Microbial polysaccharides and their derivatives as current and prospective pharmaceuticals.

The ability to produce polysaccharides is widely found among microbial species. The structural diversity of the microbial polysaccharides (MPS) leads to a wide diversity of their applications. This review focuses pharmacological properties of MPS and their derivatives. They have been reported to possess many biological activities, such as antiviral, antitumor, antimicrobial and anticoagulant activities. So, the MPS of the type beta-1,3-D-glucans, including curdlan and scleroglucan, show antitumor and antiviral activity. A number of biological and synthetic sulfated polysaccharides, including sulfated polysaccharides from marine microalgae, inhibit viral infections. Many of MPS demonstrate a series of attractive properties as carrier materials in drug delivery systems and nonviral gene delivery. Furthermore, MPS have found an application as wound-healing agents, blood plasma expanders and vaccines. Some MPS, like chitin, chitosan and alginate have an unusual combination of biological activities and physicochemical properties leading to the development of novel or improved pharmaceuticals. They have become of a great interest not only as drug and cell carriers but also as new functional materials of high biological activity, and recent progress in MPS chemistry is quite noteworthy. This review also examines the advances in the application of MPS in the field of tissue engineering.