Avaliação da atividade repelente do timol, mentol, salicilato de metila e ácido salicilico sobre larvas de Boophilus microplus (Canestrini, 1887) (Acari: Ixodidae) Evaluation of repellent activity of thymol, menthol, methyl salicylate and salicylic acid on Boophilus microplus larvae (Canestrini, 1887) (Acari: Ixodidae)

Verificou-se a atividade repelente do timol, mentol, ácido salicílico e salicilato de metila sobre larvas de Boophilus microplus. Essas substâncias foram usadas em emulsões em dimetilsulfuxido aquoso a 1% ou solução aquosa. Para cada substância foram testadas três concentrações, 1,0%; 0,5% e 0,25%, com cinco repetições cada. Cerca de 100 larvas, com 21 dias de idade, foram inseridas na base de hastes de madeira para avaliação da repelência, a cada duas horas, totalizando 12 horas. As concentrações mais elevadas apontaram que as quatro substâncias causaram alteração no comportamento das larvas. Timol, com mortalidade de 65% e 35% de repelência e mentol e salicilato de metila, ambos com 80% de repelência foram os mais eficientes.The repellent activity of thymol, menthol, salicylic acid and methyl salicylate on Boophilus microplus larvae was studied. These substances were tested according to their solubility: emulsions in 1% aqueous dimethylsulphoxide or in pure water. Three concentrations were tested for each substance, 1.0%, 0.5% and 0.25%, with five repetitions for each. Approximately 100 larvae at 21 days of age were placed on the base of wooden sticks and then observed for repellent action every two hours, during twelve hours. The results obtained from the higher concentrations showed that the four substances caused alterations on the larvae behavior. However, thymol (65% of mortality and 35% of repellency), menthol (80% of repellency) and methyl salicylate (80% of repellency) were the most efficient

Avaliação da atividade moluscicida do látex de três espécies de Euphorbia (Euphorbiaceae) sobre Leptinaria unilamellata d'Orbigny, 1835 (Gastropoda - Subulinidae) Assessment of moluscicidal activity of the latex of three Euphorbia (Euphorbiaceae) species on Leptinaria unilamellata d'Obigny 1835 (Gastropoda - Subulinidae)

Gastrópodes pulmonados terrestres podem atuar como hospedeiros intermediários de helmintos. Os primeiros registros do controle químico desses invertebrados datam do início do século XX e as substâncias utilizadas eram toxinas inespecíficas já empregadas no controle de outras pragas. Moluscicidas sintéticos apresentam limitações técnicas que estimularam a busca de substitutos naturais. Dentre as várias espécies vegetais com atividade moluscicida, Euphorbia cotinifolia L., Euphorbia milii des Moul. var. splendens (Bojer ex Hook) Ursch & Leandri e Euphorbia tirucalli L. despertam atenção pelos excelentes resultados obtidos sobre moluscos aquáticos. Contudo, estudos sobre a atividade de plantas moluscicidas em moluscos terrestres são pouco comuns, apesar de sua grande importância parasitológica e agrícola. As semelhanças anatomo-fisiológicas entre espécies de moluscos aquáticos e terrestres sugerem que estratégias de controle químico possam ter eficiência semelhante para os dois grupos de invertebrados. Com base nessa hipótese, o presente trabalho teve como objetivo avaliar a atividade moluscicida do látex de três espécies do gênero Euphorbia sobre Leptinaria unilamellata d'Orbigny, 1835, gastrópode terrestre descrito como hospedeiro intermediário de helmintos trematódeos digenéticos que parasitam animais domésticos. Destas E. milii var. splendens apresentou efeito moluscicida elevado sobre L. unilamellata, 100% até uma diluição de 1:800, já nos primeiros minutos após a aplicação. Embora citadas na literatura como tóxicas para moluscos aquáticos, E. cotinifolia e E. tirucalli não exibiram atividade moluscicida sobre L. unilamellata. Os resultados do presente estudo indicam que o látex de E. milii var. splendens pode se constituir em uma estratégia viável de controle químico de moluscos terrestres.<br>Pulmonate terrestrial gastropods can be intermediate hosts for helminthes. The first records of chemically controlling these invertebrates date back to the beginning of the 20th century. The substances used were unspecific toxins which were already used for controlling other pests. Synthetic molluscicides have technical limitations that stimulated a search for natural substitutes. Among the many vegetal species that have molluscicidal activity, Euphorbia cotinifolia L., Euphorbia milii des Moul. var. splendens (Bojer ex Hook) Ursch & Leandri and Euphorbia tirucalli L. call attention because of the excellent results that have been obtained when they are used on aquatic mollusks. However, studies on the activity of molluscicidal plants on terrestrial mollusks are rare, in spite of its great importance in controlling parasites and to agriculture. Anatomical and physiological similarities among species of aquatic and terrestrial mollusks suggest that chemical control strategies can be effective on both groups of invertebrates. Based on this hypothesis, we assessed the molluscicidal activity of the latex of three species of the genus Euphorbia on the terrestrial gastropod Leptinaria unilamellata d'Orbigny, 1835, described as an intermediate host of digenetic trematode helminths that parasitize domestic animals. E. milii var. splendens had the highest molluscicidal effect on L. unilamellata, being 100% lethal in concentrations up to 1:1800 in the first minutes after application. Although E. cotinifolia and E. tirucalli have been cited in the literature as toxic to aquatic mollusks, they did not have molluscicidal activity on L. unilamellata. The results of our study indicate that the latex of E. milii var. splendens may be a viable strategy for the chemical control of terrestrial mollusks

