Nanoencapsulated Melaleuca alternifolia essential oil exerts anesthetic effects in the brachyuran crab using Neohelice granulate.

The aim of this study was to evaluate the efficacy and safety of several anesthetics in the brachyuran crab Neohelice granulata, an emergent experimental model. The essential oils (EOs) of Lippia alba, Aloysia tryphilla, and Melaleuca alternifolia (tea tree oil; TTO), the isolated compounds eugenol, menthol, terpinen-4-ol, and the nanoencapsulated form of TTO, were administered in one or more of the following ways: added to the water (immersion), through an arthrodial membrane (injected), or by oral gavage. Unexpectedly, most EOs did not produce an anesthetic effect after immersion. Only TTO and eugenol induced anesthesia by immersion, with very long induction and recovery times compared to anesthesia of other crustaceans. However, a good anesthetic effect was observed with the injection of terpinen-4-ol and nanoencapsulated TTO in N. granulata; both demonstrated ideal induction and recovery times. These substances appear to be promising anesthetic alternatives for crustaceans.

Aloysia triphylla in the zebrafish food: effects on physiology, behavior, and growth performance.

Dietary supplements are commonly used by animals and humans and play key roles in diverse systems, such as the immune and reproductive systems, and in metabolism. Essential oils (EOs), which are natural substances, have potential for use in food supplementation; however, their effects on organisms remain to be elucidated. Here, we examine the effects of dietary Aloysia triphylla EO supplementation on zebrafish behavior, metabolism, stress response, and growth performance. We show that fish fed diets containing A. triphylla EO presented an anxiolytic response, with reduced exploratory activity and oxygen consumption; no changes were observed in neuroendocrine stress axis functioning and growth was not impaired. Taken together, these results suggest that the A. triphylla EO supplementation is a strong candidate for use in feed, since it ensures fish welfare (anxiolytic behavior) with decreased oxygen consumption. This makes it suitable for use in high-density production systems without causing damage to the neuroendocrine stress axis and without growth performance being impaired.

The Essential Oil of Hyptis mutabilis in Ichthyophthirius multifiliis Infection and its Effect on Hematological, Biochemical, and Immunological Parameters in Silver Catfish, Rhamdia quelen.

This study evaluated the activity of leaf essential oil (EO) from Hyptis mutabilis as well as its major constituent, (-)-globulol, in infections by the parasite Ichthyophthirius multifiliis (ich). Effects on hematological, biochemical, and immunological parameters of silver catfish, Rhamdia quelen, exposed to the same samples also were evaluated. In the first experiment, naturally infected fish were treated with EO (0, 10, and 20 mg · L-1) and ethanol, using several methods of exposure. Fish mortality and the number of trophonts per fish were assessed after 48 and 96 hr. Hour-long daily baths resulted in optimal survival, so this methodology was used for the second experiment, in which infected animals were exposed to (-)-globulol at 2.5 and 5 mg · L-1. The most effective concentrations in Experiments 1 and 2 were chosen for Experiment 3, in which healthy animals were subjected to hour-long daily baths with EO (20 mg · L-1) or (-)-globulol (2.5 mg · L-1). Additionally, an in vitro experiment was performed with EO and globulol at the same concentrations of the in vivo test. EO and (-)-globulol increased the survival of fish infected with ich and altered certain hematological and biochemical parameters. After 4 days, levels of hematocrit, erythrocytes, and leukocytes increased significantly in healthy animals exposed to EO. Exposure to (-)-globulol increased leukocyte number alone. No significant differences in nonspecific immunological parameters were detected when treated groups were compared to controls, but the leukocytosis observed in EO- and globulol-treated healthy animals indicates that EO and (-)-globulol increased innate immunity in these fish. An in vitro antiparasitic effect was observed in both samples.

Anesthesia of Epinephelus marginatus with essential oil of Aloysia polystachya: an approach on blood parameters.

This study investigated the anesthetic potential of the essential oil (EO) of Aloysia polystachya in juveniles of dusky grouper (Epinephelus marginatus). Fish were exposed to different concentrations of EO of A. polystachya to evaluate time of induction and recovery from anesthesia. In the second experiment, fish were divided into four groups: control, ethanol and 50 or 300 µL L-1 EO of A. polystachya, and each group was submitted to induction for 3.5 min and recovery for 5 or 10 min. The blood gases and glucose levels showed alterations as a function of the recovery times, but Na+ and K+ levels did not show any alteration. In conclusion, the EO from leaves of A. polystachya is an effective anesthetic for dusky grouper, because anesthesia was reached within the recommended time at EO concentrations of 300 and 400 µL L-1. However, most evaluated blood parameters showed compensatory responses due to EO exposure.

