Anesthesia of tambaqui Colossoma macropomum (Characiformes: Serrasalmidae) with the essential oils of Aniba rosaeodora and Aniba parviflora and their major compound, linalool

The aim of this study was to determine the anesthetic efficacy of the essential oils (EOs) of Aniba rosaeodora (EOAR) and Aniba parviflora (EOAP) and one of their main compounds, linalool, in two forms: synthetic and extracted from EOAR (linalool-AR) in tambaqui (Colossoma macropomum). In the first experiment, the anesthetic induction and recovery of juveniles exposed to 25- 200 µL L-1 of EOAR or 50- 300 µL L-1 of EOAP or synthetic linalool or linalool-AR was evaluated. The second experiment observed the behavioral effects of long-term exposure (12h) of these EOs and linalools (5 and 10 µL L-1). Fish exposed to 50-200 µL L-1 of EOAR and 100-300 µL L-1 of EOAP and both linalools reached deep anesthesia between 1-10 min. Induction time for all anesthesia stages decreased with the increasing concentration of the anesthetics. Linalool-AR showed lengthier time for anesthesia induction in some stages and for recovery at 100 and 200 µL L-1 in comparison to synthetic linalool. Normal equilibrium and swimming behavior was observed in fish exposed to the EOs and linalools throughout the 12 h of exposure. In conclusion, both EOs and linalools can be used as anesthetics and sedatives in tambaqui.(AU)

O objetivo deste trabalho foi determinar a eficácia anestésica dos óleos essenciais (OEs) de Aniba rosaeodora (OEAR) Aniba parviflora (OEAP) e um de seus compostos majoritários, linalol, em duas formas: sintética e extraída a partir de OEAR (linalol-AR) em tambaqui (Colossoma macropomum). No primeiro experimento avaliou-se a indução anestésica e a recuperação de juvenis expostos a 25- 200 µL L-1 de EOAR ou 50- 300 µL L-1 de EOAP ou linalol sintético ou linalol-AR. No segundo experimento observaram-se os efeitos comportamentais de uma longa exposição (12h) a estes OEs e linalois (5 e 10 µL L-1). Os peixes expostos a 50-200 µL L-1 de EOAR e 100-300 µL L-1 de OEAP e ambos os linalois alcançaram anestesia profunda entre 1-10 min. Tempo de indução a todos os estágios de anestesia diminuiu com o aumento na concentração dos anestésicos. Linalol-AR levou um maior tempo para induzir anestesia e para recuperação com 100 e 200 µL L-1 em comparação ao composto sintético. Peixes expostos aos OES e linalois por 12 h apresentaram equilíbrio e comportamento natatório normais. Em conclusão, tanto os OEs como o linalol sintético ou natural de AR podem ser usados como anestésicos e sedativos em tambaqui.(AU)

S-(+)- and R-(-)-linalool: a comparison of the in vitro anti-Aeromonas hydrophila activity and anesthetic properties in fish.

Linalool is the main compound of many essential oils and occurs in two isomeric forms: S-(+)- and R-(-)-linalool. This study aimed to determine if linalool isomers have different antimicrobial and anesthetic properties in fish. For this purpose, these compounds were previously isolated from Lippia alba (Mill.)N. E. Brown and Ocimum americanum L. essential oils. Antimicrobial effects were evaluated through the microdilution test against Aeromonas hydrophila, an important fish disease etiologic agent. Induction time until sedation, anesthesia and recovery time were determined in silver catfish (Rhamdia quelen) through bath exposure (60, 180, 300 or 500 µL L-1). The results showed different biological properties for the isomers being S-(+)-linalool the only active against A. hydrophila at 3.2 mg mL-1. The sedation was induced without differences between the compounds, however R-(-)-linalool promoted faster anesthesia. There were no differences regarding the recovery time of the animals exposed to the linalool isomers. Although both S-(+)- and R-(-)-linalool can be used for sedative purposes, their use in A. hydrophila infection is inadvisable due to the high effective concentration. Considering anesthesia as the main objective, the R-(-)-linalool demonstrated clear advantages at lower concentration.

