of Pharmaceutical Chemistry, Faculty of Pharmacy and Biotechnology, German University in Cairo, Cairo 11835, Egypt. ashraf.abadi@guc.edu.eg
authors.forename: Ashraf H
authors.initials: AH
authors.lastname: Abadi
authors.forename: Bernard D
authors.initials: BD
authors.lastname: Gary
authors.forename: Heather N
authors.initials: HN
authors.lastname: Tinsley
authors.forename: Gary A
authors.initials: GA
authors.lastname: Piazza
authors.forename: Mohammad
authors.initials: M
authors.lastname: Abdel-Halim
mesh_terms: D002243:Carbolines / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology*; D002455:Cell Division / Q000187:drug effects*; D003110:Colonic Neoplasms / Q000473:pathology*; D019073:HT29 Cells; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D010726:Phosphodiesterase Inhibitors / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology*; D013055:Spectrophotometry, Infrared; D013237:Stereoisomerism; D000068581:Tadalafil
chemical_list: D002243:Carbolines; D010726:Phosphodiesterase Inhibitors; D000068581:Tadalafil