Screening antimycobacterial activity of Baccharis dracunculifolia, Centella asiatica, Lantana camara and Pterodon emarginatus

ABSTRACT The permanent investigation of new antimycobacterial drugs is necessary for the eradication programs of tuberculosis and other mycobacterium-related diseases. The aim of the present study is to search for new sources of antimycobacterial drugs using plant materials. In this study, 11 plant materials (extracts, essential oils and some fractions) obtained from 4 species of medicinal plants traditionally used as general therapeutics for different illnesses and specifically as treatment of tuberculosis, were evaluated using the microplate resazurin assay against 2 species of the Mycobacterium tuberculosis Complex and 3 nontuberculous mycobacteria. The results showed the hexane extract and the essential oil from fruits of Pterodonemarginatus (Vogel) as potential sources of antimycobacterial drugs against 4 species of tested mycobacteria. The hexane fraction of methanol extract from leaves of Centella asiatica also presented significant mycobacterial growth inhibition, but against M. chelonae only. In conclusion, it was possible to contribute to the antimycobacterial investigations by presenting three new samples of plants with significant antimicrobial activity against four Mycobacteriumspp and suggest future studies about the antimycobacterial properties of fruits from P. emarginatus

Phytotoxicity of the extracts of Lonchocarpus muehlbergianus Hassl. (Fabaceae) leaflets and galls on seed germination and early development of lettuce

Galls induced by Euphalerus ostreoides (Hemiptera: Psyllidae) cause structural and chemical alterations on Lonchocarpus muehlbergianus leaflets. Healthy and galled leaflet tissues of this plant species are rich in secondary metabolites with potential allelopathic effects. This research compares the allelopathic effects of the aqueous extracts of L. muehlbergianus leaflets and galls on seeds and seedlings of Lactuta sativa, and evaluates the chemical impact produced by a gall-inducing insect on the other trophic levels associated with it. The extracts were obtained through static maceration in distilled water (5% p/v). The treatments consisted of aqueous crude extracts and those previously filtered in polyvinylpirrolidone (PVP). After seven days, seedling height was measured, and the radicles were fixed in FAA50 for anatomical analyses. Healthy leaflet and gall aqueous extracts, and those filtered in PVP, significantly inhibited seed germination, with no significant differences between the two groups. Treatments with aqueous extracts reduced seed germination speed and vegetative axis length. Plant tissue alterations confirm the phytotoxicity of allelochemical substances present in the extracts. The differences among the treatments indicated that gall formation altered L. muehlbergianus leaflet metabolism, and this could influence the other trophic levels associated with this gall inducing-host plant system