Himalayan Mushrooms as a Natural Source of Ergosterol and Vitamin D2: A Review of Nutraceutical and Functional Food Perspectives

Abstract

Mushroom diversity is essential for maintaining ecological balance and provides valuable bioactive compounds for human use. Beyond their nutritional value, mushrooms contribute to functional foods and have applications in nutraceuticals, pharmaceuticals, and biotechnology. For example, β-glucans from Lentinula edodes are commercialized as immune-enhancing nutraceuticals, polysaccharide Krestin (PSK) from Trametes versicolor is used as an adjuvant in cancer therapy, and enzymes such as laccases from Pleurotus species are widely applied in biotechnological processes. One of the abundant compounds found in mushrooms is ergosterol, which is a sterol present in the cell membrane of the fungal body. Ergosterol has significant health benefits due to its antioxidant, immunomodulatory, and anti-inflammatory properties. Furthermore, ergosterol is a precursor to vitamin D₂ (ergocalciferol), which can be synthesized through exposure to ultraviolet (UV) light and thermal radiation. This review highlights the importance of Himalayan mushroom biodiversity, particularly the wild edible mushrooms traditionally collected and used. This review thoroughly discusses the ergosterol and vitamin D₂ content, their biosynthesis in mushrooms, and the role of environmental factors used to enhance biosynthesis. We also discuss the sustainable cultivation of Himalayan mushrooms and their nutraceutical properties. Several Himalayan mushrooms have been reported to possess health-promoting properties, and their incorporation into functional foods may contribute to improved public health. Furthermore, the future research directions are highlighted.