title: Characterization of anticholinesterase-active 3-alkylpyridinium polymers from the marine sponge Reniera sarai in aqueous solutions.
abstract: From the marine sponge Reniera sarai 3-alkylpyridinium oligomers and polymers have been isolated. 3-Alkylpyridinium polymers are potent anticholinesterase agents; in addition, they show hemolytic and cytotoxic activities. Oligomers with a molecular weight lower than 3000 Da do not possess any significant activity. We report structural characterization of 3-alkylpyridinium polymers and their behavior in aqueous solutions. We found that biologically active polymers are composed of head-to-tail 3-alkylpyridinium units. According to MALDI-TOF spectrometry two species of polymers exist, the smaller with a molecular weight of 5520 Da and the larger with a molecular weight of 18,900 Da. Both polymers are soluble only in water, while low molecular oligomers are readily soluble in organic solvents. Polymers form large water-dissolved supramolecular structures with an average hydrodynamic radius of 23 +/- 2 nm and, therefore, cannot be separated with size-exclusion chromatography.
authors.affiliation: Department of Biology, Biotechnical Faculty, University of Ljubljana, Slovenia.
authors.forename: K
authors.initials: K
authors.lastname: Sepcić
authors.forename: G
authors.initials: G
authors.lastname: Guella
authors.forename: I
authors.initials: I
authors.lastname: Mancini
authors.forename: F
authors.initials: F
authors.lastname: Pietra
authors.forename: M D
authors.initials: MD
authors.lastname: Serra
authors.forename: G
authors.initials: G
authors.lastname: Menestrina
authors.forename: K
authors.initials: K
authors.lastname: Tubbs
authors.forename: P
authors.initials: P
authors.lastname: Macek
authors.forename: T
authors.initials: T
authors.lastname: Turk
mesh_terms: D000818:Animals; D002800:Cholinesterase Inhibitors / Q000302:isolation & purification / Q000494:pharmacology*; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D008027:Light; D008970:Molecular Weight; D011161:Porifera / Q000737:chemistry*; D011726:Pyridinium Compounds / Q000302:isolation & purification / Q000494:pharmacology*; D012542:Scattering, Radiation; D012996:Solutions; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013056:Spectrophotometry, Ultraviolet; D014462:Ultrafiltration
chemical_list: D002800:Cholinesterase Inhibitors; D011726:Pyridinium Compounds; D012996:Solutions