Functional perspective of black fungi (Auricularia auricula): Major bioactive components, health benefits and potential mechanisms

Black fungi (Auricularia auricula) was known as one of the major mushrooms grown and cultivated all over the world, especially northeast Asia. It has been proved that black fungi had tremendous biological functions, and thus was being remarked to be a potential ingredient for the functional food. This review comprises a comprehensive research for the isolation and characterization of bioactive components in black fungi and their potent physiological activities. Meanwhile, chemical and metabolic methodologies are introduced to clarify the specified mechanism and future challenges. Integrated research results showed that black fungi contain some bioactive components such as polysaccharide, melanin and phenolic. According to origin and isolation method, the structural features of polysaccharide and melanin were significantly different. Health benefits such as antioxidant, hypoglycemic, antitumor and immunostimulation could be exerted with black fungi components and their derivatives. Besides, biological activity and physicochemical property of black fungi enabled the application in the drug delivery and food production. Detailed mechanisms confirmed that oxidative damage removal, immune signal transduction and gut microbiota enhancement supports the promising functionality. However, present research of black fungi still demands the more efficient extraction and purification including subcritical water, ohmic, high hydrostatic pressure (HHP) and two-phase partitioning. Challenges to some health benefits such as gut microbiota-immune, dosage suitable for clinical practice and especially structure-function relationship should also be worthwhile to increase the total functional value of black fungi.