Effect of hydroxyamines derived from lapachol and norlachol against Staphylococcus aureus strains carrying the NorA efflux pump.

Isolated substances and those organically synthesized have stood out over the years for their therapeutic properties, including their antibacterial activity. These compounds may be an alternative to the production of new antibiotics or may have the ability to potentiate the action of preexisting ones. In this context, the objective of this study was to evaluate the in vitro antibacterial and efflux pump inhibitory activity of hydroxyamines derived from lapachol and norlachol, more specifically the compounds 2-(2-Hydroxyethylamino)-3-(3-methyl-2-butenyl)-1,4 dihydro-1,4-naphthalenedione, 2-(2-Hydroxyethylamino)-3-(2-methyl-propenyl)[1,4]naphthoquinone and 2-(3-Hydroxypropylamino)-3-(3-methyl-2-butenyl)-[1,4]naphthoquinone, against Staphylococcus aureus strains carrying the NorA efflux pump mechanism. The substances were synthesized from 2-hydroxy-quinones, lapachol and nor-lapachol, obtaining the corresponding 2-methoxylated derivatives via dimethyl sulfate alkylation in a basic medium, which then reacted chemoselectively with 2-ethanolamine and 3-propanolamine to form the corresponding amino alcohols. All three molecules underwent a virtual structure-based analysis (docking). The antibacterial activity of the substances was measured by determining their Minimum Inhibitory Concentration (MIC) and a microdilution assay was performed to verify efflux pump inhibition using the substances at a sub-inhibitory concentration. The results were subjected to statistical analysis using an analysis of variance (ANOVA) followed by Bonferroni's post hoc test. The substances obtained MIC values ≥1024 µg/mL, however, a significant reduction of their MICs was observed when the substances were associated with norfloxacin and ethidium bromide, with this effect being attributed to efflux pump inhibition. Following a virtual analysis based on its structure (docking), information regarding the affinity of new ligands for the ABC efflux pump were observed, thus contributing to the understanding of their mechanism of molecular interactions and the discovery of functional ligands associated with a reduction in bacterial resistance.

In silico evaluation of the antibacterial and modulatory activity of lapachol and nor-lapachol derivates.

The aim of this research was to investigate the pharmacological properties of 2-(2-hydroxyethylamine)-3-(3-methyl-2-butenyl)-1,4-dihydro-1,4-naphthalenedione, 2-(2-hydroxy-ethylamine)-3-(2-methyl-propenyl)-[1,4]naphthoquinone and 2-(3-hydroxy-propylamine)-3-(3-methyl-2-butenyl)-[1,4]naphthoquinone using computational prediction models, in addition to evaluating the in vitro antibacterial and modulatory activity of these compounds against bacterial ATCC strains and clinical isolates. The substances were synthesized from 2-hydroxy-quinones, lapachol and nor-lapachol obtaining the corresponding 2-methoxylated derivatives via dimethyl sulfate alkylation in a basic medium, these then reacted chemoselectively with 2-ethanolamine and 3-propanolamine to form the corresponding amino alcohols. The antibacterial activity and modulatory activity of the substances were assayed by broth microdilution method to determine the Minimum Inhibitory Concentration (MIC). The molecular structures were analyzed using the ChEMBL database to predict possible pharmacological targets, which pointed to the molecule 2- (2-hydroxy-ethylamine)-3-(2-methyl-propenyl)-[1,4]naphthoquinone as a probable antibacterial agent for the proteins Replicative DNA helicase and RecA. The compounds had a low molecular weight and a small number of rotatable bonds. The MICs of the substances were not clinically significant, however, the association with gentamicin and amikacin reduced the MICs of these antibiotics. In conclusion, the combination of these substances with aminoglycosides may be a therapeutic alternative to bacterial resistance and the reduction of side effects.

