Ustiloxin: a phytotoxin and a mycotoxin from false smuth balls on rice panicles

Koiso, Yukiko; Natori, Mika; Iwasaki, Shigeo; Sato, Sadao; Sonoda, R. M.; Fujita, Yoshikatsu; Yaegashi, Hiroshi; Sato, Zenji

doi:10.1016/s0040-4039(00)74677-6

Cited by 118 publications

(76 citation statements)

References 7 publications

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“…Ustiloxins D (4) and F (5) have no sulfinyl appendage on the aromatic ring; they are differentiated from each other only by the presence of valine or alanine in the macrocycle. A major difference between the phomopsins 12 and the ustiloxins 16 is that, although both have a hydroxyl substituent at C-10, they are of opposite configurations.…”

Section: Ustiloxinsmentioning

confidence: 99%

“…The conditions for ether formation had to be mild to tolerate all the functionalities of these substrates and not affect any existing chiral centers. Furthermore, as the main difference between the macrocyclic core structures of ustiloxins and phomopsins 12,16 is the stereochemistry of the C-10 hydroxyl group of the β-hydroxytyrosine moiety, adoption of a single method to access all the diastereomers of N-methyl-β-hydroxytyrosine was preferred as it would be easily modifiable for the synthesis of phomopsin natural products.…”

Section: Atropisomerismmentioning

confidence: 99%

“…Comparison of the ustiloxin and phomopsin 12,16 core structures shows that the configuration of the C-10 hydroxyl group is not critical for tubulin binding, because the two natural products have opposite configurations at C-10. This observation suggested that the C-10 hydroxyl group may not play a role in the interaction of these peptides with tubulin.…”

Section: Syntheses Of (9r 10s)-epi-ustiloxin Analoguesmentioning

confidence: 99%

“…), which were isolated from the water extracts of false smut balls, caused by the parasitic fungus Ustilaginoidea virens, found on the panicles of the rice plant. [14][15][16] Ustiloxins are structurally similar to phomopsin A, and their structures were elucidated by amino acid analyses, X-ray analysis of ustiloxin A 16 and other spectroscopic data. Ustiloxins cause mycotoxicosis and inhibit the polymerization of brain tubulin at micromolar concentrations but have no growth inhibitory effect on bacteria or fungi.…”

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confidence: 99%

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Evolution of the Total Syntheses of Ustiloxin Natural Products and Their Analogues

Evans

et al. 2008

J. Am. Chem. Soc.

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Ustiloxins A-F are antimitotic heterodetic cyclopeptides containing a 13-membered cyclic core structure with a synthetically challenging chiral tertiary alkyl-aryl ether linkage. The first total synthesis of ustiloxin D was achieved in 31 linear steps using an S N Ar reaction. An nOe study of this synthetic product showed that ustiloxin D existed as a single atropisomer. Subsequently, highly concise and convergent syntheses of ustiloxins D and F were developed by utilizing a newly discovered ethynyl aziridine ring-opening reaction in a longest linear sequence of 15 steps. The approach was further optimized to achieve a better macrolactamization strategy. Ustiloxins D, F and eight analogues (14-MeO-ustiloxin D, four analogues with different amino acid residues at the C-6 position, and three (9R, 10S)-epi-ustiloxin analogues) were prepared via the second generation route. Evaluation of these compounds as inhibitors of tubulin polymerization demonstrated that variation at the C-6 position is tolerated to a certain extent. In contrast, the S configuration of the C-9 methylamino group and a free phenolic hydroxyl group are essential for inhibition of tubulin polymerization. Antimitotic agentsAntimitotic agents have long been of interest to scientists and physicians, even before their precise mechanism of action could be articulated. Most of these compounds interfere with microtubule assembly and functions thus resulting in mitotic arrest of eukaryotic cells. There are a number of natural and synthetic compounds that interfere with tubulin function to inhibit the formation of microtubules. 1 Such antimitotic agents exhibit a broad range of biological activities and can be used for medicinal and agrochemical purposes, acting as anticancer, antifungal, or anthelmintic agents. Moreover, tubulin binding compounds are valuable for understanding basic mechanisms involved in the dynamics of the microtubule network. 2 Mitotic arrest is of importance in cancer chemotherapy, since tubulin is an established chemotherapeutic target. In addition to the widely used vinca alkaloids and taxoids, many other antimitotic agents are currently in clinical or preclinical development. 3 Newer potential targets NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author Manuscript that may cause mitotic arrest are in development as well. Although cancer chemotherapy is a very important goal being extensively investigated, the mechanism of action of the naturally occurring peptides that inhibit tubulin polymerization remains a challenging problem. Attempts to establish a relationship among the tubulin binding peptides have only had limited success. [4][5][6][7][8] As a result, the mechanism of action of peptidic antimitotic agents is not completely elucidated and deserves further investigation. UstiloxinsThe first peptide shown to interact with tubulin was phomopsin A (Error! Reference source not found.). [9][10][11][12][13] Since then, a number of peptides and depsipeptides were found to disrupt cellular microtubules. These compo...

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Section: Ustiloxinsmentioning

confidence: 99%

Section: Atropisomerismmentioning

confidence: 99%

Section: Syntheses Of (9r 10s)-epi-ustiloxin Analoguesmentioning

confidence: 99%

mentioning

confidence: 99%

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Evolution of the Total Syntheses of Ustiloxin Natural Products and Their Analogues

Evans

et al. 2008

J. Am. Chem. Soc.

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“…Suwa [7] first reported the toxicity to rabbits of the water extract from such false smut balls and Koiso et al [1,2] isolated tetrapeptide substances called ustiloxins (ustiloxin A-E; Fig. 1) from the water extract of the balls.…”

mentioning

confidence: 99%

High-Performance Liquid Chromatographic Determination of Ustiloxin A in Forage Rice Silage

Miyazaki

Matsumoto

Uchihara

et al. 2009

The Journal of Veterinary Medical Science

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ABSTRACT. We describe a high-performance liquid chromatographic method for determining ustiloxin A, a mycotoxin produced by Ustilaginoidea virens, in forage rice silage. Lyophilized silage samples were ground and extracted with water. The extracts were purified by solid-phase extraction and subjected to high-performance liquid chromatography using an octadecylsilane-bonded column. Separated ustiloxin A was detected with ultraviolet (UV) absorption at 254 nm. The limit of quantitation for ustiloxin A in silage found to be 2.5 mg/kg. The present method can be used for routine monitoring of the contamination of ustiloxin A in forage rice silage. KEY WORDS: Forage Rice, HPLC, Silage, Ustiloxin A.

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