Design, Synthesis, and Antiviral Activity of Novel Ribonucleosides of 1,2,3-Triazolylbenzyl-aminophosphonates

Ouahrouch, Abdelaaziz; Taourirte, Moha; Schols, Dominique; Snoeck, Robert; Andrei, Graciela; Engels, Joachim W.; Lazrek, Hassan B.

The antiviral activity was expressed as the EC 50 : the compound concentration required to reduce virus-induced cytopathogenicity or viral plaque formation by 50%. The cytotoxicity of the tested compounds toward the uninfected host cells was defined as the minimum cytotoxic concentration (MCC) that causes a microscopically detectable alteration of normal cell morphology. The 50% cytotoxic concentration (CC 50 ), causing a 50% decrease in cell viability was determined using a colorimetric 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay system. The tested compounds (4a-j, 5a-j) displayed no antiviral activity against the different viruses tested except for compounds 4b and 4c that showed a slight inhibition of respiratory syncytial virus replication ( Table 2 ) and compounds 5c, 5f, and 5g that displayed weak activity against both TK þ and TK À VZV strains (see Supporting Information). Although compound 4h had some activity against Coxsackie virus B4 in Vero cell cultures, no activity was seen in HeLa cells (Tables 2 and 3 ).