Ethanol extracts of 19 Malaysian traditional vegetables (locally known as 'ulam')

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1. Zearalenone, a fungal oestrogenic compound, was subjected to microbial transformation studies. Preliminary screening with 150 fungal species showed that Gliocladium roseum was capable of metabolizing zearalenone in 80-90% yields. 2. Large-scale fermentation with G. roseum produced a 1:1 mixture of 1-(3,5-dihydroxyphenyl)-10'-hydroxy-1-undecen-6'-one and 1-(3,5-dihydroxyphenyl)-6'-hydroxy-1-undecen-10'-one. The compounds were isolated and purified at -20 degrees C, and identified using spectroscopic analysis and by comparison to products obtained from alkaline hydrolysis of zearalenone.

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Zearalenone is a natural mycotoxin produced by a number of Fusarium species, particularly F. mswm (gramiwnrm) and F. tririnrtrrm (1)(2)(3)(4). This compound has been associated with a hyperestrogenic syndrome causing serious problems when fed to many classes of livestock (6,7). The diseased animals show signs of genital disorders involving vulvovaginitis, edematous uterus, and overian atrophy (7). In addition, it was reported (5-9) that zearalenone and some of its derivatives have anabolic effects and are currently used as growth promoters. The screening of 150 microorganisms for transformation ofzearalenone showed several metabolites including a-and p-zearalenone, and 8-zearalanol. The present communication describes studies related to the bioconversion of zearalenone to zearalenone glucoside by Thamnidium elegans and M w w bainieri.Small-scale experiments with 150 fungi showed that only two cultures produced a unique metabolite that had a low Rfvalue that was obtained in considerable yields by T . eIegans (60%) and M . baineiri (30%). Large-scale fermentations with T. eleguns were carried out to obtain sufficient quantities of the metabolite for structure elucidation. The metabolite was identified as zearalenone-4-0-p-glucoside on the basis of ir, nmr, and mass spectral analysis. After this report was submitted for publication, Kamimura (10) reported the structure of zearalenone-4-0-@-glucoside produced through microbial conversion of zearalenone by a species of Rhizopus, and the spectral data supporting the structure can be found in that reference. EXPERIMENTALMelting points were determined on a Fisher-Jones hot plate apparatus and are uncorrected. Ir spectra were taken with a Perkin-Elmer 281 spectrophotometer using nujol discs. High resolution mass spectra were determined on an LKB 9000 GC mass spectrometer. Nmr were taken in CDCI, or acetone-d6 using TMS as an internal standard. 'H nmr and CL3 nmr were taken on a 300 MHz Nicolet NT-3OO-W3 spectrometer.'This material is from a

Resting cells of Saccharomyces cerevisiae (baker's yeast, type II; Sigma) were used to convert oleic acid into 10-hydroxyoctadecanoic acid with a 45% yield. Nocardia aurantia (ATCC 12674), Nocardia sp. (NRRL 5646), and Mycobacteriumfortuitum (UI 53378) all converted oleic acid into 10-oxo-octadecanoic acid with 65, 55, and 80% yields, respectively. Structures of all metabolites were suggested by 'H and 13C nuclear magnetic resonance and by infrared and mass spectrometry. Structures of isomeric hydroxystearate and oxostearate derivatives and the stereochemical purity of hydroxystearates are difficult to prove unambiguously unless authentic standard compounds are available for spectral comparison. We describe the use of the chemical Baeyer-Villiger oxidation technique with 10-oxo-octadecanoic acid followed by mass spectral analysis of neutral extracts as a simple method to confirm the position of oxo-functional groups in the structures of fatty acid ketones. We further introduce a simple method based on 'H nuclear magnetic resonance analysis of diastereomeric S-(+)-O-acetylmandelate esters of hydroxystearates as a means of ascertaining stereochemical purities of hydroxy fatty acids.

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