Anesthesia of Epinephelus marginatus with essential oil of Aloysia polystachya: an approach on blood parameters

ABSTRACT This study investigated the anesthetic potential of the essential oil (EO) of Aloysia polystachya in juveniles of dusky grouper (Epinephelus marginatus). Fish were exposed to different concentrations of EO of A. polystachya to evaluate time of induction and recovery from anesthesia. In the second experiment, fish were divided into four groups: control, ethanol and 50 or 300 µL L−1 EO of A. polystachya, and each group was submitted to induction for 3.5 min and recovery for 5 or 10 min. The blood gases and glucose levels showed alterations as a function of the recovery times, but Na+ and K+ levels did not show any alteration. In conclusion, the EO from leaves of A. polystachya is an effective anesthetic for dusky grouper, because anesthesia was reached within the recommended time at EO concentrations of 300 and 400 µL L−1. However, most evaluated blood parameters showed compensatory responses due to EO exposure.

Aloysia triphylla essential oil as additive in silver catfish diet: Blood response and resistance against Aeromonas hydrophila infection.

The essential oil of Aloysia triphylla (EOAT) is a promising product with potential use in aquaculture systems. This study evaluated hematological/biochemical responses and survival of silver catfish (Rhamdia quelen) fed a diet containing EOAT and infected by Aeromonas hydrophila. After 21 days of feeding trial, fish were infected with A. hydrophila following a 10-day period of observation. Blood collection was performed before and after the bacterial challenge. Dietary EOAT by itself seems to affect some blood parameters, decreasing total leukocyte, lymphocyte, and neutrophil counts and increasing total protein values. However, 2.0 mL EOAT/kg diet showed a possible potential protective effect after A. hydrophila infection, maintaining the evaluated parameters similar to basal values (from healthy fish before the feeding trial) and promoting survival of silver catfish.

Anesthesia and anesthetic action mechanism of essential oils of Aloysia triphylla and Cymbopogon flexuosus in silver catfish (Rhamdia quelen).

OBJECTIVES: To document the time for anesthesia induction and recovery using different concentrations of essential oils (EOs) of Cymbopogon flexuosus and Aloysia triphylla in silver catfish (Rhamdia quelen), and to determine whether the mechanism of action of either EO involves the benzodiazepine (BDZ) site of the GABAA receptor. STUDY DESIGN: Experimental study. ANIMALS: A total of 144 silver catfish, length 7.5 ± 1.1 cm, weighing 3.95 ± 0.85 g. METHODS: Essential oils were evaluated at concentrations of 25, 150 and 300 µL L-1, and also ethanol alone (seven groups, n = 6 per group). Induction of sedation or anesthesia and recovery were assessed. In a further six groups (n = 6 per group), fish were exposed to both EOs (25, 150 or 300 µL L-1) with diazepam 150 µm, and also diazepam (10 µm) alone. Flumazenil (5 or 10 µm) was added to the recovery water of fish exposed to diazepam (150 µm) or both EOs (150 and 300 µL L-1) (total of 10 groups = 60 fish). RESULTS: Both EOs induced anesthesia at concentrations of 150 and 300 µL L-1, and sedation at 25 µL L-1. There was no significant difference between EOs for reaching deep anesthesia; there was a significantly longer recovery time for the EO of C. flexuosus. The addition of diazepam (150 µm) resulted in faster induction of anesthesia with both EOs, with no significant change in recovery times. Flumazenil (10 µm) reversed the diazepam-induced anesthesia, but not the anesthesia induced by EOs. CONCLUSIONS AND CLINICAL RELEVANCE: The EO of C. flexuosus induced effective sedation (25 µL L-1) and anesthesia (150 and 300 µL L-1) without short-term mortality. The modulation of the BDZ site of the GABAA receptor in the anesthetic action mechanism of both EOs was not demonstrated.

Evaluation of Ocimum americanum essential oil as an additive in red drum (Sciaenops ocellatus) diets.

