Effect of essential oils on the development of Colletotrichum sp. fungus in fragments of Feijoa sellowiana fruits

The aim of this work was to evaluate the effect of the essential oils of Syzygium aromaticum, Cymbopogon citratus, Eucalyptus citriodora and Rosmarinus officinalis on the mycelial development of the fungus Colletotrichum sp. in fragments of Feijoa sellowiana fruits. The essential oils were incorporated in the PDA (Potato-Dextrose-Agar) medium in the concentrations of 250, 500 and 1000 ppm, 0 ppm (PDA only) (negative control), and fungicide fluazinam 1% (positive control). The area under the mycelial growth curve (AUMGC) and percent inhibition of mycelial growth (PIMG) were calculated. In the second evaluation, fruits fragments bordering the disease symptom were immersed in essential oils aqueous solution of S. aromaticum, C. citratus, and E. citriodora, at the concentration of 5000 ppm, 0 ppm (water only - negative control) and fluazinam 1% (positive control). The immersion times in the treatments were: 2, 4, 8, 12 and 24 hours, with subsequent incubation in Agar-Agar medium at 25°C. This evaluation was performed daily for 15 days, observing the moment of fungal germination through the emission of the mycelium. It was verified from the obtained results that all treatments reduced the fungal growth, and the essential oils of C. citratus and S. aromaticum totally inhibited its growth from the dose 500 and 1000 ppm, respectively. Regarding the test on fruit fragments, the essential oil of S. aromaticum at the immersion times of 12 and 24 hours was effective in inhibiting the fungus until the 15th day of evaluation.

Antibacterial activity of medicinal plant extracts against Ralstonia solanacearum (Smith) that causes bacterial wilt in hot pepper (Capsicum annuum L. )

This study was conducted to evaluate the in vitro antibacterial activity of some medicinal plants against Ralstonia solanacearum. Bioactive chemicals were extracted from Burcea antidysenterica, Eucalyptus citriodora, Justicia schimperiana, Lantana camara, Melia azedarach and Ricinus communis leaves using maceration method. The bioassay was evaluated by disc diffusion method. The pathogen was isolated from infected Capsicum annuum plants using Casamino acid-Peptone-Glucose agar (CPG) medium. The isolate was identified using cultural, biochemical characteristics, pathogenicity test and found to be R. solanacearum. The methanol extracts had different composition, percentage extract yield, antibacterial activity and relative percentage inhibition. Unlike others, extracts of E. citriodora and R. communis consisted of all the tested secondary metabolites. All species showed antibacterial activity except M. azedarach. Significant differences were recorded in antibacterial activity among species and test concentrations. The highest antibacterial activity and the lowest bacteriostatic and bactericidal concentrations were found from E. citriodora and R. communis extracts. The higher potency of E. citriodora and R. communis extracts suggested the potential of the two species as a biocide to control bacterial wilt. However, further in vivo studies on these species extracts are compulsory.

Optimizing preparation of microcapsules of eucalyptus citriodora oil by bex-behnken design and response surface method / 中国药学杂志

OBJECTIVE: To optimize the preparation process of microcapsules of eucalyptus citriodora oil, and to investigate its thermal stability. METHODS: Using gelatin as the capsule materials, the microcapsules were prepared by simple coacervation. Base on single factor experiments, three factors including the concentration of gelatin, the core-wall ratio and the reaction temperature were selected to study the preparation conditions by Box-Behnken design and response surface method with its encapsulation efficiency as index. The test results were analyzed by Design-Expert 8.0.6 software. RESULTS: The optimal preparation process was as follows: gelatin solution concentration 3.27%, core-wall ratio 2.5∶1, preparation temperature 50 ℃. Under the optimized preparation process, the encapsulation rate was 67.50%, which was different from the model prediction value (65.68%) by 2.77%. The particle size was about 75 μm and relatively uniform, and the surface was relatively smooth. Moreover, thermal analysis showed that microencapsulation of eucalyptus citriodora oil could significantly increase its thermal stability. CONCLUSION: Using Box-Behnken design and response surface method to optimize the preparation process of eucalyptus citriodora oil microcapsule is accurate, effective and feasible. Microencapsulation can improve the thermal stability of eucalyptus citriodora oil.

