RESUMO
Microscopic anatomy and volatile secondary metabolites at three stages of development of the inflorescences of Lantana camara (Verbenaceae). Plants of the Verbenaceae family, like L. camara, have called the attention of researchers, not only because of its high diversity and its distribution around the world, but also for its variable use as popular medicine to treat diseases like tetanus, rheumatism and malaria, and as bactericide and insecticide. To assess this, the morphology and ontogeny of the inflorescences of Lantana camara and the chemical composition of volatile secondary metabolites were analyzed at three different ontogeny stages. Plants were collected from the experimental crop area in CENIVAM, Bucaramanga, Colombia. Fresh inflorescence stages were established and analyzed using a stereoscopic microscope, fixed in FAA and included in parafine. Transversal and longitudinal 10μm thick sections were prepared using a rotative microtome, safranine-fastgreen stained and were observed and photographed using a light microscope. The chemical composition of volatile secondary metabolites were analyzed for each stage. The analytes, obtained from 0.7g of plant, were isolated by solid phase micro-extraction in the headspace mode (HS-SPME) and were placed in 20ml vials. The components were analyzed by gas chromatography coupled to mass spectrometry (GC-MS). Stage I was microscopically characterized by an immature development in which the meristematic differentiation begins with a mass of cells. In Stage II, the morphogenetic movement gives way to the formation of the respective floral sexual structures, calyx and corolla. In Stage III, the different organs are conspicuous: four stamens epipetals and didynamous, monocarpelar, biloculate and globose gynoecium, upper ovary and lateral stigma; the flowers are hermaphroditic. The main secondary metabolites detected by GC-MS were bicyclosesquiphellandrene, E-β-farnesene, E-β-caryophyllene, Υ-muurolene + Υ- curcumene and α-zingiberene. Nevertheless, this study reports for the first time in plant species α-gurjunene, Υ-amorphene, α-muurolene, sesquithujene, α-trans-bergamotene and transcadina-1,4-diene. The diversity of compounds found can be only explained by the extraction methods employed, the developmental stages and section of the plant, the geographic conditions, collection time and the genetic constitution of the evaluated species. Rev. Biol. Trop. 59 (1): 473-486. Epub 2011 March 01.
Las plantas de la familia Verbenaceae, entre ellas la especie Lantana camara L., poseen una alta diversidad botánica además de su variable uso. Se describe el avance morfoanatómico de tres etapas de desarrollo de las inflorescencias de L. camara L. (Verbenaceae), recolectadas en Bucaramanga, Colombia. Para esto se tincionaron las estructuras vegetales mediante la técnica fast-green, previo a los análisis con microscopía óptica convencional. El aislamiento de los analitos de cada estadio se realizó mediante la técnica de microextracción en fase sólida en el modo headspace (HS-SPME) y su posterior análisis de componentes, mediante cromatografía de gases acoplada a espectrometría de masas (GC-MS). En el Estadio I se apreció un grupo de células en donde se inicia la diferenciación meristemática. En el Estadio II, los movimientos morfogenéticos dan paso a la formación de las respectivas estructuras sexuales florales, el cáliz y la corola. Al llegar al Estadio III, se observaron claramente los diferentes órganos. Los metabolitos detectados en este estudio y que no fueron encontrados en la bibliografía revisada fueron, el α- gurjuneno, el Υ-amorfeno, el α-muuroleno, el sesquitujeno, el α-trans- bergamoteno y el trans-cadina-1,4-dieno. Los principales metabolitos secundarios detectados fueron: biciclosesquifelandreno, E-β-farneseno, E-β-cariofileno, Υ- muuroleno+Υ-curcumeno y α-zingibereno. Una función importante de éstas y otras esencias florales es la defensa y la protección durante el estrés abiótico de la planta.
Assuntos
Inflorescência/química , Lantana/química , Colômbia , Cromatografia Gasosa-Espectrometria de Massas , Inflorescência/metabolismo , Lantana/anatomia & histologia , Lantana/metabolismo , VolatilizaçãoRESUMO
Background & objectives: Development of insect resistance to synthetic pesticides, high operational cost and environmental pollution have created the need for developing alternative approaches to control vector-borne diseases. In the present study we have investigated the insecticidal activity of essential oil isolated from the leaves of Lantana camara against mosquito vectors. Methods: Essential oil was isolated from the leaves of L. camara using hydro-distillation method. Bioassay test was carried out by WHO method for determination of adulticidal activity against mosquitoes. Different compounds were identified by gas chromatography-mass spectrometry analysis. Results: LD50 values of the oil were 0.06, 0.05, 0.05, 0.05 and 0.06 mg/cm2 while LD90 values were 0.10, 0.10, 0.09, 0.09 and 0.10 mg/cm2 against Ae. aegypti, Cx. quinquefasciatus, An. culicifacies, An. fluvialitis and An. stephensi respectively. KDT50 of the oil were 20, 18, 15, 12, and 14 min and KDT90 values were 35, 28 25, 18, 23 min against Ae. aegypti, Cx. quinquefasciatus, An. culicifacies, An. fluviatilis and An. stephensi, respectively on 0.208 mg/cm2 impregnated paper. Studies on persistence of essential oil of L. camara on impregnated paper revealed that it has more adulticidal activity for longer period at low storage temperature. Gas chromatographic-mass spectrometric analysis of essential oil showed 45 peaks. Caryophyllene (16.37%), eucalyptol (10.75%), α-humelene (8.22%) and germacrene (7.41%) were present in major amounts and contributed 42.75 per cent of the total constituents. Interpretation &conclusion: Essential oil from the leaves of L. camara possesses adulticidal activity against different mosquito species that could be utilized for development of oil-based insecticide as supplementary to synthetic insecticides.