Synthesis and Evaluation of Biological Activity of a Potential Immunomodulatory Zwitterionic Polysaccharide.

摘要

The gram-negative anaerobic bacterium Bacteroides fragilis is an integral component of the normal gastrointestinal flora. The bacterium colonizes the intestinal tract of human beings as it has no reservoir other than mammals. An unprecedented proportion of the genomic DNA of B. fragilus is involved in the production of capsular polysaccharides. These capsular polysaccharides are important virulence factors in most extracellular bacterial pathogens. Eight of these polysaccharides have been identified thus far, out of which two were found to be zwitterionic polymers, PSA1 and PSA2. PSA1 was found to stimulate T-cell lineage of the immune system because of the dual charge structural feature of the molecule.;This dissertation discusses about the synthesis of a PSA1 analogue and evaluating its immunomodulatory activity. Also discussed are the synthesis and the chemical reactivity of 3,6-anhydro-D-glucal which was formed unexpectedly in the synthesis of L-rhamnal.