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Conference: Bucharest University Faculty of Physics 2002 Meeting

Section: Polymer Physics

Title:

Antitumoral activity and conformation of polysaccharides in dilute aqueous solutions

Authors:

Livia Maria Constantinescu, C. Berlic, Cristina Miron

Affiliation:

Faculty of Physics, University of Bucharest

P.O. Box-11 Magurele, Bucharest

E-mail

Keywords:

Abstract:

Microbial Beta-1,3-D-glucans, nonionic (or neutral)polysaccharides, water-soluble, have received much attention because of their industrial use (as chemical agents, food additives, drugs and so on). For example, schizophyllan and lentinan are under extensive nvestigation for their promise as anticancer drugs and Polytran scleroglucan is being used as viscosity-enhancing and suspending agents. This situation has directed the interest toward characterization of Beta-1,3-D-glucans in dilute aqueous solution. The primary purpose of this work is to characterize the industrially important Beta-1,3-D-glucans, schizophyllan and Polytran-sleroglucan in aqueous solutions, using standard techniques in polymer solutions studies such as light scattering and viscosity. Aqueous solutions of schizophyllan, have a host-mediated antitumoral activity against tumors of mice (Sarcoma 37, Sarcoma 180 and Ehrilch carcinoma). An unusually high viscosity of aqueous schizophyllan is observed, but when sonicated, the viscosity of aqueous schizophyllan solutions could be remarkably reduced, with the chemical structure and antitumoral activity of the polymer remaining intact. Molecular weight data indeed show that native schizophyllan is fragmented to lower-molecular weight chains by sonication. The hydrodynamic characterization of schizophyllan led to the conclusion that this glucan dissolves as a rodlike triple helix in water. Fragmentation of native schizophillan by sonication does not impair the antitumoral potency of the original sample, if the molecular weights of sonicated samples in water are higher than about 2,5·10^5. The ordered structure triple helix is the primary factor for the antitumoral activity of Beta-1,3-D-glucan. Finally, a study on Polytran scleroglucan solutions deals with the question whether this glucan is identical to schizophyllan in regard to chemical structure and dilute solution behavior. Reference: 1. L.M. Constantinescu, C. Berlic, C. Miron, Analele Univ. Bucuresti (Fizica), L, 5 (2001). 2. T. El Ouriaghli, These, Strasbourg (1989).