Spelling suggestions: "subject:"estragole"" "subject:"estragol""
1 |
Avalia??o das atividades anti-toxopl?smica, antioxidante e antiinflamat?ria dos monoterpenos timol (lippia sidoides) e estragol (croton zenhtneri)Oliveira, Claudio Bruno Silva de 14 March 2012 (has links)
Made available in DSpace on 2014-12-17T14:10:26Z (GMT). No. of bitstreams: 1
ClaudioBSO_DISSERT.pdf: 2673133 bytes, checksum: 44082c33463f5700264efa7b77ae2f4c (MD5)
Previous issue date: 2012-03-14 / Toxoplasmosis, a benign disease in normal healthy individuals, can have serious effects in pregnant women and immunocompromised patients. It is a parasitic disease caused by Toxoplasma gondii (Tg), an obligatory intracellular protozoan. The prophylactic and therapeutic arsenal against this parasite is very restricted. Thus, there is an ongoing search for novel drugs and therapeutic strategies. A promising alternative is a rational approach using medicinal plants. This study aimed to standardize methodologies for assessing the toxicological, antiproliferative, antioxidant, antiinflammatory and anti-Toxoplasma effects of Estragole and Thymol compounds isolated from species of plants (Lippia sidoides and Croton zenhtneri) commonly used in the Cariri region of Ceara State, Brazil. First we evaluated in vivo toxicity and conducted a pathological analysis of mice livers. In vivo antiinflammatory activity was assessed using air pouch and paw edema methods. Cytotoxicity assays were performed and antiproliferative, antioxidant and nitric oxide production analyzed. Anti-Toxoplasma activity was evaluated in a congenital experimental model with varying stages of maternal infection using the ME-49 strain and a non- congenital model by using ME-49 and RH strains. The results suggest low to moderate toxicity for both compounds. Thymol was more toxic in vivo and in vitro, having greater pathological repercussion than Estragole. The compounds were inactive for antiproliferative activity. Thymol showed better antioxidant activity, while Estragole stimulated nitric oxide production in macrophages. Both showed significant antiinflammatory activity. In non-congenital Tg infection, both compounds were active only against the ME49 strain. In congenital infection, Estragole (oral route) improved the newborn weight of infected mothers compared with untreated controls. Subcutaneous administration of the two compounds increased the weight of offspring born to infected mothers compared with untreated controls. We concluded that Estragole and Thymol exhibit important biological and anti-Toxoplasma activities. Further studies are needed to elucidate the mechanism of action of these compounds and other possible activities not investigated in the present study / A toxoplasmose, doen?a de curso benigno em pacientes imunocompetentes, mas que pode ocasionar graves acometimentos cl?nicos em imunossuprimidos e gestantes ? causada pelo Toxoplasma gondii (Tg), protozo?rio intracelular obrigat?rio. O arsenal profil?tico e terap?utico contra este parasito ? bastante restrito, tornando urgente a busca por novos medicamentos. Uma alternativa promissora ? a abordagem racional a partir de plantas medicinais. Neste estudo foram padronizadas metodologias objetivando avaliar os efeitos toxicol?gicos, antiproliferativos, antiinflamat?rios, antioxidantes e anti-toxopl?smicos do Timol e Estragol isolados, respectivamente, das esp?cies vegetais Lippia sidoides e Croton zenhtneri, usadas popularmente na regi?o do Cariri/CE para diversas mol?stias. Inicialmente foram realizados testes de toxicidade in vivo e an?lise patol?gica do f?gado dos camundongos. Avaliou-se a atividade antiinflamat?ria in vivo pelo m?todo da bolsa de ar e pela medida da varia??o do edema de pata. Ensaios de citotoxicidade in vitro foram realizados, bem como pesquisas de atividade antiproliferativa, antioxidante e produ??o de ?xido n?trico. A atividade anti-toxopl?smica foi avaliada em modelo murino de infec??o n?o cong?nita (usando Tg ME-49 e Tg RH) e cong?nita, com per?odos variados de infec??o materna (Tg ME-49). Os resultados sugerem toxicidade baixa a moderada para os dois compostos. O Timol se mostrou mais t?xico, in vivo e in vitro, e teve maior repercuss?o patol?gica do que o Estragol. Os compostos foram inativos para atividade antiproliferativa. O Timol apresentou ?tima atividade antioxidante enquanto o Estragol estimulou a produ??o de ?xido n?trico em macr?fagos. Ambos apresentaram significativa atividade antiinflamat?ria. Os dois compostos foram ativos apenas contra a cepa ME-49. No modelo de infec??o cong?nita o Estragol proporcionou um aumento significativo de peso neonatal em filhotes de m?es infectadas quando comparadas com o controle n?o tratado. O mesmo ocorreu com filhotes de m?es tratadas, via subcut?nea, com ambos os compostos ap?s 30 dias. Conclui-se que o Timol e o Estragol possuem importantes atividades biol?gicas e anti-toxopl?smica. Estudos posteriores s?o necess?rios para elucidar o mecanismo de a??o destes compostos, al?m de outras poss?veis atividades n?o investigadas neste estudo
