Structure and Biological Functions of D-Glucans and Their Applications

Glucans are natural macromolecules obtained from the cell wall of yeast and cereals or as an extracellular metabolite from filamentous fungi and bacteria. Glucans have wide commercial applications in the chemical and pharmaceutical sectors because of their biomedical and technological properties. They constitute the group of biomacromolecules with demonstrated activity in stimulating the immune system and have potential in treating human disease conditions. Such biomacromolecules display anticoagulant, antithrombotic, antioxidant, and antiinflammatory activities, and they have been effective in lowering blood cholesterol levels, in reducing the risk of cardiovascular problems, and in treating various illnesses such as cancer, diabetes, and microbial infections. The chemical and conformational structure of glucans has a close relationship with biological and biomedical activities. The biological response depends on the number of units, degree of polymerization, frequency of branching, type of connections, and chain length, which corresponds to primary structure. Furthermore, there exist a considerable number of studies that described the importance of the three-dimensional conformation of the molecule on its biological properties. In this review, we show the latest advances and citations regarding the relationship between the chemical and conformational structure of glucans on antioxidant activity, immune response, antiproliferative, and hypocholesterolemic activities, as well as in the control of obesity and other benefits in human health.