So far unknown tropical mushrooms source of important active substances

New agents against nematodes and germs discovered in tropical mushrooms

Penicillin is still one of the best-known antibiotics and was discovered more than one hundred years ago in mushrooms that naturally form it. Since then, fungi have been used in drug discovery as a natural source of antimicrobials. In a recent study, an international research team has now been looking for new active ingredients in previously unknown tropical mushrooms - with success!

The fungal diversity in tropical regions promises, according to the scientists a wealth of new chemical substances with antibiotic activity, but it has so far little research. The international research group headed by Prof. Marc Stadler from the Helmholtz Center for Infection Research (HZI) has now discovered new natural substances with effects against bacteria and roundworms in fungal samples from the rainforest of Thailand. The results of the scientists were published in the journal "MycoKeys".

Scientists have isolated new antimicrobial and nematicidal compounds from a previously unknown tropical fungus. (Image: Alexander Raths / fotolia.com)

Tropical mushrooms as an active ingredient supplier

Fungi play a crucial role in the search for new drugs, and their wealth of metabolic products with selective biological activity are well-suited to the development of new drugs, according to the HZI's statement. In particular, the so-called mycobiota of tropical countries have high potential here. From the mushrooms in a habitat with large, yet little developed biodiversity, remedies for a variety of ailments could be obtained. According to the researchers, in recent years many new active substances with antimicrobial, cytotoxic and antioxidant effects have already been isolated from tropical fungi.

Mushrooms from the Thai rainforest examined

Already in 2015, the international research group led by Prof. Stadler, head of the HZI department "Microbial agents" and scientists of the German Center for Infection Research (DZIF), collected fungal samples in the rainforest of Thailand, which were subsequently examined in the laboratory. For this purpose, the individual fungal strains were isolated and initially characterized by sequencing - so-called genetic barcoding. Already known genera were sorted out and the isolated strains analyzed morphologically and phylogenetically.

New fungus genus identified

Thus, the scientists came across a new species of fungus from the previously largely unknown world of fungi. This genus was noted by antagonistic reactions and from it eight natural products with antibiotic and nematicidal effects (lethal effect on nematodes or roundworms) were extracted and identified, reports the HZI. Six of these agents had previously been unknown to science. The new mushroom was named Pseudobambusicola thailandica.

Another 30 more fungus strains under investigation

Although the biological activity of the discovered substances is only moderate according to the researchers, they are not suitable for drug development. However, it is still being investigated whether the new fungus could be suitable for the biological control of pathogenic nematodes and fungi in agriculture. In addition, the project represents only a small step in the drug discovery of fungi and around 30 other fungal strains are currently being analyzed, according to Clara Chepkirui, PhD student in Prof. Stadler's team.

"We are looking for new species and genera of fungi that are suitable for use as biological pesticides or as producers of new active substances," says Professor Stadler, summarizing the goals of the EU-funded "GoMyTri" research project. The current interdisciplinary project involved young chemists, biologists and engineers from Egypt, China, Colombia, Cameroon, Croatia, Kenya, Thailand, the Philippines, the Netherlands and Germany, reports the HZI. (Fp)