ABSTRACT
The aim of this study was to evaluate the antibacterial activity of nanoemulsions of Baccharis dracunculifolia essential oil. The volatile compounds of the essential oil were identified using gas chromatography-mass spectrometry. The properties of the nanoemulsions (droplet size, polydispersity index, pH, and electrical conductivity) were determined. The antibacterial activities of the essential oil and its nanoemulsions were evaluated using MIC, MBC, and disk diffusion. The microorganisms used were: Gram-positive bacteria (Staphylococcus aureus ATCC 25923, Bacillus cereus ATCC 14579, Streptococcus mutans ATCC 25175, and Enterococcus faecalis ATCC 29212) and Gram-negative bacteria (Pseudomonas aeruginosa ATCC 27853, Klebsiella pneumoniae ATCC BAA-1706, Salmonella enterica ATCC 14028, and Escherichia coli ATCC 25922). The major volatile compounds of the B. dracunculifolia essential oil were limonene (19.36%), (E)-nerolidol (12.75%), bicyclogermacrene (10.76%), and ß-pinene (9.60%). The nanoemulsions had a mean droplet size between 13.14 and 56.84 nm. The nanoemulsions presented lower and statistically significant MIC values compared to the essential oil, indicating enhancement of the bacteriostatic action. The disk diffusion method showed that both the nanoemulsions and the essential oil presented inhibition zones only for Gram-positive bacteria, while there were no results against Gram-negative bacteria, indicating that B. dracunculifolia essential oil has a better antimicrobial effect on Gram-positive microorganisms.
ABSTRACT
The medicinal plant Maytenus ilicifolia is a commonly used phytomedicine for the treatment of gastritis. The high dose required and low density of these extracts make necessary a daily intake of several capsules, hindering adherence to the medication. The purpose of this work was to develop a suitable dosage form for the administration of Maytenus ilicifolia using effervescent granules. A 23 factorial design was used to study the physical characteristics of the granules (particle size distribution, repose angle, Carr index, scanning electron microscopy and disintegration time). Moisture stability was also determined. According to the experimental design, granule size is the most important factor in determining the flow characteristics of effervescent granules. In turn, the disintegration time is controlled by the content of sodium bicarbonate present in the effervescent mixture as well as the granule size. The stability of formulations when exposed to moisture is strongly influenced by the percentage of effervescent mixture present in the vegetal granules. Precautions in handling and storage should be taken to ensure the stability of these preparations. The effervescent granules produced from Maytenus ilicifolia met the pharmacopoeial quality parameters, with appropriate mechanical and physical characteristics and proved to be a promising vehicle for plant extracts.
A planta medicinal Maytenus ilicifolia é comumente empregada como fitoterápico no tratamento da gastrite. As elevadas doses requeridas e a baixa densidade dos extratos dessa planta levam à ingestão diária de várias cápsulas do medicamento, dificultando a adesão ao tratamento. A proposta desse trabalho foi desenvolver uma forma farmacêutica adequada para administração de Maytenus ilicifolia usando granulados efervescentes. Um desenho fatorial 23 foi empregado para estudar as características físicas dos granulados (distribuição dos tamanhos de partícula, ângulo de repouso, índice de Carr, microscopia eletrônica de varredura e tempo de desintegração). A higroscopicidade das preparações também foi estudada. De acordo com o desenho experimental, o tamanho de partícula é o fator mais importante para a determinação das características de fluxo dos granulados efervescentes. Em contrapartida, o tempo de desintegração é controlado pelo conteúdo de bicarbonato de sódio presente na mistura efervescente, assim como pelo tamanho do granulado. A estabilidade das formulações quando expostas à umidade é fortemente influenciada pelo percentual de mistura efervescente presente nos granulados. Precauções de manipulação e armazenamento devem ser tomadas para garantir a estabilidade dessas preparações. Os granulados efervescentes produzidos com Maytenus ilicifolia cumprem os requisitos farmacopeicos de qualidade, com adequadas características físicas e mecânicas, provando ser um veículo promissor para extratos vegetais.
