FR191512, a novel anti-influenza agent isolated from a fungus strain No.17415. I. Taxonomy, fermentation, isolation, physico-chemical properties and structure elucidation

Isolation, purification and characterization of novel antimicrobial compound 7-methoxy-2,2-dimethyl-4-octa-4',6'-dienyl-2H-napthalene-1-one from Penicillium sp. and its cytotoxicity studies

Fungus isolated from soil has been evaluated for its antimicrobial activity which showed broad spectrum antimicrobial activity against all the pathogenic microorganisms used. Optimization was done by response surface methodology (RSM) to further optimize the medium which could further enhance the antimicrobial activity by 1.1-1.9 folds. Column chromatography was used to isolate the active compound which was characterized to be by various spectroscopic techniques such NMR, IR and LCMS and it was found to be apparently novel compound 7-methoxy-2,2-dimethyl-4-octa-4',6'-dienyl-2 H -napthalene-1-one. MIC of the active compound ranged from (0.5-15 µg/mL which was found to be comparable with the standard antibiotics. Viable cell count studies of the active compound showed it to be bactericidal in nature. Further, the compound when tested for its biosafety was found neither to be cytotoxic nor mutagenic. Cytotoxicity studies of the compound on cancer cell lines showed a valuable cytotoxic potential against all tested human cancer cell lines. Further, the compound induces apoptosis in lung cancer (A549) cells reveled by increase the distribution of nuclear DNA in Sub G1 phase as observed in flow cytometry. The study demonstrated that an apparently novel compound isolated from Penicillium sp. seems to be a stable and potent antimicrobial.

Homolog separation, a necessity for the proper identification of fungal metabolites

Monitoring of fungal extracts for the production of novel metabolites, using a modular analytical system combining HPLC with UV-MS-ELS detection, identified culture LL-W1278 as a fungus producing new biopolymers. Only a non-routine HPLC analysis of a culture extract revealed that the standard water-acetonitrile elution method did not separate all members of the metabolite complex. Fine-tuning the eluting solvents established that it was essential to include acid with the water-methanol system to separate the new materials. The routinely used water-acetonitrile system, with or without acid, was incapable of separating all homologues. With the modified method the new homologues W1278-Ax, Bx, and Cx were separated. LC/MS analysis indicated that these compounds had molecular weights of 706, 900, and 1094, respectively, 44 mass units lower than their three major homologues, W1278-A, B, and C, identified previously. UV and NMR data as well as mass fragmentation patterns established unambiguously that the new compounds lacked a carboxyl group at the terminal resorcinol unit of the biopolymer, consisting of several catenated hydroxymellein residues. A time study concerning the stability of these fungal metabolites showed a slow, but complete degradation of the primary metabolites over several months when kept as a DMSO solution.

Absolute stereochemistry of unusual biopolymers from Ascomycete culture LL-W1278: examples that derivatives of (S)-6-hydroxymellein are also natural fungal metabolites

The new linear polyesters, W1278-A, B, and C, were isolated from culture extracts of a freshwater Ascomycete fungus. Their structures were elucidated on the basis of spectroscopic analyses and chemical transformations, with the absolute configuration established by the circular dichroism (CD) method using (R)-(-)-6-hydroxymellein as reference. Unexpectedly, W1278-A, B, and C contain (S)-6-hydroxymellein residues as concluded from the display of the opposite ellipticity than that of known (3R)-(-)-3,4-dihydro-6,8-dihydroxy-3-methylisocoumarin as revealed by CD.