The essential oils from leaves and inflorescences of Hyptis martiusii Benth were analyzed by GC-MS. Twenty-six compounds representing 93.2% of the essential oil of leaves were characterized; Delta-3-carene (22.5%), 1,8-cineole (24.27%), beta-caryophyllene (6.15%), and bicyclogermacrene (6.32%) were found as the major components. In the essential oil of inflorescences 27 compounds representing 87.7% of the oil were identified. The major components were Delta-3-carene (13.5%), alpha-pinene (5.78%), beta-caryophyllene (6.59%), viridiflorene (8.25%), and germacrene B (5.21%). The essential oil of leaves and 1,8-cineole showed pronounced insecticidal effect against Aedes aegypti larvae and Bemisia argentifolii, the vectors of dengue fever and white fly fruit plague, respectively.

-In the search for alternative chemical control against Aedes aegypti L., many researches are developed and encouraged in order to find new insecticidal plant substances. In this work, the larvicidal effect of ten essential oils was tested on A. aegypti. The oils were extracted by steam distillation and their chemical composition determined by GL-chromatography coupled with mass spectroscopy. The essential oils were diluted in aqueous solutions of dimethyl sulfoxide with concentrations of: 100, 50, 10, and 1 mg/ml. The larvicidal activity, based on the percentage of larval mortality, was evaluated after 24h exposure to the treatments. The essential oil of Vanillosmopsis arborea Baker presented the highest larvicidal activity, with CL 50 of 15.9 mg/ml and CL 90 of 28.5 mg/ml. On the other hand the essential oil of O. gratissimum L. showed the lower activity with CL 50 de 95,80 mg/ml and CL 90 de 102,86 mg/ml. The results indicate that the tested essential oils, and particularly the V. arborea, are composed by substances with larvicidal properties for A. aegypti.KEY WORDS: Dengue, plant extract, control, mosquito RESUMO -Na busca por controle químico alternativo contra Aedes aegypti L., muitas pesquisas são desenvolvidas e estimuladas no intuito de se descobrirem novas substâncias inseticidas de origem vegetal. Neste trabalho, o efeito larvicida de dez óleos essenciais foi avaliado contra A. aegypti. Os óleos foram obtidos por arraste a vapor e sua composição química foi determinada por cromatografia gasosa acoplada a espectrometria de massa. Os óleos essenciais foram diluídos em solução aquosa de dimetil sufóxido nas concentrações: 100, 50, 10 e 1 mg/ml. A atividade larvicida, baseada na percentagem de larvas mortas, foi avaliada 24h após o tratamento. O óleo essencial de Vanillosmopsis arborea Baker induziu a maior atividade larvicida, com CL 50 de 15,9 mg/ml e CL 90 de 28,5 mg/ml., enquanto o de O. gratissimum L. apresentou a menor atividade com CL 50 de 95,80 mg/ml e CL 90 de 102,86 mg/ml. Os resultados indicam que os óleos essenciais avaliados, principalmente o de V. arborea, são compostos por substâncias com efeito larvicida contra A. aegypti.

SUMMARYGuava leaf tea of Psidium guajava Linnaeus is commonly used as a medicine against gastroenteritis and child diarrhea by those who cannot afford or do not have access to antibiotics. This study screened the antimicrobial effect of essential oils and methanol, hexane, ethyl acetate extracts from guava leaves. The extracts were tested against diarrhea-causing bacteria: Staphylococcus aureus, Salmonella spp. and Escherichia coli. Strains that were screened included isolates from seabob shrimp, Xiphopenaeus kroyeri (Heller) and laboratory-type strains. Of the bacteria tested, Staphylococcus aureus strains were most inhibited by the extracts. The methanol extract showed greatest bacterial inhibition. No statistically significant differences were observed between the tested extract concentrations and their effect. The essential oil extract showed inhibitory activity against S. aureus and Salmonella spp. The strains isolated from the shrimp showed some resistance to commercially available antibiotics. These data support the use of guava leaf-made medicines in diarrhea cases where access to commercial antibiotics is restricted. In conclusion, guava leaf extracts and essential oil are very active against S. aureus, thus making up important potential sources of new antimicrobial compounds.

The antidiabetic activity of aqueous, ethanolic and hexanic extracts of Bauhinia forficata was investigated in a model of alloxan-induced diabetes in rats. The biochemical parameters studied were: plasma glucose, serum triglycerides, cholesterol, high density lipoprotein (HDL), and low density lipoprotein (LDL). Extracts were administered daily for 7 d at doses of 200 and 400 mg/kg, p.o., 48 h after alloxan injection (60 mg/kg, i.v.). The alloxan-diabetic rats showed significant reductions in plasma glucose, triglycerides, total cholesterol and HDL-cholesterol after treatment with the extracts and glibenclamide (used as standard) as compared to the diabetic controls. Levels of LDL were not altered. In conclusion, our results showed that the plant extracts when administered by gavage may reduce glucose, triglycerides, total cholesterol and HDL-cholesterol levels. These results suggest the validity of the clinical use of B. forficata in the treatment of diabetes mellitus type II.

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