RESUMO
The hydrocarbon fraction of the liverwort Trocholejeunea sandvicensis was investigated. Four new sesquiterpene hydrocarbons including the trifaranes (-)-trifara-9,14-diene (6) and (-)-3,7-di-epi-3,7-trifara-9,14-diene (7), as well as (+)-sandvicene (8), a sesquiterpene with uncommon skeleton, and the rearranged trifarane sesquiterpene (+)-neotrifaradiene (9) were isolated and their structure elucidated. A biogenetic pathway for the four compounds is proposed, with nerolidol as their common precursor.
Assuntos
Hidrocarbonetos/química , Extratos Vegetais/análise , Plantas Medicinais/química , Sesquiterpenos/química , Sesquiterpenos/isolamento & purificação , Cromatografia Gasosa-Espectrometria de Massas , Espectroscopia de Ressonância MagnéticaRESUMO
Seven phytoalexins (1-7), including a new compound, were isolated from the peel of unripe kiwi fruit (Actinidia deliciosa cv. Golden King) that had been wounded and inoculated with Colletotrichum musae. The new phytoalexin (1) was identified as 2alpha,3beta,23-trihydroxy-12,20(30)-ursadien-28-oic acid, and named actinidic acid. Phytoalexins 2-6 are known triterpenes but have not previously been described as phytoalexins. Phytoalexin 7 is the same triterpene as the phytoalexin of nectarine fruit.
Assuntos
Frutas/química , Extratos Vegetais/química , Extratos Vegetais/isolamento & purificação , Triterpenos/química , Triterpenos/isolamento & purificação , Colletotrichum/patogenicidade , Frutas/microbiologia , Espectroscopia de Ressonância Magnética , Estrutura Molecular , Doenças das Plantas/microbiologia , Sesquiterpenos , Terpenos , FitoalexinasRESUMO
Strawberry cv. Houkouwase is resistant to infection by Colletotrichum fragariae. The formation of antifungal compounds was observed in unripe fruit which had been wounded and inoculated with conidia of C. musae. Three antifungal compounds were isolated and identified as euscaphic acid, tormentic acid and myrianthic acid. Myrianthic acid inhibited the growth of C. musae at 3 microg, and euscaphic and tormentic acids showed inhibitory effects at 100 microg. A quantitative analysis of their contents showed that the triterpenes increased in wounded fruit, and in wounded and inoculated fruit, but not in non-treated fruit. These findings indicate that unripe fruit of Houkouwase produced the triterpenes as phytoalexins. The triterpene phytoalexins seem to be involved in the resistance of strawberry to the fungus.
Assuntos
Anti-Infecciosos/química , Frutas/química , Extratos Vegetais/química , Terpenos/química , Colletotrichum/imunologia , Frutas/imunologia , Imunidade Inata , Doenças das Plantas , Extratos Vegetais/imunologia , Sesquiterpenos , FitoalexinasRESUMO
Two metabolites were obtained by microbial transformation of a furanosesquiterpene alcohol, dehydropinguisenol, using Aspergillus niger and Aspergillus cellulosae. Their structures were established as 10-oxo-lejeuneapinguisenol and lejeuneapinguisenol on the basis of their spectroscopic data. The latter compound was obtained after 4 and 9 days of incubation with A. cellulosae at 30 degrees C and 25 degrees C, respectively. Aspergillus niger produced both metabolites after 3 and 5 days incubation at 30 degrees C, respectively. A possible pathway for the formation of these compounds is discussed here together with their antimicrobial activity against A. niger and A. cellulosae.
Assuntos
Aspergillus/metabolismo , Sesquiterpenos/metabolismo , Aspergillus niger/metabolismo , Biotransformação , Cinética , Magnoliopsida , Estrutura Molecular , Sesquiterpenos/químicaRESUMO
Four pinguisane type sesquiterpenes were isolated from the liverwort Trocholejeunea scandvicensis, together with three aromatic compounds. The structures of the cited compounds were established on the basis of spectroscopic means. The first two compounds were new sesquiterpenes, while the other compounds were previously isolated from other liverworts and lichen sp., respectively. The stereochemistry for lejeuneapinguisanolide was determined by X-ray analysis, a possible biosynthetic pathway to it was postulated. The other new sesquiterpene is lejeuneapinguisenone.
Assuntos
Plantas Medicinais/química , Sesquiterpenos/química , Modelos Moleculares , Conformação Molecular , Estrutura Molecular , Extratos Vegetais/química , Sesquiterpenos/isolamento & purificaçãoRESUMO
A new phytoalexin was induced and isolated from papaya fruit slices treated with copper salts; its structure was established as 3',5'-dimethoxy-4'-hydroxy-(2-hydroxy)acetophenone. This compound showed high antifungal activity against Colletotrichum gloesporioides, a pathogenic fungus of papaya.