Mushroom-Derived Indole Alkaloids

Introduction

Mushrooms have long been recognised as a rich source of bioactive natural products, contributing nutritionally and medicinally across cultures, particularly in Asia. Earlier research identified a wide variety of secondary metabolites from mushrooms, including lectins, terpenoids, sterols, phenolics and alkaloids, some of which have been developed into agrochemicals and drugs; examples cited include strobilurins and pleuromutilin-derived antibiotics. Within this broader context, indole-containing natural products have attracted attention because the indole heterocycle is considered a privileged scaffold in drug discovery and because more than 140 indole alkaloids have been reported from mushroom sources. This review sets out to collate and discuss mushroom-derived indole alkaloids, focusing on their isolation, structural diversity and reported biological activities. For clarity of scope, the authors define “mushrooms” as higher Basidiomycota, predominantly Agaricomycetes, that form visible fruiting bodies with stem, cap and gill structures, and they intentionally exclude indoles from filamentous fungi that do not meet these criteria. The collected compounds are organised into classes including simple indoles, indoleamines/tryptophols, bisindoles, β-carbolines, pyrroloquinolines, and peptide/peptaibol families, and the review highlights both well-studied molecules and many compounds for which biological data are scarce.