Dietary Polysaccharides and Immune Modulation

Abstract

Polysaccharides from fungi and plants are of great economic and clinical interest and exhibit a wide variety of biological activities. They have emerged as an important class of bioactive natural products with nutraceutical and chemopreventive properties and are relatively nontoxic. The activity of polysaccharides is determined by their conformation, composition, and size. Among polysaccharides with higher biological activity, β-glucans are the most important, and they vary in conformational complexity, molecular weight, and number of branches. These characteristics can alter the biochemical and solubility properties and also influence their biological properties, such as immunomodulation and antitumor activities; metastasis inhibition; increased host resistance to bacterial, viral, parasitic, and some microbial infections; and have antimutagenic, antiallergic, regenerative, antithrombogenic, anticoagulative, antioxidant, hypolipidemic, radioprotective, and antidiabetic effects. This chapter summarizes the immune mechanisms, biological properties, pharmacokinetics, and toxicity of dietary polysaccharides primarily from fungi.