This study evaluated the toxicity and antimicrobial activity in the face of Escherichia coli and Staphylococcus aureus of essential oils of Pimenta dioica Lindl. and Citrus sinensis L. The essential oils (EOs) were extracted by hydrodistillation, with chemical characterization by gas chromatography coupled and mass spectrometry (GC-MS). Physicochemical parameters were determined according to the Brazilian Pharmacopeia. The toxicity test followed the bioassay with Artemia salina Leach, the EOs approved in this assay followed to evaluate its biological properties. The antimicrobial activity followed the methodology described by the Clinical and Laboratory Standards Institute using the Disc Diffusion Method, Broth Dilution for Minimum Inhibitory Concentration (MIC) and subsequent minimum bactericide concentration for to evaluate the action of EOs against E. coli and S. aureus. Both EOs showed low toxicity, and thus were evaluated for the biological antimicrobial properties. Both EOs presented bactericidal potential against the microorganisms tested, showing satisfactory results for their action. The results indicate that the evaluated EOs are composed of substances that provide and encourage their application due to their potential for antimicrobial biological activity.

This study aimed to evaluate the larvicidal activity of essential oil microparticles (EO) of Melissa officinalis L. against Aedes aegypti. The leaves of M. officinalis were collected in the municipality of São José de Ribamar, Maranhão, Brazil, later dried, crushed and ground. 90g of the dried leaves were used to obtain the EO by the hydrodistillation method. For the synthesis of microencapsulated EO, 60g of sodium alginate (2.5% m/v) was added to the mixture of 15g of Tween 20 with 6g of EO. The mixture was homogenized and drips over CaCl2 5% m/v solution for the hardening of particles via crosslinking. The microparticles were washed with distilled water in filter and dried at 35ºC/24h and 15 days at tamb (30ºC). The eggs of Aedes aegypti were collected at the Federal University of Maranhão by the ovitrampas method. The larvae that hatched were fed until they reached the fourth instar. Groups of larvae (n=20) were submitted to solutions of EO and microparticles of 10-90 mg/L . After 24 h, live and dead larvae were counted and LC50 was calculated by the Reed&Muench method, using Cheng's criterion for classification of active potential. All larvae presented mortality in all concentrations tested. The LC50 obtained for the EO was 40.60 mg/L and for the microparticles 22.10 mg/L, both classified as active according to the adopted criterion, but it is observed that the microparticles increased the larvicidal potential of the EO. Through the results obtained, it is concluded that the microparticles formulated with the EO proved to be efficient in the face of the larvae of Aedes aegypti, being interesting and important in controlling and combating the mosquito that transmits dengue.

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This study evaluated the antimicrobial, antioxidant and toxicity activity of essential oils (EOs) of Hymenaea courbaril L. var. courbaril bark and Syzygium cumini (L.) Skeels leaves. The EOs were extracted by hydrodistillation and chemically characterized by gas chromatography coupled to mass spectrometry (GC/MS). The ABTS and DPPH assay were used to evaluate antioxidant activity. For the toxicity assay, lethality was evaluated against Artemia salina Leach. For the antimicrobial assay, the method of Disc Diffusion and Dilution in Broth was applied to obtain the minimum inhibitory concentration and minimum bactericidal. The major constituent of the EO of H. courbaril was β-ocimene (23.33%) and the EO of S. cumini was isocaryophyllene (18.01%). Both OE showed relevant antioxidant activity and low toxicity against Artemia salina. The EOs showed bactericidal activity against E. coli, S. aureus, P. aeruginosa, Salmonella sp., B. cereus and P. mirabilis. The results obtained are encouraged by the potential use of the OE's studied in the control and fight of pathogenic microorganisms.

The present study evaluated the toxicity and larvicidal activity of essential oil (EO) of Alpinia zerumbet leaves. The (EO) was extracted by hydrodistillation at 100°C for 3h and the physicochemical parameters were determined using the Brazilian Pharmacopoeia. Toxicity was performed through the bioassay of Artemia salina Leach, then larvicidal activity was evaluated against Aedes aegypti. LC50 was calculated for toxicity and larvicidal activity against mosquito larvae based on the Reed-Muench method. The EO was classified for toxicity and the Dolabela criterion was used. In the toxicity bioassay, LC50 321.15 mg L-1 was classified as nontoxic. Larvicidal activity against Aedes aegypti showed 50.70 mg L-1 according to EO. Total phenolics resulted in 513.574 mg EAT g-1. The EO presented satisfactory results against the microorganisms tested, revealing its efficiency in combating and controlling pathogenic microorganisms and larvicides.

This study evaluated the molluscicidal activity of essential oils (EOs) of Syzygium cumini L. and Hymenaea courbaril L. Hydrodistillation was used to extract the EOs. The chemical characterization was performed by Gas Chromatography coupled to mass spectrometry. The bioassay of Artemia salina Leach was used for the toxicity test. The molluscicidal assay tested concentrations of 10-80 mg L-1 of the EOs against Biomphalaria glabrata. The major constituent of The EO of S. cumini was isokaryophyllene and H. courbaril the Germacreno-D. The toxicity assay classified The EOs as nontoxic with LC50 412.10 mg L-1 for S. cumini and LC50 354.80 mg L-1 for H. courbaril. The molluscicidal assay purchased LC50 44.76/ LC90 77.20 for S. cumini and LC50 37.34 mg L-1/ LC90 73.24 mg L-1 for H. courbaril. The results showed that both EOs can be used as natural molluscicides in combating the snail Biomphalaria glabrata.

Objetivou-se avaliar a influência da temperatura da secagem das folhas de Bixa orellana L. nas propriedades biologicas dos óleos essenciais (OE’s) obtidos. O material vegetal foi coletado e submetido a estufa convectiva de ar em temperaturas entre 35-55 °C. Os OE's foram obtidos através de hidrodestilação. O ensaio antimicrobiano foi realizado a partir do Método de Difusão de Disco frente a Staphylococcus aureus e Escherichia coli. Para o bioensaio de toxicidade avaliou-se a letalidade dos OE’s frente a Artemia salina.  Foram observadas diferenças significativas nas propriedades dos OE's. A temperatura de 45 °C permitiu obter a ação bactericida mais eficiente frente aos microrganismos testados e a toxicidade também foi verificada para o OE obtido nesta temperatura. Este estudo conclui através das atividades analisadas que a temperatura de secagem influencia nas propriedades dos OE's e a temperatura de 45° é afirmada como a mais indicada para B. orellana em virtude do melhor desempenho das propriedades tanto no ensaio antimicrobiano quanto de toxicidade.

This study aimed to evaluate the chemical profile and larvicidal activity of essential oil (EO) extracted from the leaves of Pimenta dioica L. in front of the larvae of the Aedes aegypti mosquito. The EO was extracted by hydrodistillation, with chemical characterization through coupled Gas Chromatography and mass spectrometry (GC-MS). The physicochemical parameters were determined according to the methods described in the Brazilian Pharmacopoeia. The toxicity assay evaluated the lethality of EO against Aedes aegypti. CL50 was calculated for EO action against Aedes aegypti larvae using the Probit method. The larvicidal activity of OE presented mortality at concentrations of 10 to 100 mg L-1 and LC50 of 26,91 mg L-1. The results indicate that the evaluated EO is composed of substances that have a good larvicidal effect against Aedes aegypti,demonstrating its efficiency in combating and controlling the Aedes aegypti mosquito.