Biomedical subjects
Publications and source records attributed to H Anke.
1(10),4-Germacradiene-2,6,12-triol (1), a new germacrane sesquiterpene, and 1,6-farnesadiene-3,10,11-triol (2), a known nerolidol derivative, were isolated from submerged cultures of the basidiomycete Resupinatus leightonii. Both compounds inhibited cAMP-induced appressorium formation in Magnaporthe grisea and showed cytotoxic activity. The structure of 1 was determined by NMR and mass spectroscopic methods.
Besides the antifungal agents variotin (1), wasabidienone B(0) (4), and phomaligin A (5), two new but inactive metabolites, viriditin (2) and O-methylviriditin (3), were isolated from extracts of the culture filtrate of liquid cultures of a strain of Aspergillus viridi-nutans. In addition, wasabidienone B(1) (6) was isolated and characterized by spectroscopy.
Six new dimeric anthraquinone derivatives, neobulgarones A (3a), B (3b), C (4a), D (4b), E (5a) and F (5b), were isolated from the mycelia of the ascomycete Neobulgaria pura together with the monomeric carviolin (1) and 1-O-methylemodin (2). All new compounds inhibited the formation of appressoria in germinating conidia of Magnaporthe grisea on inductive (hydrophobic) surface. The compounds exhibited moderate cytotoxic, but no antifungal, antibacterial, or phytotoxic activities.
Trichoflectin (1), a new azaphilone belonging to the deflectin series, 6-deoxy-7-0-demethyl-3,4-anhydrofusarubin (2), and 6-deoxy-3,4-anhydrofusarubin (3) were isolated from submerged cultures of the ascomycete Trichopezizella nidulus. All compounds showed antimicrobial activity and inhibited dihydroxynaphthalene melanin biosynthesis in fungi. The structure of trichoflectin (1) was elucidated by spectroscopic methods.
Cladobotrin (1) and rubrobramide (2) were isolated from the culture filtrate of Cladobotryum rubrobrunnescens, a mycophilic deuteriomycete. Rubrobramide (2), possessing a unique oxidized tricyclic system, is a new compound structurally related to flavipucine (3), which also is produced by the fungus. The structure of 2 was determined by spectroscopic methods. Cladobotrin (1) exhibited weak nematicidal activity toward Meldogyne incognita, while 2 showed weak cytotoxic and phytotoxic activities.
Glisoprenins C, D, and E, new glisoprenin derivatives, were isolated together with glisoprenin A from submerged cultures of the deuteromycete Gliocladium roseum HA190-95. All glisoprenins inhibited appressorium formation in Magnaporthe grisea on inductive (hydrophobic) surfaces. The compounds exhibited moderate cytotoxic, but no antifungal, antibacterial or phytotoxic activities.
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From submerged cultures of Scytalidium sp. 36-93, ten metabolites were isolated due to their effects on dihydroxynaphthalene (DHN) or DOPA melanin biosynthesis. Four of the compounds, scytalols A (1a), B (1b), C (2) and D (3), are new secondary metabolites, the structures of which were determined by spectroscopy, while the other compounds are known. Scytalols A (1a) and D (3) are selective inhibitors of DHN melanin biosynthesis and exhibit no antifungal or cytotoxic activities. Nectriapyrone, 6-methoxymellein and 4-chloro-6-methoxymellein stimulated the formation of DOPA melanin in B16-F1 melanoma cells in the absence of melanin-stimulating hormone.
The metabolism of pyrene by Penicillium glabrum strain TW 9424, a strain isolated from a site contaminated with polycyclic aromatic hydrocarbons (PAHs) was investigated in submerged cultures. The metabolites formed were identified as 1-hydroxypyrene, 1,6- and 1, 8-dihydroxypyrene, 1,6- and 1,8-pyrenequinone, and 1-pyrenyl sulfate. In addition, two new metabolites were isolated and identified by UV, 1H nuclear magnetic resonance, and mass spectroscopy as 1-methoxypyrene and 1,6-dimethoxypyrene. Experiments with [methyl-3H]S-adenosyl-l-methionine (SAM) revealed that SAM is the coenzyme that provides the methyl group for the methyltransferase involved. To our knowledge, this is the first time that methoxylated metabolites of PAHs have been isolated from fungal cultures.
