New anti-infective and neurotrophic terpenoids from cultures and "fruiting bodies*" of African, Asian and European Basidiomycota

The phylum Basidiomycota comprises the mushroom-forming fungi and various other organisms that represent a considerable part of the global biodiversity. Many new species and even genera are being recognized from modern polythetic taxonomic studies. However, most of these organisms are unfortunately not being cultured and studied for potential beneficial traits such as the production of antibiotics and other useful secondary metabolites.

During the course or our search for new anti-infective agents from nature to combat the newly arising multi-resistant human pathogens, we have started to study rare and hitherto untapped species of Basidiomycota systematically. This approach has resulted in a rather high discovery rate of novel metabolites, including several unprecedented carbon scaffolds. It is based on a combination of extensive fieldwork and classical mycological expertise together with sophisticated methods of analytical chemistry and biotechnological process development.

Basidiomycota are particularly diverse producers of terpenoids and meroterpenoids, of which we have discovered several dozens in the past years, mainly from rare and new tropical species that originate from Kenya and other African countries, or from Thailand.  Of particular interest are’: i) the complex meroterpenoids resembling hyperforin from the African grass-associated polypores of the genus Amylosporus; ii) the meroterpenoids from Echinochaete spp., which are probably produced by endofungal bacterial symbionts; iii) the unique calamene type bisheimiomycins from a Kenyan Heimiomyces sp. that also produces numerous other novel natural products; and iv) the neurotrophic cyathane, drimane, isoindolinone and benzofuranone and lanostane derivatives from the genera Antrodia, Dentipellis, Hericium, Laetiporus and others. Our results show that even European species of Basidiomycota, which are also being included in our workflow, can still yield very interesting secondary metabolites. I hope this talk can stimulate further research on the secondary metabolism of neotropical Basidiomycota as well, since the species of that geographic area remain widely unstudied.