The isolation, bioactivity, and role of β-glucans in health: A review

β-glucans are bioactive polysaccharides with promising health benefits. These compounds are naturally present in plant-based sources, such as barley and oats, and microorganism sources, including bacteria, fungi, and yeast. They are acidic polymers composed of glucose monomers connected by β-glycosidic bonds. Extensive research has examined their positive impact on human health. β-glucans display a broad spectrum of biological activities, including immunomodulatory, antioxidant, anticancer, and wound healing effects. The therapeutic potential of β-glucans has been explored in numerous clinical studies, supporting their growing application in the pharmaceutical, food, and cosmetic industries. However, the biological activity of β-glucans is strongly influenced by their source-specific physicochemical properties, including molecular weight, degree of branching, glycosidic linkage type, and solubility. Understanding these differences is key to optimizing their therapeutic application. In this review, we provide an updated and comprehensive analysis of the isolation methods and structural characterization of β-glucans, with a focus on how structural features influence functionality. This review highlights the principal bioactivities of β-glucans, with an emphasis on their anti-tumor, anti-inflammatory, antioxidant, immunomodulatory, and wound healing roles. Collectively, these attributes reinforce the potential of β-glucans as versatile therapeutic agents in a range of clinical and industrial applications.