Effect of (+)-dehydrofukinone on GABAA receptors and stress response in fish model

Abstract

(+)-Dehydrofukinone (DHF) is a major component of the essential oil of Nectandra grandiflora (Lauraceae), and exerts a depressant effect on the central nervous system of fish. However, the neuronal mechanism underlying DHF action remains unknown. This study aimed to investigate the action of DHF on GABAA receptors using a silver catfish (Rhamdia quelen) model. Additionally, we investigated the effect of DHF exposure on stress-induced cortisol modulation. Chemical identification was performed using gas chromatography-mass spectrometry and purity was evaluated using gas chromatography with a flame ionization detector. To an aquarium, we applied between 2.5 and 50 mg/L DHF diluted in ethanol, in combination with 42.7 mg/L diazepam. DHF within the range of 10-20 mg/L acted collaboratively in combination with diazepam, but the sedative action of DHF was reversed by 3 mg/L flumazenil. Additionally, fish exposed for 24 h to 2.5-20 mg/L DHF showed no side effects and there was sustained sedation during the first 12 h of drug exposure with 10-20 mg/L DHF. DHF pretreatment did not increase plasma cortisol levels in fish subjected to a stress protocol. Moreover, the stress-induced cortisol peak was absent following pretreatment with 20 mg/L DHF. DHF proved to be a relatively safe sedative or anesthetic, which interacts with GABAergic and cortisol pathways in fish.

Application of herbal anaesthetics in aquaculture

“…), which acts on GABA A receptors to induce anaesthesia in fish (Garlet et al . ). The essential oil at the concentrations of 200–300 μL L −1 induced deep anaesthesia in tambaqui ( Colossoma macropomum ) within 1218–1321 s, with recover time of 269–324 s (Barbas et al .…”

“…It is a sesquiterpene found at high concentrations in N. grandiflora , acting on GABA A receptors to depress central nervous system (Garlet et al . ). The anaesthetic efficacy of dehydrofukinone has been studied in silver catfish, showing that it induced deep anaesthesia within 925 s with recovery time of longer than 1800 s, at 50 mg L −1 concentration.…”

“…No side effects were observed in the fish exposed to 2.5–20 mg L −1 dehydrofukinone for 24 h (Garlet et al . ).…”

Properties of two plant extractives as anaesthetics and antioxidants for juvenile tambaqui Colossoma macropomum

“…This plant contains dehydrofukinone (DHF), which represents the main component of its EO. DHF has been isolated and exerted a depressant effect on the central nervous system of silver catfish acting on GABA A receptors and also preventing the elevation of cortisol levels in blood plasma (Garlet et al, 2016).…”

<b>Supplementation with microencapsulated lemongrass essential oil improves protein deposition and carcass yield in silver catfish (<i>Rhamdia quelen</i>)

“…The identification of EO composition was determined using an Agilent 6890 gas chromatograph (GC) coupled to a mass spectrometry detector (MS) Agilent 5973 with a HP5-MS column (5% phenyl, 95% methylsiloxane, 30 m x 0.25 mm ID × 0.25 μM). The EO chemical constituents were identified by comparison of their retention indices, which were determined by a calibration curve of n-alkanes injected under the same chromatographic conditions as the samples and mass fragmentation patterns described in the literature (Garlet et al, 2016). The chemical constituents of the EO were quantified by GC coupled to flame ionization detector (FID) on an Agilent 7890A.…”