- New mycotoxins from the scale insect fungus Aschersonia coffeae Henn. BCC 28712
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Nine new mycotoxins; five xanthones 1-5, hydroxanthone 6, and three anthraquinones 7-9, together with nine known compounds; sterigmatocystin (10), demethylsterigmatocystin (11), dihydrodemethylsterigmatocystin (12), sterigmatin (13), austocystin F (14), averufin (15), aflatoxin B1, paeciloquinone A, and zeorin, were isolated from the scale insect fungus Aschersonia coffeae Henn. BCC 28712. The structures of these compounds were elucidated using NMR spectroscopic and MS spectrometric analyses. Compounds 1e3 and 6e9 displayed cytotoxic activity while the xanthone 2 and anthraquinones 8 and 9 also showed antimalarial activity.
- Kornsakulkarn, Jittra,Saepua, Siriporn,Srichomthong, Kitlada,Supothina, Sumalee,Thongpanchang, Chawanee
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experimental part
p. 8480 - 8486
(2012/10/08)
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- Evidence for the Probable Final Steps in Aflatoxin Biosynthesis
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The final steps in the biosynthesis of the potent environmental carcinogen aflatoxin B1 (8) are believed to involve the oxidative cleavage and rearrangement of O-methylsterigmatocystin (7) with loss of a C1-unit.The means by which this overall transformation occurs is not known and has been addressed using cell-free conversions of samples of radiolabeled 7 that were obtained by the incorporation of either - or acetate.The proportion of radioisotope detected in aflatoxin B1 relative to that of the C1-unit liberated (formaldehyde, formic acid, or carbon dioxide) was tested. Carbon dioxide alone was isolated in the proper stoichiometry to limit the possible mechanisms that can be acting at the conclusion of this biosynthetic pathway.
- Chatterjee, Moneesh,Townsend, Craig A.
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p. 4424 - 4429
(2007/10/02)
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