Vigilância pós-comercialização da Aguardente Alemã® (Operculina macrocarpa e Convolvulus scammonea) / Post-marketing surveillance of the Aguardente Alemã® (Operculina macrocarpa and Convolvulus scammonea)

A Aguardente Alemã (AA), produzida a partir dos extratos das raízes de Operculina macrocarpa e Convolvulus scammonia, conhecida, também, como “jalapa composta”, é indicadacomo laxante, mas é utilizada, popularmente, para as mais variadas patologias. Este trabalho objetivou delinear o perfi l do usuário desse fi toterápico, a forma de administração e as principais indicações de uso relatadas pelo usuário, utilizando, para isto, um questionário aplicado à população (n = 125) no momento da dispensação do produto em farmácias de Fortaleza, Ceará. Os usuários eram, na sua maioria, mulheres, com idade de 41 a 60 anos. A administração de AA era feita, em geral, com uma colher de chá (5 mL; 46,4%), uma vez por dia (87%), sem um horário fi xo de tomada; administrando com chá ou água, prioritariamente. A população referiuusar AA, principalmente, para problemas circulatórios (63%) e cefaléia (13,1%). A atividade purgativa, rotulada na formulação do produto comercializado, foi pouco referida. Desta feita, nossos resultados subsidiam importantes informações para o processo de certifi cação de AA junto às agências regulatórias e enfatizam a necessidade de mais estudos de vigilância póscomercialização, para a garantia do uso racional do produto pelo usuário.

The “Aguardente Alem㔠(AA), produced from extracts of the roots of Operculina macrocarpa and Convolvulus scammonea, also known as “composed jalapa”, is indicated as laxative, but it is used, popularly, for several diseases. Our objective was to delineate the user profi le of this herbal medicine, the way it is managed and the main use indications referred by users through a questionnaire applied to the population(n = 125) at the moment of the AA dispensing in community pharmacies of Fortaleza, Ceará. The users were mainly women, aged between 41 and 60 years. The administration of AA was generally done with a tea spoon (5 mL; 46.4%), once per day (87%), without an established time for taking; managing it with tea and water, principally. It was indicated by the population for using in diseases as circulatory problems (63%) and migraine (13.1%). The laxative activity, labeled in the formulation of the product, was poorly related. Thus, our results provide important information for the certifi cation process of AA to the regulatory agencies and emphasize thenecessity of more studies of post-marketing surveillance for the guarantee of the rational use of this product to the user.

Pilocarpine-induced seizures in adult rats: monoamine content and muscarinic and dopaminergic receptor changes in the striatum.

High doses of the muscarinic cholinergic agonist pilocarpine are a useful model for investigation of the essential mechanisms for seizure generation and spread in rodents. Pilocarpine (400 mg/kg; subcutaneously) was administered in 2-month-old female rats, and the content of striatum monoamines and (M(1)+M(2)) muscarinic and D(2) dopaminergic receptors was measured in the acute period. All treated animals showed peripheral cholinergic signs, stereotyped and clonic movements, tremors, seizures and the percentage mortality was approximately 63%. High performance liquid chromatography determinations, performed 24 h later, showed a decrease of striatal levels of dopamine, dihydroxyphenylacetic acid, 4-hydroxy-3-methoxy-phenylacetic acid and 5-hydroxytryptamine. Pilocarpine treatment induced downregulation of (M(1)+M(2)) muscarinic receptors and reduced the dissociation constants of (M(1)+M(2)) muscarinic and D(2) dopaminergic receptors, suggesting that these systems exert opposite effects on the regulation of convulsive activity. These and other important neurochemical changes found in the course of establishment of an epileptic focus can be observed after status epilepticus induced by pilocarpine.

Attenuating effects of melatonin on pilocarpine-induced seizures in rats.

Daily melatonin (10-50 mg/kg, i.p.) treatment at 08.30 h or 17.00 h for 1 week of female rats (2-months-old) increased the latency to the appearance of the first convulsion in the pilocarpine-induced seizure model. Other behavior parameters remained unaltered. The anticonvulsant effect of melatonin seemed to be more intense at the light-dark transition. Moreover, the effect of repeated melatonin treatment was also age-related, since it showed a lower threshold in 2-month-old than in 21-day-old rats, and the acute treatment was not efficient. [3H]N-methylscopolamine binding was unaltered in the hippocampus and striatum of adult rats after the association of melatonin and pilocarpine. While muscarinic binding was unaltered in adult rats, it increased in the hippocampus of young rats in the presence of melatonin (50 mg/kg) and pilocarpine, and did not change in the striatum. Melatonin partially recovered [3H]GABA binding in the hippocampus in the presence of pilocarpine-induced seizures, and intensified pilocarpine effects in the striatum of adult rats.