Effects of essential oils from two Lippia species on growth of phytopathogenic fungi / Efecto de los aceites esenciales de dos especies de Lippia sobre el crecimiento de hongos fitopatógenos

Chemical characterization of the essential oils of two Lippia species by GC-MS and NMR spectroscopy revealed that limonene (84.3%) and ß-caryophyllene (6.1%) were the most abundant components in Lippia turbinata while (6S,7S,10S)-trans-davanone (99.1%) predominated in Lippia integrifolia. Antifungal activity of the essential oils was determined by headspace volatile exposure assay against the fungal phytopathogenic Sclerotinia sclerotiorum, Sclerotium rolfsii and Rhizoctonia solani. The essential oil of L. turbinata showed potent antifungal activity against the panel of fungi tested while that the oil of L. integrifolia significantly inhibited the mycelial growth of S. rolfsii and R. solani.

La caracterización química de los aceites esenciales de dos especies de Lippia por cromatografía gaseosa-espectrometría de masas (CG-EM) y espectroscopia de RMN reveló que limoneno (84,3%) y ß-cariofileno (6,1%) fueron los componentes más abundantes de Lippia turbinata mientras que (6S,7S,10S)-trans-davanona (99,1%) predominó en Lippia integrifolia. La actividad antifúngica de los aceites esenciales se determinó por el ensayo de exposición a los vapores frente a los hongos fitopatógenos Sclerotinia sclerotiorum, Sclerotium rolfsii y Rhizoctonia solani. El aceite esencial de L. turbinata mostró una potente actividad antifúngica frente al panel de hongos ensayados, mientras que el aceite de L. integrifolia inhibió significativamente el crecimiento micelial de S. rolfsii y R. solani.

Constituents of Flourensia blakeana (Asteraceae).

Chemical study of the aerial parts of Flourensia blakeana Dillon allowed the isolation and identification of two novel compounds, 3, 5, 5'-trihydroxy-7, 3'- dimethoxyflavanone (1), and 2α-angeloyloxycostic acid (2) together with several known compounds. The structures were elucidated using spectroscopic data from.ID, 2D NMR and HRDEIMS experiments.

6-Methoxyflavonoids and Other Constituents from Microliabum polymnioides (Asteraceae).

The flower heads of Microliabum polymnioides afforded scopoletin, 5,4'-dihydroxy-3,6,7-trimethoxyflavone, 3,5,4'-trihydroxy-6,7-dimethoxyflavone and 3,5,7,4'-tetrahydroxy-6-methoxyflavone. The leaves contained hexadecanoic acid, phytol and docosane. This is the first report on the presence of 6-methoxyflavonoids in Microliabum genus.

Chemical composition, antifungal and herbicidal effects of essential oil isolated from Chersodoma Argentina (Asteraceae).

Analysis of the hydrodistilled essential oil of the aerial parts of Chersodoma argentina Cabrera by GC-MS and NMR spectroscopy revealed that over 80% consisted of monoterpene hydrocarbons such as alpha-thujene, alpha-pinene and beta-pinene. Contact and headspace volatile exposure assays of the essential oil demonstrated antifungal activity against Sclerotinia sclerotiorum, Sclerotium rolfsii and Rhizoctonia solani with the contact assay showing greater activity than the headspace assay. Herbicidal activity was shown by reduced root growth of Allium porrum, Solanum lycopersicon and Sorghum halepense in both assays.

Flavonoids from Pterocaulon alopecuroides with antibacterial activity.

Three flavonoids, (2 R,3 R)-5,4'-dihydroxy-3'- O-methyl-7-(gamma,gamma-dimethylallyloxy)dihydroflavonol 1, (2 R,3 R)-5,7,4'-trihydroxy-3'- O-methyl-6-(alpha,alpha-dimethylallyl)dihydroflavonol 2, and (2 R,3 R)-5,7,4'-trihydroxy-6-(alpha,alpha-dimethylallyl)dihydroflavonol 3, together with three known flavonoids ( 4 - 6), were isolated from the aerial parts of PTEROCAULON ALOPECUROIDES. The structures of the compounds were determined by mass and by 1 D and 2 D NMR spectroscopy. Screening of the antibacterial activity of all six compounds was conducted by a disc diffusion test against BACILLUS CEREUS, BACILLUS SUBTILIS, SALMONELLA TYPHIMURIUM and PROTEUS MIRABILIS. The minimum inhibitory concentration (MIC) of the active compounds ( 2, 3, 4, 6) was determined by a microdilution assay. These compounds were active only against both Gram+ bacteria with MIC values < or = 200 microg/mL.