Abstract The present work aimed to isolate secondary metabolites from Myrcia insularis Gardner (Myrtaceae) wood and to evaluate the anti-Candida activity and further extracts obtained by partition and the respective main isolated compounds. Wood was collected in a Seasonal Semideciduous Forest remnant of the Atlantic Forest of northern Rio de Janeiro State, Brazil. Chromatographic and spectrographic techniques were used to isolate and identify secondary metabolites. Methanol extract inhibited the growth of Candida buinensis and Candida tropicalis, with inhibition being approximately 82% for the latter. The main compound isolated from the ethyl acetate partitions was arjunolic acid, a triterpene. The antimicrobial activity was first observed with the wood metabolites of M. insularis adds to our understanding of the antifungal properties of this species and other species within the Myrtaceae family, including the presence of arjunolic acid, which may play a role in this activity.

Plantas exsudam uma variedade de substâncias através de sua superfície, especialmente de raízes e sementes germinantes. Algumas dessas substâncias parecem apresentar atividades inibitórias contra determinados patógenos vegetais. Proteínas transportadoras de lipídeos (LTPs) são peptídeos catiônicos básicos de 9 kDa, ricos em cisteína e que possuem a função de proteção de plantas contra infecções microbianas. O objetivo deste trabalho foi o isolamento e a determinação da massa molecular de uma LTP presente em exsudatos de sementes embebidas de feijão-de-corda (Vigna unguiculata). Para indução da exsudação, 50 sementes foram submersas em 50 mL de tampão acetato de sódio, 100 mmol.L-1, pH 4,5 e mantidas a 30 ºC sob agitação por 24 h. O exsudato foi submetido à precipitação por sulfato de amônio e o precipitado formado entre 0 e 70 % de saturação foi dialisado, recuperado por liofilização e submetido a cromatografias para a purificação e determinação da massa molecular da LTP. Todas as etapas foram monitoradas por eletroforese em gel de tricina e por Western blotting, usando-se anticorpo produzido contra LTP isolada de sementes de feijão-de-corda. A proteína transportadora de lipídeo purificada apresentou massa molecular de 9 kDa.

Plants exude a variety of substances through their surface especially of roots and germinating seeds. Some of these released compounds seem to have an inhibitory action against certain pathogens. Lipid transfer proteins (LTPs) are 9 kDa cysteine-rich cationic peptides and are thought to play a role in the protection of plants against microbial infections. The aim of this work was to isolate and determine the molecular mass of a LTP present in the exudates of imbibed cowpea seeds. For exudation induction, 50 seeds were submerged in 50 mL sterile 100 mmol.L-1 Na-acetate buffer, pH 4.5 and shaken at 30 ºC for 24 h. The resulting exudate was subjected to ammonium sulphate fractionation and the pellet formed between 0 and 70 % saturation was dialysed and recovered by freeze drying. Further purification steps were carried out using chromatographic methods and the molecular mass of the LTP determined. All of these steps were monitored by SDS-Tricine gel electrophoresis and Western blotting using an anti-LTP serum. The purified LTP showed a relative molecular mass of 9 kDa.

Análise do látex de Manihot glaziovii mostrou a presença de várias atividades enzimáticas e inibitórias. O látex apresentou também um efeito inibitório sobre o desenvolvimento do gorgulho/caruncho do feijão-de-corda (Callosobruchus maculatus) em um sistema de sementes artificiais e sobre o desenvolvimento, em um ensaio in vitro, dos fungos fitopatogênicos Colletotrichum gloesporioides, Fusarium solani e Macrophomina phaseolina. Esses resultados sugerem a presença de substâncias, algumas delas de natureza protéica, envolvidas em mecanismos de defesa de plantas neste exsudato.

Analysis of the latex from Manihot glaziovii showed the presence of various enzymatic and inhibitory activities. The latex also presented an inhibitory effect on the development of cowpea weevil (Callosobruchus maculatus) in an artificial seed system and on the development, in an in vitro assay, of phytopathogenic fungi Colletotrichum gloesporioides, Fusarium solani and Macrophomina phaseolina. These results suggest the presence of substances, some of them of protein nature, involved in plant defense mechanisms in this exudation product.