Chemical characterisation and allelopathic potential of essential oils from leaves and rhizomes of white ginger

Abstract

-Essential 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 -pinene (46.9%), -pinene (19.2%) and -caryophyllene (13.2%) and from the rhizomes, -pinene (41.5%), 1.8-cineole (23.6%) and -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.Key words: Volatile oils. Hedychium coronarium. Allelopathy.RESUMO -Os 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 -pineno (46,9%), o -pineno (19,2%) e o -cariofileno (13,2%) e o dos rizomas, o -pineno (41,5%), o 1,8-cineol (23,6%) e o -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 obser...

Chemical composition and antibacterial, antifungal, allelopathic and acetylcholinesterase inhibitory activities of cassumunar‐ginger

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Allelopathy of Aromatic Species on the Germination of Cereus jamacaru DC. subsp. jamacaru (Cactaceae)

“…For M. suavoelens, the allelopathic action may be attributed to a synergistic action from the β-Caryophyllene (18.57%), sabinene (15.99%) and spatulenol (11.09%) secondary constituents. In the study by Miranda, Cardoso, Carvalho, Figueiredo and Andrade (2015), β-caryophyllene constituted 13.2% of the Hedychium coronarium J. Koenig (lírio-do-brejo) EO and showed relatively low negative allelopathic effects on Lactuca sativa L. (lettuce) seeds., which are sensitive to allelochemicals. However, this chemical component needs other components to act on seed germination.…”

Chemical Composition of Ambrosia trifida Essential Oil and Phytotoxic Effect on Other Plants

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