Bioactive sesquiterpenes produced by fungi: are they useful for humans as well?

Higher fungi are characterised by the production of macroscopic fruiting bodies to generate and to distribute their spores. These fruiting bodies are under constant threat of other organisms feeding on them. As a consequence these organisms developed a number of strategies for protection, one of them is the production of toxins. The fungal subdivision Basidiomycotina produce toxic sesquiterpenes many of them are derived from the protoilludane skeleton. This skeleton is transformed and rearranged to a large number of compounds. Some of these sesquiterpenes show interesting biological properties which may be attractive for medicinal chemistry. The overview describes the different types of bioactive fungal sesquiterpenes derived from humulene known to date in Basidiomycotina and their formation. The metabolites are discussed according to their sesquiterpene skeleton and the different metabolites are compared. Where available biological activities concerning antifungal, antibacterial, cytotoxic and enzyme inhibition data are given. Special attention was paid for the different activities of these metabolites and the attempts made to use them in medicinal chemistry. The question whether metabolites produced for the self-protection of fungi can be used for pharmaceutical applications for humans will be addressed and discussed.