CHARACTERIZATION OF ANTICHOLINESTERASE-ACTIVE 3-ALKYLPYRIDINIUM POLYMERS FROM THE MARINE SPONGE RENIERA-SARAI IN AQUEOUS-SOLUTIONS

From the marine sponge Reniera sarai 3-alkylpyridinium oligomers and p olymers have been isolated. 3-Alkylpyridinium polymers are potent anti cholinesterase agents; in addition, they show hemolytic and cytotoxic activities. Oligomers with a molecular weight lower than 3000 Da do no t possess any significant activity. We report structural characterizat ion of 3-alkylpyridinium polymers and their behavior in aqueous soluti ons. We found that biologically active polymers are composed of head-t o-tail 3-alkylpyridinium units. According to MALDI-TOF spectrometry tw o species of polymers exist, the smaller with a molecular weight of 55 20 Da and the larger with a molecular weight of 18 900 Da. Both polyme rs are soluble only in water, while low molecular oligomers are readil y soluble in organic solvents. Polymers form large water-dissolved sup ramolecular structures with an average hydrodynamic radius of 23 +/- 2 nm and, therefore, cannot be separated with size-exclusion chromatogr aphy.