| Unlike the numerous studies of terrestrial fungi, chemical studies of fungi from phylloplane, marine, and freshwater environments have been limited. Competitive and nutritional factors within these habitats differ from those of the terrestrial environment and may suggest the presence of some distinctive secondary metabolic characteristics in organisms from these habitats. Thus, fungi from phylloplane, marine and freshwater environments may produce new and unique biologically active metabolites.;Isolates of phylloplane, marine, and freshwater fungi were obtained from public and private culture collections and were grown in liquid fermentation culture. Culture extracts showing antimicrobial activity and/or brine shrimp toxicity were subjected to bioassay-directed fractionation using chromatographic techniques in efforts to isolate the compound(s) responsible for the observed bioactivity. The chemical structures of these compounds were established mainly through 1-D and 2-D NMR, MS, and chemical derivatization and degradation experiments.;From the phylloplane fungus, Alternaria brassicicola, a new acylated mannitol containing two novel racemic ;From the marine fungi, Helicascus kanaloanus, two new ;A freshwater isolate of Preussia aurantiaca was found to produce two new antimicrobial depsidones called auranticins A and B. Kirchsteinothiellia sp. (CS-76-1) was found to produce five known ethylnaphthoquinone derivatives, a new antibacterial naphthoquinone dimer (kirchsteinin), and two new antimicrobial chlorinated substituted phenyl ethers.;Thus, studies of phylloplane, marine, and freshwater species have led to the isolation of several structurally unique and biologically active secondary metabolites. These studies suggest that further chemical investigations of fungi from these environments are warranted. |
