Anesthetic activity of the essential oil of Ocimum americanum in Rhamdia quelen (Quoy & Gaimard, 1824) and its effects on stress parameters

Abstract

The aim of this study was to evaluate the anesthetic activity of the essential oil (EO) of Ocimum americanum L. in silver catfish (Rhamdia quelen). In the first experiment, the depressor effects and chemical composition of the leaf EO (LEO) and inflorescence EO (IEO) were compared. Juveniles (n = 10) were placed in aquaria containing different concentrations of EO (25 -500 mg L -1 ) to determine the point at which anesthesia was induced and the length of the recovery period. In the following experiment, the effects of 300 and 500 mg L -1 LEO exposure on stress parameters (plasma cortisol, glucose and sodium levels) after air exposure for 1 min were assayed. Fish (n = 10 per sampling time) were sampled immediately or transferred to anesthetic-free aquaria until sampling (15, 30, 60 or 240 min). LEO was composed mainly of β-linalool and 1,8-cineole in similar proportions, whereas IEO showed β-linalool as major compound. Anesthesia was obtained in silver catfish with 200-500 mg L -1 between 4-8 min for LEO and 6-16 min for IEO. Lower EO concentrations did not reach anesthetic stage up to 30 min. LEO used as anesthetic prevented the cortisol increase and sodium loss induced by aerial exposure. Glucose levels were raised in catfish exposed to LEO compared to basal group (not air exposed) in almost all observation times. EO of O. americanum obtained from leaves was considered suitable to anesthetic procedures due to its fast induction and handling-induced stress prevention.O objetivo deste trabalho foi avaliar a atividade anestésica do óleo essencial (EO) de Ocimum americanum L. em jundiás (Rhamdia quelen). No primeiro experimento, os efeitos depressores e a composição química dos óleos obtidos a partir das folhas (LEO) e das inflorescências (IEO) desta espécie vegetal foram comparados. Para isto, juvenis de jundiás (n = 10) foram transferidos para aquários contendo diferentes concentrações de EO (25 -500 mg L -1 ) a fim de determinar os tempos de indução aos estágios de anestesia e de recuperação. No experimento seguinte foram determinados os efeitos da exposição a 300 e 500 mg L -1 de LEO em parâmetros de estresse (cortisol, glicose e níveis de sódio plasmáticos) após os animais serem expostos durante 1 min ao ar. Os peixes (n = 10 por tempo de amostragem) foram coletados imediatamente ou transferidos para aquários livres de anestésico até amostragem (15, 30, 60 ou 240 min). LEO demonstrou ser composto majoritariamente por β-linalol e 1,8-cineol em proporções similares, enquanto que IEO apresentou β-linalol como constituinte majoritário. O estágio de anestesia foi verificado em jundiás com 200-500 mg L -1 entre 4-8 min para LEO e 6-16 min para IEO. Menores concentrações de ambos os EO não promoveram anesthesia até 30 min. O uso de LEO como anestésico preveniu o aumento de cortisol e a perda de sódio induzida pela exposição aérea. Já a glicemia encontrava-se aumentada em peixes expostos ao LEO em comparação ao grupo basal (não exposto ao ar) na maioria dos tempos de observação. Assim, EO de O. americanum obtido a par...

Relaxing effect of eugenol and essential oils in Pomacea canaliculata

“…The EO of O. americanum presented as major constituents eucalyptol, linalool, and eugenol, corroborating the results reported by SILVA et al (2015). The relaxing effect of this oil can be attributed to eugenol, which has been proven to have a relaxing effect in P. canaliculata, and linalool, which also has an anesthetic effect on silver catfish, Rhamdia quelen (HELDWEIN et al, 2014).…”

“…This effect was expected, since these compounds have an anesthetic effect in fish (GOMES et al, 2011, SILVA et al, 2015CUNHA, et al, 2017). Eugenol also presented anesthetic activity in crustaceans (PARODI et al, 2012).…”

Application of herbal anaesthetics in aquaculture

“…However, the essential oil led to a significant increase in plasma glucose after the stress (Silva et al . ).…”

“…Silva et al . () reported that essential oil of O. americanum is rich in cineole, camphor, linalool and eugenol, in which cineole and eugenol were the main components in the plant leaves essential oil, whereas linalool was the main component in the plant flowers. Anaesthesia induction of silver catfish lasted 501–240 s (the leaves essential oil) and 970–413 s (the flower essential oil) when exposed to 200–500 mg L −1 of the essential oil.…”

Phytochemical Analysis of Ocimum americanum Linn. with Special Reference to the Impact of In vitro Flowering on the Production of Aromatic Compounds

“…Some unique pharmacological properties and occurrence of bioactive principles of the essential oil has augmented the economic value of the species as a provider of natural compounds to pharmaceutical Industries. The essential oil has anaesthetic activity and the compounds present within it have effects on stress parameters 1 . The analgesic and anti inflammatory activity of the essential oil on laboratory animals has been demonstrated 2 .…”