Cryptocin, a potent tetramic acid antimycotic from the endophytic fungus Cryptosporiopsis cf. quercina

Organic Letters

Volumn 2, Issue 6, 2000, Pages 767-770

  Li, J Y ^a   Strobel, Gary ^a   Harper, James ^a   Lobkovsky, Emil ^b   Clardy, Jon ^b  

^a MONTANA STATE UNIVERSITY   (United States)

^b Department of Molecular Biology and Genetics   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

CRYPTOCIN; NAPHTHALENE DERIVATIVE; PYRROLE DERIVATIVE;

ARTICLE; ASCOMYCETES; CHEMICAL STRUCTURE; CHEMISTRY; CONFORMATION; DRUG EFFECT; FUNGUS; HUMAN; MICROBIOLOGICAL EXAMINATION; MICROBIOLOGY; PLANT; PLANT DISEASE; PLANT STEM;

ASCOMYCOTA; FUNGI; HUMANS; MICROBIAL SENSITIVITY TESTS; MODELS, MOLECULAR; MOLECULAR CONFORMATION; NAPHTHALENES; PLANT DISEASES; PLANT STEMS; PLANTS; PYRROLES;

EID: 0034704606     PISSN: 15237060     EISSN: None     Source Type: Journal    
DOI: 10.1021/ol000008d     Document Type: Article

References (15)

1. Strobel, G. A.; Miller, R. V.; Miller, C.-M.; Condron, M. M.; Teplow, D. B.; Microbiol. 1999, 145, 1919.
2. Walsh, T. A. Inhibitors of glucan synthesis. In Emerging Targets in Antibacterial and Antifungal Chemotherapy; Sutcliffe, J. A., Georgopapadakou, N. H., Eds.; Chapman and Hall: London, 1992; pp 349-373.
3. The first silica gel chromatography was performed on a 3 x 30 cm column. The organic solvent extract was applied to the column and eluted with 500 mL of chloroform:acetonitrilewater 10:1:0.1 v/v. The first 100 mL eluting from the column was discarded and the next 400 mL to elute from the column (possessing bioactivity) was taken to dryness (350 mg), redissolved in 2.0 mL of methanol, and placed on the second silica gel column (identical in size to the first column). It was eluted with ethyl acetate: methanol 20:10 v/v. Fractions (10 mL) were collected, and the bioactivity appeared at 150-200 mL.
4. 5 In addition, application of the compound (20 μg) to an Altima C-18 reverse phase HPLC column (7.0 x 250 mm) and separation in a linear 30-70% gradient of acetonitrile over 30 min revealed a single UV absorbing (254 nm) peak with a retention time of 14.3 min. By these criteria, the compound was considered homogeneous.
5. f values recored for each system are as follows: chloroform:acetonitrile, 3:2 v/v, 0.25; chloroform:methanol: acetic acid, 15:1:0.1 v/v, 0.51; ethyl acetate:methanol:ammonium hydroxide, 5:1:0.1 v/v, 0.47; ethyl acetate:methanol, 5:1 v/v, 0.72; chloroform:methanol, 7:1 v/v, 0.68; methylene dichloride:methanol:dimethylforamide, 9:1:0.1 v/v, 0.53; methylene dichloride:tetrahydrofuran, 6:1 v/v, 0.55; ethyl acetate:2-propanol, 95:5 v/v 0.19; ethyl acetate:tetrahydofuran, 3:1 v/v, 0.43; methylene dichloride:acetonitrile, 2:1 v/v, 0.36.
6. Cardellina, J. H. J. Chromatogr. 1991, 14, 659.
7. Supporting Information is available as tables of fractional coordinates, thermal parameters, and interatomic and torsional angles.
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14. MIC values for cryptocin were obtained using a standard plate bioassay test method that employs a microtitre plate containing various concentrations of the test compound and the fungus to be tested in PD broth. Each well, after 24 h, was visually observed, and the well showing no growth next to well having some growth was taken as the MIC concentration value. The activity of cryptocin was directly compared with that of a known antimycotic, pseudomycin A. Details of the assay methods are given in ref 1.
15. Ou, S. H. Rice Diseases; C.A.B. Kew: Surrey, England, 1972.