RESUMO Os óleos essenciais apresentam possibilidade de serem empregados nas indústrias de alimentos, bebidas, produtos de higiene pessoal e cosméticos para evitar ou reduzir a deterioração lipídica e a contaminação por micro-organismos. Este trabalho teve como objetivos avaliar as propriedades funcionais antimicrobianas e antioxidantes de óleos essenciais de folhas frescas de Coniza bonariensis, Parthenium hysterophorus, Tithonia diversifolia, Ambrosia polystachya, Hedychium coronarium e Baccharis dracunculifolia, extraídos por hidrodestilação. O potencial antioxidante foi avaliado pelas metodologias do consumo do radical DPPH e da inibição da oxidação do sistema β-caroteno/ácido linoleico. A sensibilidade das bactérias Salmonella Cholerasuis, Listeria monocytogenes, Staphylococcus aureus e Escherichia coli frente aos óleos essenciais foi determinada pela utilização do método de difusão em cavidade ágar. Os óleos essenciais destacaram-se pelo elevado conteúdo de terpenoides. Todos os óleos essenciais avaliados pela metodologia do sequestro do radical DPPH não apresentaram CI50 significativos. Pela metodologia do β-caroteno/ácido linoleico, os óleos essenciais de T. diversifolia e H. coronarium não apresentaram atividades significativas e os de C. bonariensis, P. hysterophorus, A. polystachya, e B. dracunculifolia apresentaram CI50 superiores a maior concentração avaliada. Os óleos essenciais das espécies C. bonariensis, T. diversifolia, H. coronarium e de B. dracunculifolia apresentaram atividade antibacteriana para bactérias Gramnegativas e Gram-positivas, com exceção do óleo volátil de P. hysterophorus, que não impediu o crescimento de nenhuma das cepas bacterianas testadas. O óleo essencial de A. polystachya apresentou potencial antibacteriano apenas nas cepas de S. aureus.

ABSTRACT Essential oils can be employed in the food, drinks, toiletry and cosmetics industries to prevent or reduce lipid deterioration and contamination by microorganisms. The aim of this work was to evaluate the functional antimicrobial and antioxidant properties of essential oils of fresh leaves from Coniza bonariensis, Parthenium hysterophorus, Tithonia diversifolia, Ambrosia polystachya, Hedychium coronarium and Baccharis dracunculifolia, extracted by hydrodistillation. The methodologies used for assessing antioxidant potential were consumption of the DPPH radical and oxidation inhibition of the β-carotene/linoleic acid system. Sensitivity of the bacteria Salmonella cholerasuis, Listeria monocytogenes, Staphylococcus aureus and Escherichia coli to the essential oils was determined using the agar-well diffusion method. The essential oils were noteworthy for their high terpenoid content. None of the essential oils assessed by DPPH radical sequestration presented significant IC50. Using β-carotene/linoleic acid methodology, the essential oils of T. diversifolia and H. coronarium showed no significant activity, and C. bonariensis, P. hysterophorus, A. polystachya and B. dracunculifolia showed IC50 greater than the highest concentration evaluated. The essential oils of C. bonariensis, T. diversifolia, H. coronarium and B. dracunculifolia displayed antibacterial activity for gram-negative and grampositive bacteria, with the exception of the volatile oil of P. hysterophorus, which did not inhibit growth in any of the bacterial strains tested. The essential oil of A. polystachya displayed antibacterial activity only for strains of S. aureus.