|
2 |
Toxicidad volátil de monoterpenoides y mecanismos bioquímicos en insectos plaga del arroz almacenadoLópez Belchí, María Dolores 23 October 2008 (has links)
Algunas plagas causan daños importantes en productos y granos almacenados, lo cual conlleva consecuentemente a pérdidas de producción y calidad en estos productos.Las principales plagas del arroz almacenado en España son, Sitophilus oryzae L. (Coleoptera Curculionidae), Rhyzopertha dominica Fabricius (Coleoptera: Bostrichidae), y Cryptolestes pusillus Schönherr (Coleoptera: Cucujidae). Las dos primeras son plagas primarias que atacan directamente el grano y resultan bastante destructivas debido a que sus larvas se alimentan y desarrollan dentro de él. C.pusillus es, sin embargo, una plaga secundaria que se beneficia de granos que ya están dañados y rotos.Actualmente, el uso de fumigantes e insecticidas de síntesis sigue siendo el principal método de lucha para controlar las plagas de almacén, si bien recientemente (dadas las continuas restricciones al uso de agroquímicos) existe un gran interés en la utilización de otras alternativas tales como el control biológico, el almacenamiento a bajas temperaturas, o los tratamientos con calor entre otros.Igualmente muchos productos obtenidos principalmente de plantas y que derivan del metabolismo secundario de las mismas ofrecen una fuente de bioinsecticidas que podrían representar una alternativa ecológica frente a los insecticidas de síntesis ya que su uso masivo e indiscriminado ha ocasionado problemas tales como la aparición de resistencias en determinadas especies de insectos frente a diferentes materias activas, desequilibrios ecológicos y problemas medioambientales sin olvidar el riesgo que entrañan para la salud humana.Con este trabajo se ha pretendido estudiar la actividad plaguicida de los aceites esenciales extraídos de tres plantas: Coriandrum sativum L. (Umbelliferae), Carum carvii L. (Umbelliferae) y Ocimum basilicum L. (Labiatae) y su posterior fraccionamiento para identificar dentro de estos aceites los compuestos químicos responsables de esta actividad insecticida sobre tres plagas de almacén de arroz (S. oryzae, R.dominica y C.pusillus).Del estudio de estos monoterpenoides, linalol, S-carvona y estragol resultaron tener una alta actividad insecticida sobre estas plagas. Sin embargo el E-anetol fue más selectivo para R.dominica y C.pusillus, así como el limoneno, γ-terpineno, geraniol y eucaliptol sólo resultaron activos frente a C.pusillus.Algunos monoterpenoides podrían actuar de sinergistas potenciando la actividad de otros, como podría ser el caso del alcanfor, acetato de geranilo y E-anetol con linalol en R.dominica y C.pusillus, o el caso del metoxicinamaldehido, p-anisaldehido y linalol que pueden tener efecto sinergista sobre el estragol.Este trabajo también abarcó el estudio de un posible modo de acción de estos monoterpenoides, la inhibición de la acetilcolinesterasa, para alcanzar un mayor entendimiento del comportamiento de estas sustancias en el interior del insecto.Así se pudo observar como la mayoría de monoterpenoides estudiados inhibían en cierta medida esta enzima, siendo fenchona, S-carvona y linalol los monoterpenoides que mayor inhibición originaron.Del mismo modo se observó como fenchona, γ-terpineno, geraniol y linalol inhibían competitivamente la acetilcolinesterasa, mientras que S-carvona, estragol y alcanfor producían una inhibición mixta para esta enzima.Sin embargo no se observó inhibición de la acetilcolinesterasa por parte del E-anetol a las concentraciones de monoterpenoides ensayadas.Para completar este trabajo se examinó de igual forma la capacidad que tenían estos bioinsecticidas de generar resistencia en estas tres plagas así como el mecanismo de resistencia implicado en el desarrollo de este proceso. Para ello se fueron seleccionando las poblaciones de insectos mediante la aplicación de los diferentes monoterpenoides a dosis crecientes durante 7 generaciones. De este modo se pudo calcular el factor de resistencia en cada una de las plagas y para cada uno de los monoterpenoides comparando las concentraciones letales 50 de las poblaciones seleccionadas con las poblaciones iniciales (sensibles).A continuación se analizaron tres posibles sistemas de detoxificación enzimáticos gracias al uso de sinergistas para estudiar el mecanismo de resistencia que podría estar involucrado.De tal forma se observó como estos monoterpenoides inducían lentamente resistencias resultando