Effects of anesthesia with the essential oil of Ocimum gratissimum L. in parameters of fish stress / Efeitos da anestesia com o óleo essencial de Ocimum gratissimum L. em parâmetros de estresse de peixes

RESUMO: The effects of anesthesia with the essential oil of Ocimum gratissimum (EOO) in parameters of stress after handling were investigated in silver catfish (Rhamdia quelen). EOO was obtained from the aerial parts by hydrodistillation. Juveniles were anesthetized with 70 or 300 mg L-1 EOO and submitted to air exposure for 1 minute. The fishes were sampled immediately or transferred to anesthetic-free aquaria until sampling. In the first experiment, juveniles had their blood collected at 0, 1, 4, and 8 h after handling to assay plasma cortisol and blood glucose levels. The unanesthetized animals were restrained manually for blood collection. In the second experiment, water samples of the recovery aquaria were collected to evaluate net ion fluxes at 0 - 4 h and 4 - 8 h. Water and ethanol controls were also performed under the same conditions. The results showed that the cortisol levels did not differ among the treatments. Hyperglycemia was verified in fish exposed to 70 and 300 mg L-1 EOO at 1 h and 4 h after handling. After 8 h, cortisol and glucose concentrations were lower or similar than those from immediately after handling for all treatments. EOO anesthesia prevented Na+ efflux observed in the control groups in both flux periods. There were net Cl- and K+ effluxes at 0 - 4 h and influxes at 4 - 8 h after handling in most treatments, and these fluxes did not differ among the treatments. The results suggest that EOO did not impair stress recovery and did not act as an additional handling stressor in silver catfish.

RESUMO: Os efeitos da anestesia com o óleo essencial de Ocimum gratissimum (EOO) em parâmetros de estresse após manuseio foram investigados em jundiás (Rhamdia quelen). EOO foi obtido a partir das partes aéreas por hidrodestilação. Os juvenis foram anestesiados com 70 ou 300 mg L-1 de EOO e expostos ao ar por 1 minuto. Os peixes foram amostrados imediatamente ou transferidos para aquários sem anestésico até amostragem. No primeiro experimento, os juvenis tiveram seu sangue coletado em 0, 1, 4, e 8 h após manuseio para avaliar os níveis de cortisol e glicemia. Os animais não anestesiados foram contidos manualmente para coleta sanguínea. No segundo experimento, amostras de água foram coletadas do aquário de recuperação dos animais para avaliação do fluxo iônico entre 0 - 4 h e 4 - 8 h. Grupos controles em água e etanol também foram realizados sobre as mesmas condições. Os resultados demonstraram que os níveis de cortisol não diferiram entre os tratamentos. Hiperglicemia foi detectada em peixes expostos a 70 e 300 mg L-1 de EOO em 1 h e 4 h após o manuseio. Após 8 h, os teores de cortisol e glicose foram menores ou similares aqueles imediatamente após o manuseio para todos os tratamentos. A anestesia com EOO preveniu o efluxo de Na+ observado para os grupos controle em ambos os períodos avaliados. Ocorreram efluxos de Cl- and K+ entre 0 - 4 h e influxos entre 4 - 8 h após o manuseio para a maioria dos tratamentos, e estes eventos não diferiram entre os tratamentos. Os resultados sugerem que o EOO não prejudica a recuperação do animal frente ao evento estressor ou atua como estressor adicional ao manuseio em jundiás.

Chemical composition, mechanism of antibacterial action and antioxidant activity of leaf essential oil of Forsythia koreana deciduous shrub

OBJECTIVE@#To identify the chemical constituents of leaf essential oil of Forsythia koreana (F. koreana) and evaluate its effects on bacterial strains.@*METHODS@#The essential oil of leaf of F. koreana was extracted by using hydrodistillation process and the volatile components investigated with the help of gas chromatography coupled with mass spectrometry. The antibacterial study was carried out with the help of agar disc diffusion method, MIC, MBC and viable count. The mode of action was determined with help of potassium ion flux, cellular material release and scanning electron microscopy. The antioxidant activity was determined with the help of 2, 3-diphenyl-2-picrylhydrazyl method, nitric oxide scavenging activity and superoxide anion radical scavenging assay.@*RESULTS@#Total ten compounds were identified as trans-phytol (42.73%), cis-3-hexenol (12.95%), β-linalool (10.68%), trans-2-hexenal (8.86%), trans-2-hexenol (8.86%), myrcenol (3.86%), 4-vinylphenyl acetate (3.86%), (4Z)-4,6-heptadien-1-ol (3.18%), lemonol (2.73%) and benzeneacetaldehyde (2.27%) by gas chromatography coupled with mass spectrometry. The antibacterial study was demonstrated that leaf essential oil of F. koreana act against foodborne and other pathogenic bacteria. The mode of action revealed that this essential oil acted on the cytoplasmic membrane, resulting in loss of integrity and increased permeability. In addition, leaf essential oil of F. koreana was shown to be rich in linalool, which contributes to improved antioxidant activity.@*CONCLUSIONS@#These results show that leaf essential oil of F. koreana has great potential as a natural food preservative, antibacterial and antioxidant agent.