ABSTRACT Essential oils are pharmacologically active and unexplored compounds. The inhibitory properties of essential oils from Baccharis dracunculifolia, Conyza bonariensis, Tithonia diversifolia and Ambrosia polystachya were evaluated in the coagulation and fibrinogenolysis induced by snake venoms. The essential oil from Conyza bonariensis extended the clotting time of Lachesis muta from 52.2 to 115.2 seconds and that of Bothrops moojeni from 108.3 to 2340.0 seconds, when pre-incubated with the venoms. The longest clotting times for Bothrops atrox venom were observed after incubation with the essential oils from Conyza bonariensis and Tithonia diversifolia: the times increased from 100.8 to 264.0 and 227.7 seconds, respectively. The prior incubation of the essential oils with plasma and subsequent addition of Lachesis muta venom resulted in a pro-clotting effect. The oils from Ambrosia polystachya and Baccharis dracunculifolia caused 100% of inhibition on the fibrinogenolysis induced by Bothrops moojeni and Lachesis muta venoms (the oils were previously incubated with the venom). The results indicate that the essential oils show promise as adjuvants for the treatment of snakebites.

RESUMOOs óleos essenciais apresentam potencial para serem empregados como bioherbicidas, possuindo vantagens em função da sua biodegradabilidade, elevada diversidade estrutural e reduzida resistência natural às plantas daninhas. Os óleos essenciais das folhas e dos rizomas de Hedychium coronarium, planta invasora exótica adaptada a diferentes regiões do Brasil, foram extraídos por hidrodestilação e caracterizados quimicamente por Cromatografia Gás-Líquido e Cromatografia Gás-Líquido/Espectrometria de Massas. As atividades alelopáticas foram determinadas pelas metodologias que avaliam os efeitos voláteis e o contato direto dos mesmos sobre a germinação de sementes e vigor de plântulas de alface. Os constituintes majoritários do óleo essencial das folhas foram o β-pineno (46,9%), o α-pineno (19,2%) e o β-cariofileno (13,2%) e o dos rizomas, o β-pineno (41,5%), o 1,8-cineol (23,6%) e o α-pineno (13,1%). Analisando os efeitos voláteis dos óleos essenciais, observou-se que o aumento das concentrações dos mesmos não alterou a primeira contagem de plântulas germinadas e a germinação total. Em relação ao IVG, à massa seca e ao comprimento das partes radiculares e aéreas das plântulas, o óleo essencial dos rizomas foi mais efetivo que o óleo essencial das folhas nas reduções da resposta das variáveis. Ao avaliar o efeito do contato direto dos óleos essenciais observou-se que ambos reduziram a resposta de todas as variáveis avaliadas e que, adicionalmente, o óleo dos rizomas provocou reduções superiores à do óleo das folhas em todas as variáveis. Estes resultados podem ser atribuídos ao maior conteúdo monoterpênico presente no óleo essencial dos rizomas, destacando-se a presença do 1,8-cineol.

ABSTRACTEssential oils have the potential to be used as bioherbicides, and possess the advantage of their biodegradability, high structural diversity and reduced natural resistance to weeds. The essential oils of the leaves and rhizomes of Hedychium coronarium, an exotic invasive plant adapted to different regions of Brazil, were extracted by hydrodistillation and characterised chemically by Gas-Liquid Chromatography and Gas-Liquid Chromatography/Mass Spectrometry. Allelopathic activity was determined using methodologies that evaluate the effects of volatility and direct contact on seed germination and seedling vigour in the lettuce. The major constituents of the essential oil from the leaves were β-pinene (46.9%), α-pinene (19.2%) and β-caryophyllene (13.2%) and from the rhizomes, β-pinene (41.5%), 1.8-cineole (23.6%) and α-pinene (13.1%). When analysing the volatile effects of the essential oils, it was seen that their concentration did not affect seedling first germination count or total germination. The essential oil from the rhizomes was more effective than the essential oil from the leaves in reducing seedling response for SGI, dry weight, and length of the roots and shoots. When evaluating the effect of direct contact with the essential oils, it was seen that both oils reduced the response of all the variables under evaluation, and that in addition, the oil from the rhizomes caused greater reductions than that from the leaves, again for all variables. These results can be attributed to the higher levels of monoterpenes present in the essential oil from the rhizomes, mainly the presence of 1.8-cineole.