Atividade antimicrobiana "in vitro" e determinação da concentração inibitória mínina (CIM) de fitoconstituintes e produtos sintéticos sobre bactérias e fungos leveduriformes

Abstract

RESUMO:Diante da problemática da resistência microbiana as pesquisas apontam para o uso de novos antibióticos que sejam efi cazes ante os patógenos emergentes. Este trabalho objetiva testar frente a bactérias gram-positivas (Staphylococcus aureus), bactérias gram-negativas (Escherichia coli e Pseudomonas aeruginosa) e fungos leveduriformes (Candida albicans), a atividade antimicrobiana e a concentração inibitória mínima (CIM) de fi toconstituintes de Ocotea duckei Vattimo, do lapachol, seus derivados semi-sintéticos, -lapachona, -nor-lapachona, -lapachona, -nor-lapachona, -3-iodo-lapachona e -3-iodo-lapachona, assim como 07 derivados nitrogenados obtidos a partir do lapachol por semi-síntese e de imidas cíclicas similares ao alcalóide fi lantimida. Os resultados obtidos estimulam o aprofundamento dos estudos para algumas dessas substâncias a exemplo do lapachol e seus análogos que demonstraram atividade antimicrobiana, de modo que os produtos que se apresentaram ativos para S. aureus, foram lapachol e o extrato etanólico de Ocotea duckei, para E. coli foi a iangambina e para a Candida albicans foram as imidas. As demais substâncias não apresentaram atividade antimicrobiana para as cepas testadas.Unitermos: Atividade antimicrobiana, fi toconstituintes, produtos de síntese, iangambina, lapachol, bactérias, leveduras.ABSTRACT: "In vitro antimicrobial activity and determination of the minimum inhibitory concentration (MIC) of natural and synthetic compounds against bacteria and leveduriform fungi". Regarding the problem of microbial resistance, the researches point to the use of new antibiotic which can be active against the emergent pathogens. This work aims to test the activity against Gram-positive bacteria (Staphylococcus aureus), Gram-negative bacteria (Escherichia coli e Pseudomonas aeruginosa) and leveduriform fungi (Candida albicans), and also the Minimum Inhibitory Concentration (MIC) of the constituent of Ocotea duckei Vattimo, lapachol and its synthetic derivatives -lapachone, -nor-lapachone, -lapachone, -nor-lapachone, -3-iodinlapachone and -3-iodin-lapachone, as well as seven nitrogenated derivatives of lapachol obtained through semi synthesis. The achieved results stimulate the deepening of the studies for some of theses substances such as lapachol and its analogous which demonstrated antimicrobial activity. The substances which were active against S. aureus, were lapachol and the ethanolic extract of Ocotea duckei Vattimo, against Escherichia coli iangambin and against C. albicans the imides. The other substances did not show any activity against the tested bacteria.

Evaluation of antibacterial activity of "Mangabarana" Austroplenckia populnea Reissek (Celastraceae)

“…Consequently, a great variety of medicinal plants have been investigated to evaluate and validate their real biological activity (Cardoso and Santos, 1948;Kinghorn and Balandrin, 1993;Rao, 1996;Gnan and Demello, 1999;Hernandez et al, 2000;Deena et al, 2000;Cardoso-Lopes et al, 2008). The use of plants and their derivatives for different diseases occurs since the beginning of the humanity (Antunes et al, 2006). With the advances of pharmaceutical industries, mainly after World War II, the use of herbal medicines diminishes in function of the dissemination idea of its inefficiency (Antunes et al, 2006).…”

“…The use of plants and their derivatives for different diseases occurs since the beginning of the humanity (Antunes et al, 2006). With the advances of pharmaceutical industries, mainly after World War II, the use of herbal medicines diminishes in function of the dissemination idea of its inefficiency (Antunes et al, 2006). However, the efficacy and trustworthiness in medicinal plant products have demonstrated the real value of these materials.…”

GC-MS analysis and cardiovascular activity of the essential oil of Ocotea duckei

“…Previous reports on Ocotea duckei described the isolation of alkaloids Silva et al, 2002;Morais et al, 1998a) and lignoids (Morais et al, 1996;Morais et al, 1998b;Morais et al, 1999;Barbosa-Filho et al, 1999). Yangambin, the main lignoid isolated from this species has shown many pharmacological properties, such as: (a) a selective platelet activating factor (PAF) receptor antagonist, observed in several in vitro and in vivo experimental models (Castro-Faria-Neto et al, 1995a,b;Herbert et al, 1997), (b) an effective pharmacological agent against cardiovascular collapse and mortality in endotoxin shock Ribeiro et al, 1996;Araújo et al, 2001), (c) an anti-allergic effect (Serra et al, 1997), (d) increased sleeping time induced by pentobarbital and the blockage of convulsions induced by pentylenotetrazole (Almeida et al, 1995;Pachú et al, 1993), (e) yangambin was not mutagenic when tested using strains of Salmonella typhimurium (Marques et al, 2003), (f) topical treatment of eggs and fi rst instars with yangambin as well as feeding larvae with a yangambin-treated diet resulted in inhibition of postembryonic development, morphological alteration, and oviposition reduction (Cabral et al, 2007a,b), (g) yangambin presented antileishmanial activity against promastigotes forms of L. chagasi and L. amazonensis (Monte-Neto et al, 2007) and antimicrobial activity against Escherichia coli (Antunes et al, 2006). This is the fi rst report of the composition of the essential oils obtained from the fruits, leaves, stem and roots of Ocotea duckei, as well as the pharmacological activity on the cardiovascular system.…”

Antibacterial activity of plant extracts from Brazil against fish pathogenic bacteria

“…A variety of plant species are capable of synthesizing many substances with antibacterial activity. These properties have been described to extracts of many plants found in Brazilian flora (1,16,20). However, to the plants analyzed in this work, there aren't previous studies evaluating this characteristic, except to Schinus terebinthifolia Raddi and Xylosma sp.…”

“…Regarding the problem of microbial resistance, there is an urgent need to establish the rules to the rational use of antibiotics and the discovery of new drugs and alternative therapies to control bacterial diseases. Owing the ability to synthesize many different substances, the plants are one of the top richest sources of new drugs (1,5). Extracts of Brazilian methanolic plants have a high potential as an alternative source of antibacterial compounds (15,16,20,23).…”