RESUMO
Senna ocidentalis is a weed, native to Brazil, considered to infest crops and plantations, and is responsible for yield losses of several crops, particularly soybean. The aim of this work was to evaluate if the Croton argenteus extract and fractions possess phytotoxic activity on S. ocidentalis. The crude ethanolic extract (CEE) and its hexanic (HF), chloroformic (CLF) and ethyl acetate (EAF) fractions were tested in germination, growth, oxidative stress increase, Adenosine triphosphate, L-malate and succinate synthesis. The crude extract and its fractions slowed down the germination of S. ocidentalis and decreased the final percentage of germination. Oxidative stress was also increased in the seedlings, by an increase of catalase, peroxidase, superoxide dismutase, glutathione reductase and lipid peroxidation; and it became clear that the ethyl acetate fraction was more phytotoxic. The results indicate that the crude extract and fractions of C. argenteus compromise the mitochondrial energy metabolism, by the inhibition of mitochondrial ATP production, with a decrease in the production of L-malate and succinate. The ethyl acetate fraction of C. argenteus showed high activity on germination and growth, and these effects take place by means of mitochondrial metabolism alterations and increase the oxidative stress, leading the seedling death.
Assuntos
Croton/química , Mitocôndrias/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Extratos Vegetais/farmacologia , Senna/efeitos dos fármacos , Croton/classificação , Germinação/efeitos dos fármacos , Peroxidação de Lipídeos/efeitos dos fármacos , Mitocôndrias/fisiologia , Plântula/efeitos dos fármacos , Plântula/crescimento & desenvolvimento , Senna/crescimento & desenvolvimentoRESUMO
A procura por novos agentes antimicrobianos a partir de plantas vem sendo intensificada e não existem estudos direcionados à avaliação da atividade antimicrobiana de C. jamacaru frente a microrganismos prejudiciais ao homem. Em vista disso, avaliou-se o efeito antimicrobiano do extrato bruto etanólico do lenho (EBLE) e do córtex (EBCO) desta espécie frente a colônias puras de oito microrganismos patogênicos. Neste estudo foram utilizados os métodos difusão em ágar (meio sólido) e CIM (concentração inibitória mínima). Os resultados obtidos neste ensaio preliminar mostraram que EBCO apresentou atividade antimicrobiana mais pronunciada que EBCE e que os microrganismos cujo crescimento foi mais influenciado por EBCO foram Streptococcus epidermidis, Staphylococcus aureus, Pseudomonas aeruginosa e Escherichia coli.
The search for new antibiotic agents from plants is growing, and no study regarding the activity of C. jamacaru pathological microorganisms has been carried out. This research evaluates the antibiotic effect of crude ethanolic extracts of the cortex (EBCO) and wood (EBLE) of the species over eight microorganisms. Two methods were used: agar diffusion and MIC (minimal inhibitory concentration). EBCO showed better inhibition results than EBLE. Streptococcus epidermidis, Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli are the microorganisms that were better inhibited by EBCO.