The essential oil obtained from leaves and stem barks of the Southern Brazilian native Drimys brasiliensis Miers, a tree with medicinal properties, was analyzed by gas chromatography (GC) and GC/mass spectrometry (MS). The oil was characterized by sesquiterpenoids (66%), cyclocolorenone being the most abundant (30.4%), followed by bicyclogermacrene (11.8%) and alpha-gurjunene (6.0%). Laboratory tests were carried out to determine the toxicity of the essential oil on larvae of the cattle tick Rhipicephalus (Boophilus) microplus and the brown dog tick Rhipicephalus sanguineus by the larval immersion test. It was observed that the oil was lethal, killing 100% of the larvae of both ticks at the doses of 25, 12.5, and 6.25 microl/ml. The lowest dose tested, 3.125 microl/ml, was also toxic, killing 95-98% of the larvae.

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In addition to some usual fatty adds, the seed oil of Jodina rhombifolia (Santalaceae) contains nine acetylenic fatty acids [9-octadecynoic acid (stearolic acid) (1.1%), trans-10heptadecen-8-ynoic acid (pyrulic acid) (20.1%), 7-hydroxytrans-l(~heptadecen-8,ynoic acid (2.3%), trans-10,16-heptadecadien-8-ynoic acid (0.7%), 7-hydroxy-trans-10,16-hepta-decadien~-ynoic acid (0.1%), trans~ll~actadecen-~ynoic acid (ximenynic acid) (20.3%), 8-hydroxy-trans-ll-octadecen-~ ynoic acid (12.2%), trans-ll,17-octadecadien-9-ynoic acid (1.5%), 8-hydroxy-trans-ll,17-octadecadien-9-ynoic acid (1.3%), 9-hydroxystearic acid (<0.1%) and 9,10-epoxystearic acid (0.7%)]. The fatty acids have been analyzed by gas chromatography/mass spectrometry of their methyl ester and 4,4-dimethyloxazoline derivatives. The hydroxy fatty acid methyl esters have been examined also as trlmethyl-sUyl ethers. Furthermore, the fatty acid methyl esters (FAME) have been fractionated according to their polarity (FAMF_~A: nonhydroxy; FAMF~B: hydroxy fatty acids) and to their degree of unsaturation (FAME-A1/A2; FAME-BI/B2) by preparative thin-layer chromatography and argentation chromatography, respectively. All of these fractions have been analyzed by ultraviolet and infrared spectroscopy, and the fractions FAME-A and FAME-B have been analyzed further by nuclear magnetic resonance (1H, 13C, 2D H/C, attached proton test) spectroscopy and gas chromatography/mass spectrometry.KEY WORDS: Acetylenic fatty acids, epoxy fatty acids, gas chromatography/mass spectrometry of 4,4-dimethyloxazoline derivatives of acetylenic fatty acids, hydroxy fatty acids, Jod/na rhombifolia, NMR spectroscopy, Santalaceae.

RESUMO: "Efeito inibitório de extratos de Hypericum myrianthum e H. polyanthemum sobre a germinação e crescimento de Lactuca sativa L". Neste trabalho foi investigado o efeito inibitório de extratos etanólicos de partes aéreas de Hypericum myrianthum e Hypericum polyanthemum sobre a germinação e o crescimento de alface (Lactuca sativa). A germinação das sementes foi reduzida em todas as concentrações avaliadas. Após sete dias, o percentual de germinação foi signifi cativamente retardado pelos extratos de ambas as plantas, nas maiores concentrações, em comparação com o grupo controle. O comprimento das radículas foi signifi cativamente afetado, estas apresentando alguns sinais de necrose. As duas espécies apresentam compostos fenólicos como constituintes principais, os quais podem ser responsáveis pela inibição da germinação e crescimento de Lactuca sativa. Unitermos:Hypericum myrianthum, Hypericum polyanthemum, Lactuca sativa, atividade alelopática, radícula, germinação de sementes.ABSTRACT: Germination and growth inhibitory effects of ethanolic crude extracts of Hypericum myrianthum and H. polyanthemum aerial parts on lettuce (Lactuca sativa) were investigated. The germination was retarded in all the tested concentrations. After seven days the fi nal germination percentage of the most concentrated extracts was signifi cantly reduced by both extracts in comparison with the control. The radicles length was signifi cantly affected showing necrosis. Both species present phenolic compounds as the main components and they could be responsible for the inhibition of the germination and growth of Lactuca sativa.

RESUMO:Os óleos voláteis das folhas e infl orescências de Eupatorium polystachyum DC. (Asteraceae), coletado no Rio Grande do Sul, Brasil, foram caracterizados por CG-EM e sua atividade antioxidante foi avaliada utilizando-se o método de DPPH. Foram obtidos rendimentos de 1,6 e 0,9% de óleo em relação às folhas e infl orescências frescas, sendo identifi cados 34 compostos, correspondendo a 99,1 e 99,5% do óleo volátil, respectivamente. Os óleos apresentaram exclusivamente compostos terpênicos, sendo que as folhas contêm grande quantidade de monoterpenos (66,4%) enquanto que as infl orescências apresentaram quantidades equivalentes de mono e sesquiterpenos (51,8 e 47,7%, respectivamente). As amostras apresentaram-se qualitativamente muito semelhantes sendo constituídas majoritariamente por: β-pineno (14,7 e 9,8%), β-mirceno (15,3 e 10,8%) e limoneno (22,8 e 20,5%) entre os monoterpenos e β-cariofi leno (10,4 e 15,4%), germacreno D (7,2 e 9,4%) e biciclogermacreno (12,0 e 19,2%) entre os sesquiterpenos. As diferenças entre as amostras foram basicamente quantitativas. Os óleos apresentaram atividade antioxidante pelo ensaio com DPPH por bioautografi a na diluição de 1:10 em éter etílico (v/v). Unitermos: Eupatorium polystachyum, óleos voláteis, atividade antioxidante, DPPH.ABSTRACT: "Chemical composition and antioxidant activity of the volatile oil from Eupatorium polystachyum DC". The essential oil obtained from leaves and fl owers of Eupatorium polystachyum DC. (Asteraceae) collected in Rio Grande do Sul State, Brazil, was characterized by GC-MS and its antioxidant activity was assessed by DPPH assay. The yield of essential oil, relative to fresh material, was 1.6 and 0.9% for leaves and fl owers, respectively. Both oils are constituted exclusively by terpenic compounds. Leaf oil contains great quantity of monoterpenes (66.4%); on the other hand, infl orescence oil contains comparable quantities of mono-and sesquiterpenes (51.8 and 47.7%, respectively). The same compounds are majority in both oils: β-pinene (14.7 and 9.8%), β-myrcene (15.3 and 10.8%) and limonene (22.8 and 20.5%) among monoterpenes and β-caryophyllene (10.4 and 15.4%), germacrene D (7.2 and 9.4%) and bicyclogermacrene (12.0 and 19.2%) among sesquiterpenes. The oils had antioxidant activity by DPPH assay in 1:10 dilution in ethyl ether (v/v).