Varieties of Mushrooms and their Nutraceutical Importance: A Systematic Review

Abstract

Introduction: Around 2000 species of mushrooms exist in nature, of which hardly 25 varieties are accepted as edible in nature. “Nutraceuticals” are food substances that are associated with immense health benefits and also hinder the development of several maladies. Aim: This review article aims to explore the nutritional contents/composition of the varied types of mushrooms and their clinical importance for the human being. Materials and Methods: The methodology adopted is a comprehensive systematic literature review. The suitable electronic databases sources that were reviewed were Google Scholar, PubMed, PsycINFO, Medline, and Grey literature databases namely GreyNet International, Open Grey, and Med Nar. The literatures were screened by customising the databases based on the pre-determined inclusion and exclusion criteria and up to the most recent contents of the year, 2019. In total, 63 articles were considered for the systematic literature review. Results: The findings of the selected pieces of evidence were critically appraised and thematically presented. Mushrooms serve as a great nutritional source; as they are rich in proteins, contain essential amino acids, fibre, and an excellent source of fatty acids but poor in fat content. Their nutritional significance increases due to the presence of vitamins B1, B2, B12, C, D, and E. Significant content of carbohydrates are present in an edible variety of mushrooms. Trehalose, glucose, and mannitol are among the abundant sugars present in the cultivated edible mushrooms that are responsible for different categories of medicinal properties for instance immunomodulating properties, antitumour properties by modulating the immune response of the host. The distinguished protein substances present in mushrooms are specific immunomodulatory proteins, lectins, antimicrobial proteins, ribosome-inactivating proteins, ribonucleases, and laccases that have interesting biological activities. Mushrooms contain significant amounts of polyunsaturated fatty acid that contribute to the reduction of cholesterol levels in the serum and also certain essential fatty acids such as oleic acid, linolenic acid, arachidonic acid, palmitic acids. Conclusion: Mushrooms can thus be considered to be a reservoir of varied significant dietary composition contributing to a healthy diet and their daily consumption may hinder any development of maladies within our physiological system.