Antiplasmodial activities of homogentisic acid derivative protein kinase inhibitors isolated from a Vanuatu marine sponge Pseudoceratina sp.
As part of our search for new antimalarial drugs in South Pacific marine sponges, we have looked for inhibitors of Pfnek-1, a specific protein kinase of Plasmodium falciparum. On the basis of promising activity in a preliminary screening, the ethanolic crude extract of a new species of Pseudoceratina collected in Vanuatu was selected for further investigation. A bioassay-guided fractionation led to the isolation of a derivative of homogentisic acid [methyl (2,4-dibromo-3,6-dihydroxyphenyl)acetate, 4a] which inhibited Pfnek-1 with an IC(50) around 1.8 muM. This product was moderately active in vitro against a FcB1 P. falciparum strain (IC(50) = 12 muM). From the same sponge, we isolated three known compounds [11,19-dideoxyfistularin-3 (1), 11-deoxyfistularin-3 (2) and dibromo-verongiaquinol (3)] which were inactive against Pfnek-1. Synthesis and biological evaluation of some derivatives of 4a are reported.
Keywords: Pseudoceratina ; Pfnek-1 ; homogentisic acid derivatives ; Plasmodium falciparum ; Bromotyrosine-Derived Metabolites ; Plasmodium-Falciparum ; Psammaplysilla-Purpurea ; Brominated Metabolites ; Verongida Sponges ; Natural-Products ; Alkaloids ; Chemistry ; Malaria ; Methyltransferase
Record created on 2010-04-14, modified on 2016-08-08