Insect Growth Regulator (IGR) effects of Eucalyptus citriodora Hook (Myrtaceae) / Efectos tóxicos e IGR de Eucalyptus citriodora Hook (Myrtaceae)

In addition to eucalyptin the methanol extract from leaves of Eucalyptus citriodora (Myrtaceae) afforded the known compounds apigenin, chrysin, luteolin, naringenin, quercetin; together with betulinic acid, oleanolic, ursolic acid, and two remaining complex mixtures of unidentified flavonoids and triterpenes. These compounds together with triterpenes mixtures, hexane and ethyl acetate extracts showed antifeedant, insecticidal and insect growth regulatory activities against fall armyworm [Spodoptera frugiperda JE Smith (Lepidoptera: Noctuidae)] an important pest of corn, and yellow mealworm [Tenebrio molitor (Coleoptera:Tenebrionidae)] a pest of stored grains. The most active compounds were chrysin, eucalyptin, quercetin, luteolin, and betulinic and oleanolic acids and the mixtures of flavonoids and triterpenes (M1 and M2). These compounds and mixtures had IGR activity between 0.2 to 5.0 ug/mL and insecticidal effects between 5.0 and 10.0 μg/mL.The extracts were insecticidal to larvae, with lethal doses between 20-100 ug/mL. These compounds appear to have selective effects on the pre-emergence metabolism of the Lepidoptera, since in all treatments of the larvae of S. frugiperda the pupation was shortened and this process showed precociousness in relation to control. Thus, these substances may be useful as potential natural insecticidal agents.

Extracto metanolico de hojas de Eucalyptus citriodora (Myrtaceae) proporcionó además de eucalyptin, flavonoides tales como apigenina, crisina, luteolina, naringenina, quercetina; los triterpenos, ácido oleanólico, ácido ursólico betulínico, y dos mezclas complejas de flavonoides y triterpenos no identificados M1 y M2. Los flavonoides, triterpenos y mezclas de triterpenos, extractos de acetato de etilo y hexano mostraron efectos antialimentarios, insecticida y actividad reguladora de crecimiento (IGR) frente al gusano cogollero [Spodoptera frugiperda JE Smith (Lepidoptera: Noctuidae)], una plaga importante del maíz y frente al gusano de la harina [Tenebrio molitor (Coleoptera: Tenebrionidae)], una plaga de los granos almacenados. Los compuestos más activos fueron crisina, eucalyptin, quercetina, luteolina, ácido betulínico y ácido oleanólico y las mezclas de flavonoides y triterpenos (M1 y M2). Estos compuestos y mezclas mostraron actividad IGR entre 0,2 y 5,0 ug/mL y efectos insecticidas entre 5,0 y 10,0 μg/mL. Los extractos mostraron carácter insecticida para las larvas a dosis letales entre 20-100 ug/mL. Estas muestras parecen tener efectos selectivos sobre el metabolismo de pre-emergencia de los lepidópteros, ya que en todos los tratamientos de las larvas de S. frugiperda el tiempo de la pupación se acortó; este proceso muestra precocidad en relación con el control, las substancias ensayadas en este trabajo pueden ser útiles como potenciales agentes insecticidas naturales.

Composição química e atividade alelopática do óleo essencial de eucalipto / Chemical composition and allelopathic activity of the eucalyptus essential oil

Os óleos essenciais constituem um tipo de metabólito secundário de grande importância econômica e estão sendo cada vez mais estudados e utilizados como potentes inibidores de sementes e do crescimento de diversas plantas. O presente trabalho teve por objetivo a análise química qualitativa e quantitativa bem como a avaliação da atividade alelopática do óleo essencial extraído das folhas frescas de eucalipto (Eucalyptus citriodora) sobre a germinação e o desenvolvimento radicular das sementes de sorgo (Sorghum bicolor L.) e pepino (Cucumis sativus L.), cultivados em placa de Petri. O óleo essencial foi obtido por hidrodestilação, utilizando um aparelho tipo Clevenger, e analisado por cromatografia em fase gasosa com detector de ionização de chama e espectrometria de massas. Foi possível identificar doze constituintes químicos correspondendo a 97,69%, com predominância dos monoterpenos oxigenados citronelal (64,92%) e iso-isopulegol (10,20%) e do citronelol (8,25%). Os ensaios biológicos utilizando o óleo essencial mostraram que o mesmo apresenta efeito alelopático, prejudicando a germinação e o desenvolvimento da radícula das sementes de sorgo e pepino, sendo a redução da germinação mais pronunciada no sorgo, e que o aumento da concentração do óleo leva a uma redução linear na capacidade germinativa e no desenvolvimento da radícula.

