title: Structurally diverse metal coordination compounds, bearing imidodiphosphinate and diphosphinoamine ligands, as potential inhibitors of the platelet activating factor.
abstract: Metal complexes bearing dichalcogenated imidodiphosphinate [R(2)P(E)NP(E)R(2)'](-) ligands (E = O, S, Se, Te), which act as (E,E) chelates, exhibit a remarkable variety of three-dimensional structures. A series of such complexes, namely, square-planar [Cu{(OPPh(2))(OPPh(2))N-O, O}(2)], tetrahedral [Zn{(EPPh(2))(EPPh(2))N-E,E}(2)], E = O, S, and octahedral [Ga{(OPPh(2))(OPPh(2))N-O,O}(3)], were tested as potential inhibitors of either the platelet activating factor (PAF)- or thrombin-induced aggregation in both washed rabbit platelets and rabbit platelet rich plasma. For comparison, square-planar [Ni{(Ph(2)P)(2)N-S-CHMePh-P, P}X(2)], X = Cl, Br, the corresponding metal salts of all complexes and the (OPPh(2))(OPPh(2))NH ligand were also investigated. Ga(O,O)(3) showed the highest anti-PAF activity but did not inhibit the thrombin-related pathway, whereas Zn(S,S)(2), with also a significant PAF inhibitory effect, exhibited the highest thrombin-related inhibition. Zn(O,O)(2) and Cu(O,O)(2) inhibited moderately both PAF and thrombin, being more effective towards PAF. This work shows that the PAF-inhibitory action depends on the structure of the complexes studied, with the bulkier Ga(O,O)(3) being the most efficient and selective inhibitor.
authors.affiliation: Biochemistry Laboratory, Faculty of Chemistry, National and Kapodistrian University of Athens, Panepistimiopolis, Zografou, 15771 Athens, Greece.
authors.forename: Alexandros B
authors.initials: AB
authors.lastname: Tsoupras
authors.forename: Maria
authors.initials: M
authors.lastname: Roulia
authors.forename: Eleftherios
authors.initials: E
authors.lastname: Ferentinos
authors.forename: Ioannis
authors.initials: I
authors.lastname: Stamatopoulos
authors.forename: Constantinos A
authors.initials: CA
authors.lastname: Demopoulos
authors.forename: Panayotis
authors.initials: P
authors.lastname: Kyritsis