Antineoplastic agents. 556. Isolation and structure of Coprinastatin 1 from Coprinus cinereus.

Cancer cell line bioassay-guided separation of an ethyl acetate extract prepared from a plant-associated fungus, Coprinus cinereus, led to the isolation of three new sesquiterpenes, coprinastatin 1 (1), coprinol (2), and the epimer (4a), of the known sesquiterpene triol (4b). The previously described sesquiterpene 3 and oxazolinone 5 were also isolated. The structure and relative configuration of coprinastatin 1 (1) were determined by HRMS and by 1D- and 2D-NMR spectroscopic analyses. The structure of terpene 2 was elucidated by single-crystal X-ray diffraction experiments. The remaining structures were similarly determined, structure 3 by spectroscopic analyses and both 4a and 5 by X-ray crystal structure determination. Coprinastatin 1 (1) was found to inhibit growth of the murine P388 lymphocytic leukemia cell line and the pathogenic bacterium Neisseria gonorrhoeae.

Isolation of human cancer cell growth inhibitory, antimicrobial lateritin from a mixed fungal culture.

The purpose of this study was to attempt the reproducible coculture of more than two fungi for biosynthesis of potential antineoplastic substances. Five different fungi were simultaneously inoculated into broth cultures and grown for two weeks. Cancer cell line bioassay-guided fractionation, NMR, and mass spectroscopy led to the isolation and characterization of lateritin. Lateritin inhibited the growth of a mini-panel of human cancer cell lines, gram-positive bacteria, and Candida albicans. Individually, the five fungi did not synthesize detectable levels of lateritin. This study adds to the small but growing body of evidence that mixed fermentation is a viable avenue for natural product drug discovery. In addition, this is the first report of the reproducible coculture of more than two microbes for natural product biosynthesis, and the first report of the human solid tumor cell line and antimicrobial activities of lateritin.

Antineoplastic agents. 560. Isolation and structure of kitastatin 1 from an Alaskan Kitasatospora sp.

By utilizing a bioassay-guided separation (P388 lymphocytic leukemia and a panel of human cancer cell lines) of fermentation broths from a Kitasatospora sp. collected from a tundra soil sample taken at the shore of the Beaufort Sea, we have isolated three powerful (GI50 to 0.0006 microg/mL) cancer cell growth inhibitors (1-3) and determined their structures to be closely related cyclodepsipeptides. From 380 L fermentations of Kitasatospora sp. were obtained 2.6 mg of a new cyclodepsipeptide designated kitastatin 1 (3), accompanied by the previously known respirantin (1, 10.8 mg) and its valeryl homologue (2, 4.8 mg). The structures were determined by employment of a series of high-resolution mass and 2D NMR spectroscopic analyses. The stereochemical assignments and overall structures were confirmed by subsequent total synthesis of depsipeptide 1, as reported in the accompanying contribution.

Antineoplastic Agents. 554. The manitoba bacterium Streptomyces sp.

A Streptomyces sp. isolated from riverbank soil in Manitoba, Canada, was found to contain two cancer cell growth inhibitories: diazaanthraquinone 1 and 3-(hydroxyacetyl)indole (8). The structures were determined by interpretation of data from HRMS, UV, and high-field (400 MHz) NMR experiments. The red-colored diazaanthraquinone 1 and 3-(hydroxyacetyl)indole (8) were found to inhibit (0.1-3 microg/mL) growth of a minipanel of human cancer cell lines and P388 lymphocytic leukemia cells. Diazaanthraquinone 1 was also found to inhibit growth of the bacteria Streptococcus pneumoniae and Neisseria gonorrheae. However, three companion constituents, cyclo-Pro-Leu (5), cyclo-Pro-Phe (6), and cyclo-Pro-Val (7), did not inhibit cancer cell growth.