Screening strategies for obtaining novel, biologically active, fungal secondary metabolites from marine habitats

Abstract

To determine the best sources of novel, biologically active metabolites, both endophytic fungi (plant isolates) and fungi associated with algae were isolated from plants and algae from marine habitats of the North, Baltic and Mediterranean Seas, Atlantic Ocean, and Gulf of Mexico. Following preselection of the isolates according to taxon and metabolic profiles, almost all were active in at least one of the tests for antibacterial, antifungal, and/or herbicidal activities. Metabolites isolated from the culture extracts belonged to diverse structural groups; 42% were previously unknown structures. Compared to fungi associated with algae, endophytic fungi were a better source of novel metabolites and antifungal culture extracts; they produced a higher number of metabolites per fungus. Microsphaeropsis spp. and Coniothyrium spp. synthesized the highest numbers of novel metabolites per isolate, and Geniculosporium, Nodulisporium and Phomopsis the greatest numbers of metabolites per isolate. Based on the proportion of novel to known metabolites, endophytic fungi from marine environments equalled endophytes from terrestrial habitats. Metabolic profiles (HPLC-DAD) of the saprophytic, marine fungi belonging to Dendryphiella spp. from diverse temperate and subtropical locations revealed that geographical source of the isolates had little qualitative effect on secondary metabolite production in this genus.

Diversity and biofilm inhibition activities of algicolous fungi collected from two remote islands of the Philippine archipelago

“…Fungi from marine habitats are valuable sources of biologically active secondary metabolites with potential pharmaceutical importance (Schulz et al 2008). Reports from 2013 to 2014 showed a total of 541 new compounds isolated from fungi in marine habitats (Blunt et al 2016).…”

Isofusidienols: Novel Chromone‐3‐oxepines Produced by the Endophytic Fungus Chalara sp.

“…They colonize a relatively unexplored ecological habitat and their secondary metabolism is particularly active, presumably due to metabolic interactions with their hosts. [1][2][3][4] In the course of our screening program for new fungal secondary metabolites, we investigated endophytes, which were isolated from numerous plant genera from diverse marine habitats. The endophytic fungus Chalara sp., strain 6661, was isolated following surface sterilization [4,5] from Artemisia vulgaris, collected close to Ahrenshoop, Germany, on the coast of the Baltic Sea.…”

A search for antiplasmodial metabolites among fungal endophytes of terrestrial and marine plants of southern India

“…Pharmaceutically important secondary metabolites-producing endophytes, compatible with in vitro cultures offer special advantages that include cost-effective large scale production of the metabolites in industrial laboratory settings. In this regard, endophytes from marine habitats appear to be unique since many of them produce different novel (Bugni and Ireland 2004;Jones et al 2008;Raghukumar 2008;Schulz et al 2008;Kjer et al 2010;Suryanarayanan et al 2011;Flewelling et al 2013). Nearly 30% of the novel metabolites produced by marine-derived fungi are from fungi associated with marine algae (Bugni and Ireland 2004); some of these fungi produce metabolites having hitherto unknown carbon frameworks (Kjer et al 2010) .…”