ventajosos en un futuro para el control de estas plagas.Esta Tesis ha englobado un estudio íntegro y profundo de estos insecticidas ecológicos desde la extracción de los aceites esenciales, seguido de la identificación de compuestos puros (CG-EM) con actividad insecticida junto con el estudio de un modo de acción de estos insecticidas, la selección de resistencia en las poblaciones de insectos y los posibles mecanismos de resistencia que pudieran estar implicados en este proceso. / Some pests cause serious damage to stored grains and stored products and consequently production and quality losses in these products.The rice weevil, Sitophilus oryzae L. (Coleoptera: Curculionidae), the lesser grain borer, Rhyzopertha dominica Fabricius (Coleoptera: Bostrichidae) and Cryptolestes pusillus Schönherr (Coleoptera: Cucujidae) were the main damaging pests found in stored rice in Spain.S.oryzae and R.dominica are primary pests attacking directly the intact grain and are quite destructive because their larvi feed and develop inside the grain whereas C.pusillus is a secondary pest which benefits from grains previously damaged.At the present time, organic synthetic pesticides are still the main method to control stored grain pests, however, recently (due to restriction in agrochemicals use) there is a great interest in using other altenatives such as biological control, storage at low-temperatures, or heat treatment.Likewise, many products obtained mainly from plants and derived from secondary metabolism have insecticidal activity against insects, such as monoterpenoids, which present a broad variety of bioinsecticide products which could turn out to be an ecologic alternative to synthetic pesticides since the majority of alternative products are not harmful for the human healthy and they become less environmentally damaging, exhibiting a low impact on the environment.In addition, it cannot be ignored the different difficulties related to resistance due to several active compounds from organic pesticides found in some species of insects.With this work, we have considered remarkable to study the insecticide activity of essential oils extracted from three plants: Coriandrum sativum L. (Umbelliferae), Carum carvii L. (Umbelliferae) and Ocimum basilicum L. (Labiatae) and carry out a bioassay-guided fractionation of their essential oils to identify which compounds were responsible for the volatile toxicity shown on three stored rice pests (S. oryzae, R. dominica and C. pusillus).Linalool, S-carvone and estragole turned out to have a high insecticide activity on these pests. Nevertheless E-anetol was more selective to R. dominica and C. pusillus, being only active on C. pusillus limonene, γ-terpinene, geraniol and eucalyptol.Some monoterpenoids were found as synergists, increasing the activity of the other ones, like for instance, camphor, geranyl acetate and E-anethole with linalool in R.dominica and C.pusillus or metoxycinnamaldehyde, p-anysaldehyde and linalool which could activate to estragole.In this work, the inhibition of acetylcholinesterase as a posible mode of action was studied as well, to reach a clear understanding about the action of these products inside the insects.The majority of monoterpenoids inhibited the enzyme acetylcholinesterase being fenchone, S-carvone and linalool the monoterpenoids that produced a higher inhibition.Furthermore, it was observed how fenchone, γ-terpinene, geraniol and linalool showed a competitive inhibition whereas S-carvone, estragole and camphor produced a mixed inhibition for this enzyme. However the enzyme acetylcholinesterase was not inhibited by E-anethole.To finish up this work, the selection for monoterpenoid resistance on these pests as well as the metabolic mechanisms implicated was studied.The resistant strains were selected from susceptible insect populations and survivors were reared separately for each monoterpenoid and successive generations were treated with higher concentrations. These populations were selected until seven times.As a result we could calculate the resistance factor on each pest (comparing lethal concentration 50 values of susceptible and resistant strains).Next, three enzymatic systems detoxifying these monoterpenoids were analysed to study the metabolic mechanism implicated.In this way we could realize that all monoterpenoids induced resistance slowly, concluding that these pesticides will be appropriated to control these pests in the future.This Thesis has concerned a study in depth about ecological insecticides from extraction of essential oils, identification of compounds (GC-MS) with insecticide activity, mode of action and study of resistance and mechanism of insecticide resistance involved in this process.
|
Page generated in 0.3096 seconds