Chemical composition, mechanism of antibacterial action and antioxidant activity of leaf essential oil of Forsythia koreana deciduous shrub

Objective: To identify the chemical constituents of leaf essential oil of Forsythia koreana (F. koreana) and evaluate its effects on bacterial strains. Methods: The essential oil of leaf of F. koreana was extracted by using hydrodistillation process and the volatile components investigated with the help of gas chromatography coupled with mass spectrometry. The antibacterial study was carried out with the help of agar disc diffusion method, MIC, MBC and viable count. The mode of action was determined with help of potassium ion flux, cellular material release and scanning electron microscopy. The antioxidant activity was determined with the help of 2, 3-diphenyl-2-picrylhydrazyl method, nitric oxide scavenging activity and superoxide anion radical scavenging assay. Results: Total ten compounds were identified as trans-phytol (42.73%), cis-3-hexenol (12.95%), β-linalool (10.68%), trans-2-hexenal (8.86%), trans-2-hexenol (8.86%), myrcenol (3.86%), 4-vinylphenyl acetate (3.86%), (4Z)-4,6-heptadien-1-ol (3.18%), lemonol (2.73%) and benzeneacetaldehyde (2.27%) by gas chromatography coupled with mass spectrometry. The antibacterial study was demonstrated that leaf essential oil of F. koreana act against foodborne and other pathogenic bacteria. The mode of action revealed that this essential oil acted on the cytoplasmic membrane, resulting in loss of integrity and increased permeability. In addition, leaf essential oil of F. koreana was shown to be rich in linalool, which contributes to improved antioxidant activity. Conclusions: These results show that leaf essential oil of F. koreana has great potential as a natural food preservative, antibacterial and antioxidant agent.

Calcium fluxes in Hoplosternum littorale (tamoatá) exposed to different types of Amazonian waters

Fishes that live in the Amazonian environment may be exposed to several kinds of waters: "black waters", containing high dissolved organic carbon and acidic pH, "white waters", with ten fold higher Ca2+ concentrations than black waters and neutral pH, and "clear waters", with two fold higher Ca2+ concentrations than black waters and also neutral pH. Therefore, the aim of the present study was to analyze Ca2+ fluxes in the facultative air-breather Hoplosternum littorale (tamoatá) exposed to different Amazonian waters. Fishes were acclimated in well water (similar to clear water) and later placed in individual chambers for Ca2+ fluxes measurements. After 4 h, water from the chambers was replaced by a different type of water. Transfer of tamoatás to ion-poor black or acidic black water resulted in net Ca2+ loss only in the first 2 h of experiment. However, transfer from black or acidic black water to white water led to only net Ca2+ influxes. The results obtained allowed us to conclude that transfer of tamoatás to ion-poor waters (black and acidic black water) led to transient net Ca2+ loss, while the amount of Ca2+ in the ion-rich white water seems adequate to prevent Ca2+ loss after transfer. Therefore, transfer of tamoatás between these Amazonian waters does not seem to result in serious Ca2+ disturbance.(AU)

Os peixes que vivem na Amazônia são expostos a vários tipos de água: águas pretas, contendo grande quantidade de carbono orgânico dissolvido, águas brancas, com concentração de Ca2+ dez vezes maior que as águas pretas e pH neutro, e águas claras, com concentração de Ca2+ duas vezes maior que as águas pretas e pH também neutro. Dessa forma, o objetivo deste trabalho foi analisar o fluxo de Ca2+ no peixe de respiração aérea facultativa Hoplosternum littorale (tamoatá) exposto a diferentes tipos de águas amazônicas. Os peixes foram aclimatados em água de poço artesiano (semelhante à água clara) e depois colocados individualmente em câmaras para medir o fluxo de Ca2+. Após 4 h, a água das câmaras foi trocada por um tipo diferente de água. A transferência do tamoatá das águas pobres em íons água preta e preta ácida ou da água branca, rica em íons, para as águas preta e preta ácida, pobres em íons, resulta em uma perda de Ca2+ apenas nas duas primeiras horas de experimento. Entretanto, a transferência da água preta e preta ácida, para a água branca resulta em um influxo de Ca2+. Os resultados obtidos nos permitem concluir que a transferência do tamoatá para as águas preta e preta ácida, pobres em íons, leva a uma temporária perda de Ca2+, e a quantidade de Ca2+ na água branca, rica em íons, é adequada para prevenir sua perda após a transferência. Sendo assim, a transferência do tamoatá entre as águas estudadas não resulta em sérios distúrbios no Ca2+.(AU)

Combined stress of low environmental pressure and temperature on sodium and potassium homeostasis in rat blood.

Adult rats were subjected to the combined stress of low atmospheric pressure and temperature at a simulated altitude of 7620 metres and at 5°C for 5 hours. A significant increase in the influx of rubidium-86 and the efflux of sodium-22 was observed in erythrocytes of experimental rats in vitro. Blood 2,3-diphosphoglycerate was appreciably enhanced while blood sodium and reduced glutathione contents in the experimental animals remained unchanged.