RESUMO
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 caracterizacioÌn quiÌmica de los aceites esenciales de dos especies de Lippia por cromatografiÌa gaseosa-espectrometriÌa de masas (CG-EM) y espectroscopia de RMN reveloÌ que limoneno (84,3%) y ß-cariofileno (6,1%) fueron los componentes maÌs abundantes de Lippia turbinata mientras que (6S,7S,10S)-trans-davanona (99,1%) predominoÌ en Lippia integrifolia. La actividad antifuÌngica de los aceites esenciales se determinoÌ por el ensayo de exposicioÌn a los vapores frente a los hongos fitopatoÌgenos Sclerotinia sclerotiorum, Sclerotium rolfsii y Rhizoctonia solani. El aceite esencial de L. turbinata mostroÌ una potente actividad antifuÌngica frente al panel de hongos ensayados, mientras que el aceite de L. integrifolia inhibioÌ significativamente el crecimiento micelial de S. rolfsii y R. solani.
Assuntos
Ascomicetos/efeitos dos fármacos , Óleos Voláteis/farmacologia , Lippia/química , Antifúngicos/farmacologia , Rhizoctonia/efeitos dos fármacos , Terpenos/análise , Óleos Voláteis/química , Espectroscopia de Ressonância Magnética , Cromatografia Gasosa-Espectrometria de Massas , Antifúngicos/químicaRESUMO
The endophytic fungus strain 0248, isolated from garlic, was identified as Trichoderma brevicompactum based on morphological characteristics and the nucleotide sequences of ITS1-5.8SITS2 and tef1. The bioactive compound T2 was isolated from the culture extracts of this fungus by bioactivity-guided fractionation and identified as 4β-acetoxy-12,13-epoxy-Δ9-trichothecene (trichodermin) by spectral analysis and mass spectrometry. Trichodermin has a marked inhibitory activity on Rhizoctonia solani, with an EC50 of 0.25 µgmL-1. Strong inhibition by trichodermin was also found for Botrytis cinerea, with an EC50 of 2.02 µgmL-1. However, a relatively poor inhibitory effect was observed for trichodermin against Colletotrichum lindemuthianum (EC50 = 25.60 µgmL-1). Compared with the positive control Carbendazim, trichodermin showed a strong antifungal activity on the above phytopathogens. There is little known about endophytes from garlic. This paper studied in detail the identification of endophytic T. brevicompactum from garlic and the characterization of its active metabolite trichodermin.