Essential oils consist of a type of secondary metabolite that holds great economic importance, they have been increasingly studied and used as potent inhibitors of seeds and growth of various plants. The present work aimed at the qualitative and quantitative chemical analysis and evaluation of the allelopathic activity of the essential oil extracted from fresh leaves of eucalyptus (Eucalyptus citriodora) over the germination and root development of seeds of sorghum (Sorghum bicolor L.) and cucumber (Cucumis sativus L.), grown in a Petri dish. The essential oil was obtained by steam distillation, using a Clevenger apparatus, and analyzed by chromatography in gas phase with flame ionization detector and mass spectrometry. It was possible to identify twelve chemical constituents corresponding to 97.69%, with predominance of oxygenated monoterpenes citronellal (64.92%) and iso-isopulegol (10.20%) and citronellol (8.25%). The biological essays using the essential oil showed the presence of an allelopathic effect, affecting the germination and radicule length of sorghum and cucumber seeds, the germination reduction being more pronounced in sorghum, also the increase of the oil concentration leads to a linear decrease in the germination and in the radicule length.

Anti-proliferative effect of leaf extracts of Eucalyptus citriodora against human cancer cells in vitro and in vivo.

Six different extracts from Eucalyptus citriodora leaves were investigated for their anticancer effect. Extracts were prepared using a range of polar and non-polar solvents to leach out maximum active components. Phytochemical analysis of the extracts revealed the presence of anthraquinones, cardiac glycosides, flavonoids, saponins and tannins. Cytotoxic activity of different extracts was tested in vitro against seven human cancer cell lines from seven different tissues, such as SW-620 (colon), HOP-62 (lung), PC-3 (prostate), OVCAR-5 (ovary), HeLa (cervix), IMR-32 (neuroblastoma) and HEP-2 (liver). The ethyl acetate, chloroform and 50% methanolic extract displayed highest anti-proliferative effect in a dose-dependent manner. In vivo anti-tumor activity was evaluated against murine tumor (solid) model of Ehrlich ascites carcinoma and Sarcoma 180. The results showed that ethyl acetate and aqueous extracts suppressed the growth of Ehrlich ascites carcinoma (29.79% and 18.48%, respectively), but showed little growth inhibition in case of Sarcoma 180 (13. 86% and 8.57%, respectively). The activity might be due to the flavonoids, tannins and saponins that are present in all the extracts of the plant. Further investigation is required for the isolation of active principle(s) from the ethyl acetate extract, which has shown significant in vitro and in vivo anticancer potential.

Potenciação alelopática de extratos vegetais na germinação e no crescimento inicial de picão-preto e alface / Allelopathy of plant extracts on germination and initial growth of beggartick (Bidens pilosa L.) and lettuce (Lactuca sativa L.)

O picão-preto (Bidens pilosa L.) é uma planta daninha muito agressiva, que está presente em quase todo Brasil. O principal método de controle é o químico, porém apresenta elevado impacto ambiental, risco de intoxicação humana e possibilidade de causar fitotoxicidade as culturas. O objetivo do trabalho foi avaliar o efeito alelopático de extratos etanólicos de Eucalyptus citriodora Hook. e Pinus elliottii L. na germinação e no crescimento inicial de picão-preto e alface (Lactuca sativa L.). Foram testadas quatro concentrações de cada extrato (0,25; 0,50; 1,0 e 2,0 por cento) além do controle (0,0 por cento) água destilada com Tween 20 a 0,08 por cento. O delineamento experimental foi o inteiramente casualizado, com quatro repetições em condições de laboratório. O extrato de P. elliottii não causou efeito alelopático sobre o picão-preto e o alface. O extrato de E. citriodora reduziu significativamente o índice de velocidade de germinação (IVG) do picão-preto em todas as concentrações testadas quando comparadas com o controle (0,0 por cento), porém para a alface o IVG foi significativo apenas na concentração de 2,0 por cento. Para o comprimento da raiz não foi possível observar diferença significativa entre os tratamentos para os dois extratos testados tanto para o alface como para o picão preto.

