Cristina Peitz de Lima

Phytochemical constituents and preliminary toxicity evaluation of leaves from Rourea induta Planch. (Connaraceae)

Most active plants are toxic at high doses and it is therefore important to investigate the preliminary toxicity of plant extracts. The Rourea induta species is a potential drug with no phytochemical or biological studies registered in the literature. Thus, a phytochemical study and a toxicity analysis of the ethanolic extract obtained from the leaves of Rourea induta Planch., Connaraceae, was run. A long chain hydrocarbon, n-tetracosane, and four flavonoids were identified: quercetin, and three glycosylated derivates, quercetin-3-O-α-arabinofuranoside, quercetin-3-O-β-xyloside and quercetin-3-O-β-galactoside. This is the first time these have been isolated in this species. The structures were elucidated by 13C NMR, 1H NMR, UV and IR spectroscopy. The toxicity evaluation of extracts was performed by the brine shrimp method and determination of hemolytic activity. The samples demonstrated no toxic potential by the analyzed methods.

Efeito alelopático e toxicidade frente à Artemia salina Leach dos extatos do fruto de Euterpe edulis Martius

Alelopatia e um processo envolvendo metabolitos secundarios produzidos por plantas que infl uenciam o crescimento e desenvolvimento de sistemas agricolas. Devido a toxicidade dos herbicidas sinteticos para o meio ambiente e para a saude humana tem-se aumentado o interesse na exploracao da alelopatia como uma alternativa para o controle de plantas daninhas. O presente trabalho avaliou efeito dos extratos dos frutos de Euterpe edulis Martius sobre o desenvolvimento de cipselas e plântulas de Lactuca sativa Linne, foram determinados o indice de velocidade de germinacao, o crescimento da radicula e do hipocotilo. Para a avaliacao da toxicidade dos extratos foi realizado o ensaio de toxicidade frente ao microcrustaceo Artemia salina Leach determinando-se a CL50 e percentual de mortalidade. A fracao remanescente demonstrou efeito alelopatico, pois todas as concentracoes alteraram os valores do indice de velocidade de germinacao e as concentracoes de 0,2 e 0,4 mg inibiram tanto o crescimento da radicula quanto o crescimento do hipocotilo. No ensaio de toxicidade todos os extratos apresentaram CL50 superior a 1000 ppm e 0% de mortalidade das artemias, indicando a nao toxicidade dos extratos.

Antibacterial, allelopathic and antioxidant activity of extracts and compounds from Rourea induta Planch. (Connaraceae)

Article history: Received on: 08/08/2012 Revised on: 24/08/2012 Accepted on:05/08/2012 Available online: 28/09/2012 This study evaluated some biological activities of the leaves from Rourea induta Planch., Connaraceae. Fractions of the ethanolic extract from leaves of this species were obtained by liquid/liquid partition and their antibacterial, allelophatic and antioxidant activities were analyzed. By the agar diffusion method the ethyl acetate, chloroform fractions and hyperin showed antimicrobial activity against Staphylococcus epidermidis with an inhibition halo of 15.0, 12.3 and 9.3 mm respectively, and Staphylococcus aureus with 7.6 mm for the fractions. For antioxidant activity all samples have demonstrated a significant potential, especially the chloroform, ethyl acetate fractions and the hyperin which IC50 were, 5.33 ±0.19; 3.21 ± 0.00 and 3.89 ± 0,02 respectively. This result is close to the standards vitamin C and rutin. In the allelopathic activity the hexane fraction at 0.8 mg and 0.4 mg, inhibited 33.24% and 20.54% the hipocotyl’s growth of Lactuca sativa seeds, and the compound tetracosane inhibited 18.05% the hipocotyl’s growth at 0.4 mg. The obtained results stimulate the continuity of this study.

Croton argenteus preparation inhibits initial growth, mitochondrial respiration and increase the oxidative stress from Senna occidentalis seedlings

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.

Polygala extraaxillaris: Estresse em Brachiaria decumbens Mediado por Óleos Voláteis

ABSTRACT - The volatile oils extracted from the roots of Polygala extraaxillaris were analyzedto assess whether they increase oxidative stress in Brachiaria decumbens var. Piata, as well asto assess their effect on cellular division and cytotoxicity in laboratory. Six concentrationswere used (0%, 0.35%, 0.65%, 1.25%, 0.65%, and 5.0%) with four repetitions of 25 seeds. Thesubstance 1-(2-hydroxyphenyl) - ethanone was identified as the major constituent of thevolatile oils. The results showed that the highest concentrations of the oils resulted in anincrease in the oxidative stress in B. decumbens , as well as alteration in germination andgrowth, with a consequent reduction in the process of cellular division, causing changes inthe growth standard and antioxidant defense. Keywords: reactive oxygen species, antioxidant enzymes, plant defense, signal grass. RESUMO - Os oleos volateis extraidos das raizes de Polygala extraaxillaris foram analisadospara avaliar se aumentam o estresse oxidativo em