ABSTRACT
The prophylactic and therapeutic arsenal against malaria is quite restricted and all the antimalarials currently in use have limitations. Thus, there is a need to investigate medicinal plants in the search for phytochemicals which can be developed into drugs. In our investigation, essential oils (EOs) were obtained from Vanillosmopsis arborea (Gardner) Baker, Lippia sidoides Cham. and Croton zehntneri Pax & K. Hoffm., aromatic plants abundant in northeastern Brazil, which are found in the caatinga region and are used in traditional medicine. The chemical composition of these EOs was characterized by GC-MS, and monoterpenes and sesquiterpenes were well represented. We assessed the in vitro activity of these EOs and also individual EO chemical components against the human malaria parasite Plasmodium falciparum (K1 strain) and the in vivo activity of EOs in mice infected with Plasmodium berghei. The acute toxicity of these oils was assessed in healthy mice and in vitro cytotoxicity was determined at different concentrations against HeLa cells and mice macrophages. The EO of V. Arborea was partially active only when using the subcutaneous route (inhibited from 33 up to 47 %). In relation to the EOs, L. sidoides and C. zehntneri were active only by the oral route (per gavage) and partially inhibited the growth of P. berghei from 43 up to 55 % and showed good activity against P. falciparum in vitro (IC (50) = 7.00, 10.50, and 15.20 µg/mL, respectively). Individual EO constituents α-bisabolol, estragole, and thymol also exhibited good activity against P. falciparum (IC (50) = 5.00, 30.70, and 4.50 µg/mL, respectively). This is the first study showing evidence for the antimalarial activity of these species from northeastern Brazil and the low toxicity of their EOs.
Subject(s)
Antimalarials/administration & dosage , Asteraceae/chemistry , Croton/chemistry , Lippia/chemistry , Malaria, Falciparum/drug therapy , Oils, Volatile/administration & dosage , Phytotherapy , Administration, Oral , Allylbenzene Derivatives , Animals , Anisoles/administration & dosage , Brazil , HeLa Cells/drug effects , Humans , Infusions, Subcutaneous , Mice , Monocyclic Sesquiterpenes , Plant Leaves/chemistry , Plant Preparations/administration & dosage , Plant Stems/chemistry , Plants, Medicinal/chemistry , Plasmodium berghei/drug effects , Plasmodium falciparum/drug effects , Sesquiterpenes/administration & dosage , Thymol/administration & dosageABSTRACT
Tendo em vista que bactérias resistentes a antimicrobianos representam um desafi o no tratamento de infecções, é notória a necessidade de encontrar novas substâncias com propriedades antimicrobianas para serem utilizadas no combate a esses microrganismos. Este trabalho relataa avaliação da atividade antibacteriana, toxicidade e identifi cação dos componentes químicos do óleo essencial de Croton zehntneri (variedade estragol), planta utilizada na medicina popular como calmante e estimulante do apetite. A atividade antimicrobiana e a concentração inibitória mínima (CIM) foram determinadas pelo método de difusão em discos. A avaliação da toxicidade foi realizada frente à Artemia salina com resultado considerado ativo (CL50 < 100 μg/mL). O óleo essencial das folhas apresentou atividade antibacteriana frente a todas as bactérias testadas exceto contra Salmonella typhimurium, sendo o melhor resultado frente a Shigella fl exneri com CIM de 50 μg/mL. A análise da composição química foi obtida por cromatografi a gasosa acoplada aespectrometria de massa (CG/EM) e permitiu identifi car um total de 97,4% dos componentes, com presença majoritária de estragol (76,8%). A presença de tal constituinte nos impulsiona a realização de estudos com outras bactérias, já que o estragol foi anteriormente relatado como sendo responsável por atividades antibacterianas.
Observing that bacteria resistant to antimicrobials represent a challenge in the treatment of infections, it is notoriousthe need of fi nding new substances with antimicrobial features to be used in the fi ght against these microorganisms. This work relates the evaluation of the antibacterial activity, toxicity andidentifi cation of the chemical components of the essential oil of Croton zehntneri (variety estragol), plant used in the popular medicine as tranquilizer and appetite stimulant. The antimicrobialactivity and minimum inhibitory concentration (MIC) were determined by the method of diffusion in discs. The evaluation of the toxicity was held through brine shrimp test with results considered active (LC50 < 100 μg/mL). The essential oil of leaves presented antibacterial activity with all the bacteria tested except with Salmonlla typhimurium, being the best result with the Shigella fl exneri with MIC of 50 μg/mL. The analysis of the chemical composition was obtained by gas chromatography coupled to mass spectrometry (GC/MS) and permitted to identify a total of 97.4 % of the components, with major presence of estragol (76.8%). The presence of the latter drives us to studies with other bacteria, as the estragol was previously reported as being responsible forantibacterial activities.
