Stereoselective Reduction of Radicinin by Liquid Cultures of Alternaria longipes

Sheridan, Helen; Smyth, Ciara; Canning, Ann-Marie; James, John P.

doi:10.1021/np50085a026

Cited by 4 publications

(7 citation statements)

References 7 publications

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“…Cochliotoxin 23 [α] D −84 (c 1.0 CHCl 3 ); lit. 13 [α] D −92 (c 0.48 CHCl 3 )]; 1 H and 13 C NMR spectra were very similar to those reported in the literature; 14,23 HRESIMS (+) m/z 239.0924 [M + H] + (calcd for C 12 H 15 O 5 239.0920).…”

Section: Journal Of Natural Productssupporting

confidence: 74%

“…A new phytotoxic metabolite, named cochliotoxin ( 1 ), was isolated together with four closely related metabolites. These were identified as radicinin, , 3- epi -radicinin, radicinol, and 3- epi -radicinol , ( 2 – 5 ) by comparing their physical (OR) and spectroscopic properties ( 1 H NMR and ESIMS) with the data reported in the literature.…”

Section: Resultsmentioning

confidence: 99%

“…Cochliotoxin is closely related to the two epimeric radicinins ( 2 and 3 ) and the two epimeric radicinols ( 4 and 5 ). These metabolites are produced by different fungi such as Alternaria longipes , Bipolaris coicis , Alternaria chrysanthemi , Alternaria radicina , Curvularia sp. FH01, and Cochliobolus sp .…”

Section: Resultsmentioning

confidence: 99%

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Cochliotoxin, a Dihydropyranopyran-4,5-dione, and Its Analogues Produced by Cochliobolus australiensis Display Phytotoxic Activity against Buffelgrass (Cenchrus ciliaris)

et al. 2017

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Buffelgrass (Pennisetum ciliare or Cenchrus ciliaris) is a perennial grass that has become highly invasive in the Sonoran Desert of southern Arizona. In the search for novel control strategies against this weed, strains of the foliar fungal pathogen Cochliobolus australiensis from buffelgrass have been screened for their ability to produce phytotoxic metabolites that could potentially be used as natural herbicides in an integrated pest management strategy. A new phytotoxin, named cochliotoxin, was isolated from liquid culture of this fungus together with radicinin, radicinol, and their 3-epimers. Cochliotoxin was characterized, essentially by spectroscopic methods, as 3-hydroxy-2-methyl-7-(3-methyloxiranyl)-2,3-dihydropyrano[4,3-b]pyran-4,5-dione. Its relative stereochemistry was assigned by H NMR techniques, while the absolute configuration (2S,3S) was determined applying the advanced Mosher's method by esterification of its hydroxy group at C-3. When bioassayed in a buffelgrass coleoptile elongation test and by leaf puncture bioassay against the host weed and two nontarget grasses, cochliotoxin showed strong phytotoxicity. In the same tests, radicinin and 3-epi-radicinin also showed phytotoxic activity, while radicinol and 3-epi-radicinol were largely inactive. All five compounds were more active in leaf puncture bioassays on buffelgrass than on the nontarget grass tanglehead (Heteropogon contortus), while the nontarget grass Arizona cottontop (Digitaria californica) was more sensitive to radicinin and 3-epi-radicinin. Cochliotoxin at low concentration was significantly more active on buffelgrass than on either native grass, but the difference was small.

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Section: Journal Of Natural Productssupporting

confidence: 74%

Section: Resultsmentioning

confidence: 99%

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Cochliotoxin, a Dihydropyranopyran-4,5-dione, and Its Analogues Produced by Cochliobolus australiensis Display Phytotoxic Activity against Buffelgrass (Cenchrus ciliaris)

et al. 2017

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“…3 Based on these data and a comparison with literature values, 4 3 was identified as 3-epiradicinol, previously isolated from cultures of A. chrysanthemi and A. longipipes. 5 The third compound (4) recovered from the growth medium, with the molecular formula C 13 H 16 O 5 , was also an optically active oil. Absorbances in the IR spectrum at 3400, 1700, and 1400 cm -1 were similar to those observed in the spectra of 2 and 3.…”

mentioning

confidence: 96%

“…This is in keeping with the observation that carbon source can influence the enzymes produced by a microorganism, and this, in turn, can lead to a difference in the stereochemical course of the reduction. 5,7 As the cultures of A. chrysanthemi age, it appears that selective methylation of 3 occurs at the 3-OH group. Partial epoxidation of 4 may be catalyzed by the aging cultures to yield 5, or this isolate may be an artifact from atmospheric oxidation.…”

mentioning

confidence: 99%