PREPARATION AND ANTI-HIV ACTIVITY OF LOW-MOLECULAR-WEIGHT CARRAGEENANS AND THEIR SULFATED DERIVATIVES

Lambda-, kappa-, and iota-carrageenan were depolymerized in the presen ce of ferrous ions or ferrous ions plus ascorbic acid at room temperat ure. Tetrabutylammonium salts of lambda-, kappa- and iota-carrageenan were dissolved in N,N-dimethylformamide and sulfated by the addition o f pyridine-sulfur trioxide in N,N-dimethylformamide. Then, the sulfate d carrageenans were depolymerized by the incubation with ferrous ions and ascorbic acid. The anti-HIV activities of the various preparations were determined in a system in which MT-4 cells were infected with HT LV-IIIB. The activity of lambda-carrageenan was similar to that of dex tran sulfate and the depolymerized lambda-carrageenan retained high ac tivity. The activities of kappa- and iota-carrageenan and their depoly merized forms were about 6% of that of lambda-carrageenan, The sulfati on of kappa- and iota-carrageenan increased the activities of these co mpounds to the same level as that of lambda-carrageenan. However, the sulfation of lambda-carrageenan did not affect its activity. Depolymer ized sulfated kappa- and iota-carrageenan with mean molecular weights of 50,000 (81,000-46,000) had higher anti-HIV activity than dextran su lfate and all other preparations of carrageenan tested. (C) 1997 Elsev ier Science Ltd.