Beta-glucans can be isolated from various sources including fungi, bacteria, and plants. They are a heterogeneous group of glucose polymers that constitute important structural or skeletal components of the cell wall. In the past half-century, many efforts have focused on the preparation process, structural analysis, and biological activity of β-glucans. Especially, lentinan as a β-glucan derived from mushroom has been used as an adjuvant in clinical cancer therapy for its immune-enhancement and anticancer activities. Besides, chemical modifications such as carboxymethylation, sulfation, and acetylation applied to prepared derivatives of β-glucans produce some special properties. In this chapter, the source, preparation and purification method, structural properties, and biological activities, as well as the bioactivity–structure relationship of β-glucan are reviewed.
