STRUCTURAL INVESTIGATION AND ANTI-HIV ACTIVITIES OF HIGH-MOLECULAR-WEIGHT ATA POLYMERS

Aurintricarboxylic acid (ATA) was prepared from salicylic acid, formaldehyde, sulfuric acid, and sodium nitrite using a prolonged reaction time in order to favor the production of high molecular weight polymers. The resulting material was fractionated on the basis of molecular weight into nine fractions by equilibrium dialysis and ultrafiltration. Comparison of the NMR spectral data of these polymer fractions with the NMR spectra of low molecular weight ATA components provided a revised schematic representation of the structures of the ATA polymers used in the present study. The low molecular weight components were previously obtained from an ATA sample prepared using a limited reaction time. The anti-HIV activities of the ATA fractions were also investigated. The assays included prevention of the cytopathic effect of HIV-1 and HIV-2 in MT-4 cells, prevention of the cytopathic effect of HIV-1 in CEM cells, cytotoxicity in MT-4 cells, inhibition of syncytium formation between MOLT-4 cells and either HIV-1- or HIV-2-infected HUT-78 cells, and inhibition of HIV-1 binding to MT-4 cells. The potencies of the fractions in preventing the cytopathic effects of HIV-1 and HIV-2 increased as the average molecular weights of the fractions increased up to a dialysis molecular weight range of 7000-12 000 Da, which had weight average and number average molecular weights (M(w) and M(n)) of approximately 2937 and 2547, respectively. Further increase in the molecular weight beyond this point did not result in a further increase in potency, and the highest molecular weight fractions displayed decreased potencies for prevention of the cytopathic effects of HIV-1 and HIV-2 in MT-4 cells as well as for inhibition of syncytium formation between MOLT-4 cells and HIV-1 or HIV-2-infected HUT-78 cells.