S-(+)- and R-(-)-linalool: a comparison of the in vitro anti-Aeromonas hydrophila activity and anesthetic properties in fish

ABSTRACT Linalool is the main compound of many essential oils and occurs in two isomeric forms: S-(+)- and R-(-)-linalool. This study aimed to determine if linalool isomers have different antimicrobial and anesthetic properties in fish. For this purpose, these compounds were previously isolated from Lippia alba (Mill.)N. E. Brown and Ocimum americanum L. essential oils. Antimicrobial effects were evaluated through the microdilution test against Aeromonas hydrophila, an important fish disease etiologic agent. Induction time until sedation, anesthesia and recovery time were determined in silver catfish (Rhamdia quelen) through bath exposure (60, 180, 300 or 500 μL L-1). The results showed different biological properties for the isomers being S-(+)-linalool the only active against A. hydrophila at 3.2 mg mL-1. The sedation was induced without differences between the compounds, however R-(-)-linalool promoted faster anesthesia. There were no differences regarding the recovery time of the animals exposed to the linalool isomers. Although both S-(+)- and R-(-)-linalool can be used for sedative purposes, their use in A. hydrophila infection is inadvisable due to the high effective concentration. Considering anesthesia as the main objective, the R-(-)-linalool demonstrated clear advantages at lower concentration.

Anesthetic activity and bio-guided fractionation of the essential oil of Aloysia gratissima (Gillies & Hook.) Tronc. in silver catfish Rhamdia quelen.

This work aimed to determine the efficacy of the essential oil of A. gratissima as anesthetic for silver catfish, and to perform the bio-guided fractionation of essential oil aiming to isolate compounds responsible for the noted effects. Fish were submitted to anesthesia bath with essential oil, its fractions and isolated compounds to determine time of anesthetic induction and recovery. Eugenol (50 mg L(-1)) was used as positive control. Essential oil of A. gratissima was effective as an anesthetic at concentrations of 300 to 900 mg L(-1). Fish presented involuntary muscle contractions during induction and recovery. The bio-guided fractionation of essential oil furnished E-(-)-pinocamphone, (-)-caryophyllene oxide, (-)-guaiol and (+)-spathulenol. E-(-)-pinocamphone caused the same side effects observed for essential oil. (-)-Caryophyllene oxide, (-)-guaiol and (+)-spathulenol showed only sedative effects at proportional concentrations to those of the constituents in essential oil. (+)-Spathulenol (51.2 mg L(-1)) promoted deep anesthesia without side effects. A higher concentration of (+)-spathulenol, and lower or absent amounts ofE-(-)-pinocamphone could contribute to increase the activity and safety of the essential oil of A. gratissima. (+)-Spathulenol showed potent sedative and anesthetic activities in silver catfish, and could be considered as a viable compound for the development of a new anesthetic.

Composição química, atividade antibacteriana in vitro e toxicidade em Artemia salina do óleo essencial das inflorescências de Ocimum gratissimum L., Lamiaceae / Chemical composition, antibacterial activity in vitro and brine-shrimp toxicity of the essential oil from inflorescences of Ocimum gratissimum L., Lamiaceae.

O óleo essencial das inflorescências de Ocimum gratissimum L., Lamiaceae foi obtido por hidrodestilação e analisado por CG/EM. Os constituintes majoritários identificados foram eugenol (81,94 por cento) e γ-muuroleno (12,58 por cento). O óleo essencial das inflorescências demonstrou atividade antibacteriana frente a todas as cepas bacterianas testadas pelo método de microdiluição em caldo. Merece destaque a atividade verificada frente às cepas resistentes de Enterococcus faecalis, Staphylococcus aureus e Escherichia coli. Os valores obtidos de concentração inibitória mínima (CIM) e a concentração bactericida mínima (CBM) variaram, respectivamente, entre 0,5-2 mg/mL e 1-4 mg/mL. Valores de CL50 de 233,8 (200,7-272,0) µg/mL para o óleo essencial e 186,1 (144,1-228,5) µg/mL para o eugenol, utilizado como controle positivo, foram observados frente à Artemia salina L.

The essential oil obtained by hydrodistillation of the inflorescences of Ocimum gratissimum L. was analyzed by GC/MS. The main constituents were eugenol (81.94 percent) and γ-muurolene (12.58 percent). Antibacterial activity was shown against all assayed strains by the broth microdilution method. It's worth noting the activity against resistant strains of Enterococcus faecalis, Staphylococcus aureus and Escherichia coli. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values ranged between 0.5-2 mg/mL and 1-4 mg/mL, respectively. Preliminary toxicity assayed by the brine-shrimp (Artemia salina L.) test showed LC50 values of 233.8 (200.7 - 272.0) µg/mL and 186.1 (144.1 - 228.5) µg/mL, respectively for the essential oil and eugenol (positive control).