The resolution of synthetic (+/-)-isovelleral (1), via chromatographic separation of the two diastereomers of the (-)-menthoxyacetic acid diester of the corresponding (+/-)-diol (3), yielded both enantiomers of the bioactive fungal metabolite (+)-isovelleral (1). While the antimicrobial and cytotoxic activities of the two enantiomers are comparable, natural (+)-1 is approximately 10 times more mutagenic towards Ames' tester strain TA98 than (-)-1. The two enantiomers of the cyclopropane ring isomer 2 also possess negligible mutagenicity compared to (+)-1. Both (+)-1 and (-)-1 have the same affinity for the vanilloid receptor, but significant different affinity for the dopamine D1 receptor.
A novel metabolite, benesudon, possessing antibacterial, antifungal, cytotoxic and phytotoxic activities, was isolated from submerged cultures of the ascomycete Mollisia benesuada. Benesudon contains a reactive alpha-methyleneketone moiety which is believed to be responsible for its antibiotic activities, it reacts with cysteine and the reaction products are devoid of biological activities. Benesudon is the first secondary metabolite described from Mollisia benesuada, and its structure was determined by spectroscopic techniques.
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The metabolism of monohalophenols by Penicillium simplicissimum SK9117, isolated from a sewage plant was investigated. In submerged cultures, 3-, 4-chlorophenol, and 4-bromophenol were metabolized in the presence of phenol. 3-Chlorophenol was transformed to chlorohydroquinone, 4-chlorocatechol, 4-chloro-1,2,3-trihydroxybenzene, and 5-chloro-1,2,3-trihydroxybenzene. With 4-chlorophenol only 4-chlorocatechol was observed as transient product. A release of chloride ions was not observed. Whereas monobromo-, and monochlorophenols could not support growth as sole carbon and energy source, growth and release of fluoride ions were observed with monofluorophenols as substrates. In presence of phenol, the degradation of all monofluorophenols was enhanced. Substrate and cosubstrate disappeared simultaneously. 3-Fluorophenol and 4-fluorophenol were completely mineralized as shown by the equimolar release of fluoride ions.
The nematicidal 5-pentyl-2-furaldehyde and the cytotoxic sesquiterpene dermatolactone were isolated from the extracts of an Ascomycete belonging to the Dermateaceae. The furan has previously been reported from the Basidiomycete Irpex lacteus, while dermatolactone is a new compound the structure of which was determined by spectrosocpic methods.
Cibaric acid (1) and 10-hydroxy-8-decenoic acid (2) are two fatty acid derivatives that are formed in the fruit bodies of Cantharellus cibarius (chanterelle) and C. tubaeformis as a response to injury. Unlike the potent defensive sesquiterpenes formed in injured fruit bodies of the pungent Lactarius species, compounds 1 and 2 only possess very weak antimicrobial and cytotoxic activity. Compound 2 was found to be a very weak direct-acting mutagen in the Ames test (<1 revertant/microgram and plate), while cibaric acid (1) was inactive in this assay. As 1 is destroyed during cooking, there are currently no reasons for suspecting that the consumption of C. cibarius poses a risk to consumers.
Five new minor metabolites, papyracon D (6), 6-O-methylpapyracon B (9), 6-O-methylpapyracon C (10), lachnumfuran A (11) and lachnumlactone A (12a), together with the known chloromycorrhizinol A (4), have been isolated from extracts of the culture fluids of the ascomycete Lachnum papyraceum. The compounds, which structures were determined by spectroscopic methods, are structurally related to the nematicidal and antibiotic mycorrhizin A (1), which also is produced by the fungus. The nematicidal, antibiotic and cytotoxic activities of the new compounds are weaker compared to those of mycorrhizin A (1). Papyracon D (6) possesses the highest antibiotic activities while lachnumlactone A (12a) is the most nematicidal and cytotoxic.
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Antitumor, antimicrobial, and phytotoxic activities of the marine antibiotic pentabromopseudilin (1a) and related phenyl-, benzyl- and benzoyl pyrroles were compared. All activities depended strongly on the substituent pattern, with the natural compound 1a being the most active one. As judged from model reactions, a covalent bond of nucleophiles to the pyrrole system may be involved in the inhibition of macromolecular syntheses.