The chemistry of the Euphorbiaceae. VII. The diterpenes of Ricinocarpus stylosus Diels

Henrick, CA; Jefferies, PR

doi:10.1071/ch9640915

Cited by 106 publications

(33 citation statements)

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“…The observed rotation for GF is [a] 25°c= +46°[CHC13], in reasonable agreement with the original value of + 32 ° (Brieskorn & Pohlman, 1969) while the rotation of KA is -102 °, close to the original report of -110 ° (Henrick & Jefferies, 1964). It is noteworthy that the opposite rotation for the two compounds does not imply that they exist as opposite enantiomers.…”

Section: Mithril Shelx76supporting

confidence: 76%

Structure of (4α)-kaura-9(11),16-dien-18-oic acid (grandiflorenic acid), an active ingredient of the Mexican medicinal plant zoapatle

Reynolds¹,

Lough²,

Sawyer³

et al. 1991

Acta Crystallogr C

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Section: Mithril Shelx76supporting

confidence: 76%

Structure of (4α)-kaura-9(11),16-dien-18-oic acid (grandiflorenic acid), an active ingredient of the Mexican medicinal plant zoapatle

Reynolds¹,

Lough²,

Sawyer³

et al. 1991

Acta Crystallogr C

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“…Kauralexin B1 is a logical precursor for kauralexin B2/B3 and is likely derived from pathogen-induced ent-kaur-15-ene (15). With the exception of kauralexin B3, these diterpenoids have been previously described in dicotyledonous plants; however, kauranes have not been previously established to function as rapidly inducible phytoalexins (20)(21)(22)(23)(24). These compounds are readily quantified by GC similar to the routine analysis of fatty acid methyl esters (25).…”

Section: Resultsmentioning

confidence: 96%

Identity, regulation, and activity of inducible diterpenoid phytoalexins in maize

Schmelz

Kaplan

Huffaker

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

235

281

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Phytoalexins constitute a broad category of pathogen-and insectinducible biochemicals that locally protect plant tissues. Because of their agronomic significance, maize and rice have been extensively investigated for their terpenoid-based defenses, which include insect-inducible monoterpene and sesquiterpene volatiles. Rice also produces a complex array of pathogen-inducible diterpenoid phytoalexins. Despite the demonstration of fungal-induced entkaur-15-ene production in maize over 30 y ago, the identity of functionally analogous maize diterpenoid phytoalexins has remained elusive. In response to stem attack by the European corn borer (Ostrinia nubilalis) and fungi, we observed the induced accumulation of six ent-kaurane-related diterpenoids, collectively termed kauralexins. Isolation and identification of the predominant Rhizopus microsporus-induced metabolites revealed ent-kaur-19-al-17-oic acid and the unique analog ent-kaur-15-en-19-al-17-oic acid, assigned as kauralexins A3 and B3, respectively. Encoding an entcopalyl diphosphate synthase, fungal-induced An2 transcript accumulation precedes highly localized kauralexin production, which can eventually exceed 100 μg·g −1 fresh weight. Pharmacological applications of jasmonic acid and ethylene also synergize the induced accumulation of kauralexins. Occurring at elevated levels in the scutella of all inbred lines examined, kauralexins appear ubiquitous in maize. At concentrations as low as 10 μg·mL −1 , kauralexin B3 significantly inhibited the growth of the opportunistic necrotroph R. microsporus and the causal agent of anthracnose stalk rot, Colletotrichum graminicola. Kauralexins also exhibited significant O. nubilalis antifeedant activity. Our work establishes the presence of diterpenoid defenses in maize and enables a more detailed analysis of their biosynthetic pathways, regulation, and crop defense function.

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“…Methyl kaurenoate 2 has been prepared by diazotization of 1 in good yields by many research groups, 9,[19][20][21] but the harmful reaction conditions and the restrictions associated with the preparation of other diazoalkanes precluded its general use. On the other hand, synthesis of 3-hydroxypropyl kaurenoate 3 was achieved 22 by treatment of kaurenoic acid 1 with triphenylphosphine in carbon tetrachloride followed by addition of 1,3-propanediol to the unstable acyl chloride intermediate (Scheme 1).…”

Section: Resultsmentioning

confidence: 99%

“…18 Oxidative cleavage 19,20 of the olefin moiety in 1 gave the keto acid 15 which was methylated with CH 3 I in KOH-acetone to afford methyl norkauranoate 16 quantitatively (Scheme 3). To carry out the antifungal evaluation, concentrations of kaurenoic acid and its derivatives up to 250 μg mL -1 were incorporated to growth media according to NCCLS guidelines.…”

Section: Resultsmentioning

confidence: 99%

A simple synthesis of kaurenoic esters and other derivatives and evaluation of their antifungal activity

Boeck

Sá

Souza

et al. 2005

J. Braz. Chem. Soc.

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Este trabalho descreve a preparação de ésteres e amidas derivados do ácido caurenóico e a avaliação da atividade antifúngica frente a cepas padronizadas de fungos patogênicos. Ésteres alquílicos e benzílicos foram obtidos com bons rendimentos, sob condições brandas, a partir da esterificação do ácido caurenóico com haletos de alquila em KOH-acetona. Todos os compostos sintetizados foram submetidos aos testes de inibição contra leveduras, hifomicetos e dermatófitos, mas somente o ácido caurenóico e os derivados contendo um grupo carboxilato livre apresentaram atividade moderada frente a dermatófitos.Representative esters derived from kaurenoic acid were prepared in order to evaluate their antifungal properties. Alkyl and substituted benzyl esters were obtained in good yield under mild conditions by esterification of kaurenoic acid with the corresponding alkyl halide in KOH-acetone. All synthesized compounds were tested for antifungal properties against pathogenic yeasts, hialohyphomycetes and dermatophytes. Kaurenoic acid and derivatives containing a free carboxyl group were moderately active against dermatophytes.

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The chemistry of the Euphorbiaceae. VII. The diterpenes of Ricinocarpus stylosus Diels

Cited by 106 publications

References 0 publications

Structure of (4α)-kaura-9(11),16-dien-18-oic acid (grandiflorenic acid), an active ingredient of the Mexican medicinal plant zoapatle

Structure of (4α)-kaura-9(11),16-dien-18-oic acid (grandiflorenic acid), an active ingredient of the Mexican medicinal plant zoapatle

Identity, regulation, and activity of inducible diterpenoid phytoalexins in maize

A simple synthesis of kaurenoic esters and other derivatives and evaluation of their antifungal activity

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