Bidens pilosa L. is an aggressive weed found all over Brazil. The main control method for this species is chemical treatment however, causes strong environmental impact, and it has great human contamination risks, and may cause phytotoxity to crops. The objective of this study was to evaluate the effect of ethanolic extracts of Eucalyptus citriodora Hook. and Pinus elliottii L. on seed germination and initial growth of B. pilosa and lettuce (Lactuca sativa L.). Five concentrations of each extract (0.0; 0.25; 0.50; 1.0; 2.0 percent) were tested in laboratory conditions using a randomized complete block design with four replicates. P. elliottii extract had no effect on B. pilosa and lettuce. However, E. citriodora extract, significantly reduced germination index (GI) of B. pilosa, in all tested concentrations, when compared with the control composed by distilled water. Lettuce GI was affected only by 2,0 percent concentration of ethanolic extract. Extracts of both P. elliottii and E. citriodora had no significant effect on the root length parameter of both B. pilosa and lettuce.

Los análisis de patentes como base para la toma de decisiones en los proyectos de investigación: Estudio de un caso / Patent analysis as a basis for decision making in search projects: Study of a case

El pasado siglo demostró que la capacidad de innovación tecnológica de un país se ha convertido en un factor determinante en sus resultados socioeconómicos. Esta situación, entre otras causas, ha propiciado una fuerte tendencia a realizar análisis con diferentes fuentes de información especializadas, con la intención de lograr por medio de ellos una orientación para obtener innovaciones aún más exitosas y radicales. Entre estas fuentes de información se distinguen, con gran protagonismo, los documentos de patentes. La consulta y análisis con técnicas métricas de la información contenida en las patentes se ha transformado en una de las principales herramientas para modelar los escenarios tecnológicos de países, empresas, institutos de investigación, temáticas, proyectos, etcétera. Con el empleo de una serie de indicadores métricos es posible identificar patrones y tendencias a partir de la evidencia tecnológica disponible y detectar posibles redes sociales encubiertas de innovación con diferentes comportamientos en la investigación, con vista, entre otras funciones, a la toma de decisiones oportunas si esta lo requiere. Para ilustrar el procedimiento, se utilizó un caso práctico: el proyecto “Composición química de la madera, la corteza y el follaje de tres especies de eucaliptos de la provincia de Pinar del Río”. Se emplearon los registros de patentes de la base de datos de Estados Unidos como fuente de información y se procesaron con una herramienta propia, desarrollada por la Universidad de Pinar del Río y Ucinet, un software para representar las posibles redes existentes. Los resultados obtenidos posibilitaron reorientar las investigaciones hacia aspectos más prometedores.

The last century demonstrated that a country’s capacity of technological innovation has become a decisive factor of its socio-economical results. This state of affairs, among other causes, has brought about a strong tendency towards the analysis of different specialized information sources, with the intention of setting a course towards even more radical and successful innovations. Among these information sources, patent documents stand out as main protagonists. The analysis with metric techniques of the information contained in the patents has become one of the main tools for the modeling of the technological scenarios of countries, enterprises, research institutes, subject matters, projects, etcetera. Based on the use of a series of metric indicators, it is possible to identify patterns and tendencies, with the available technological evidence, as well as to detect possible unidentified innovation social webs with a different investigative behavior, which is useful for, among other functions, the making of opportune decisions if the investigation so requires. To illustrate this project was used a practical case: the project: Chemical Composition of the Wood, Bark and Foliage of Three Species of Eucalyptus in the Province of Pinar del Río. The records of patents from the United States database were used as information source, and processed with a tool of our own, developed by the University of Pinar del Río and Ucinet, a software to represent the possibly existing webs. The obtained results made possible the reorientation of the research towards more promising aspects.