This study evaluated productive parameters, whole-body composition, non-specific immune responses and pH and microbiota of digestive tract contents of red drum (Sciaenops ocellatus) fed diets supplemented with Ocimum americanum essential oil (OAEO) (0 - control, 0.25, 0.5, 1.0 and 2.0 g/kg diet). After 7 weeks no significant differences in productive parameters and whole-body composition were observed. Plasma and intestinal lysozyme measurements and pH of the stomach and intestine (6 h after feeding) did not show significant differences among groups. Intestinal microbial community in fish fed the basal and OAEO diets (all concentrations) were identical. However, red drum fed the diet with OAEO at 1.0 g/kg had significantly increased intraperitoneal fat deposition and stomach pH (2 h after feeding) and decreased superoxide ion production (NBT-test) compared to the control group. Hemolytic activity of the complement system increased in fish fed diets containing OAEO. Red blood cells from fish fed the lowest OAEO concentration (0.25 g/kg) showed significant lower fragility in erythrocyte osmotic fragility assay, but fish fed 0.5 and 1.0 g/kg showed significant higher erythrocyte fragility. Lysozyme measurement in the supernatant of stomach content was significantly higher in fish fed the diet supplemented at 0.5 g/kg. Based on these various results, OAEO at different supplementation levels did not influence growth performance and intestinal microbial community; however, the EO added to the diet showed effects on immunological responses of red drum.

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.

Lippia alba essential oil promotes survival of silver catfish (Rhamdia quelen) infected with Aeromonas sp.

In vitro and in vivo activity of the Lippia alba essential oil (EO) against Aeromonas sp. was evaluated. In the in vitro assay the minimum inhibitory concentration (MIC) and a minimum bactericidal concentration (MBC) of EO for Aeromonas cells were determined using the microdilution method. Twenty five strains of Aeromonas sp. isolated from infected fish obtained from local fish farms were used. MIC and MBC values were 2862 and 5998 µg mL-1 for L. alba EO and 0.5 and 1.2 µg mL-1 for gentamicin, respectively. In the in vivo assay silver catfish juveniles (Rhamdia quelen) (7.50 ± 1.85 g and 10.0 ± 1.0 cm) with typical injuries associated to Aeromonas infection were divided into four treatments (in triplicate n=10): untreated fish (negative control), 10 mg L-1 of gentamicin, and 20 or 50 µL L-1 of EO. Fish were maintained in aerated 20 L plastic boxes. After 10 days survival of silver catfish infected with Aermonas sp. and treated with essential oil (50 µL L-1) was greater than 90%.

S-(+)-Linalool from Lippia alba: sedative and anesthetic for silver catfish (Rhamdia quelen).

OBJECTIVE: The present study describes the isolation of linalool from the essential oil of Lippia alba (Mill.) N. E. Brown, and its anesthetic effect in silver catfish (Rhamdia quelen) in comparison with essential oil. The potentiation of depressant effects of linalool with a benzodiazepine (BDZ) and the involvement of GABAergic system in its antagonism by flumazenil were also evaluated. STUDY DESIGN: Prospective experimental study. ANIMALS: Juvenile silver catfish unknown sex weighing mean 9.24 ± 2.83 g (n = 6 for each experimental group per experiment). METHODS: Column chromatography was used for the isolation of S-(+)-linalool. Fish (n = 6 for each concentration) were transferred to aquaria with linalool (30, 60, and 180 µL L(-1)) or EO of L. alba (50, 100, and 300 µL L(-1)) to determine the induction time for anesthesia. After induction, the animals were transferred to anesthetic-free aquaria to assess their recovery time. To observe the potentiation, fish were exposed to linalool (30, 60, and 180 µL L(-1)) in the presence or absence of BDZ (diazepam 150 µm). In another experiment, fish exposed to linalool (30 and 180 µL L(-1) or BDZ were transferred to an anesthetic-free aquaria containing flumazenil (5 µm) or water to assess recovery time. RESULTS: Linalool had a similar sedation profile to the essential oil at a proportional concentration in silver catfish. However, the anesthesia profile was different. Potentiation of linalool effect occurred only when tested at low concentration. Fish exposed to BDZ showed faster anesthesia recovery in water with flumazenil, but the same did not occur with linalool. CONCLUSIONS AND CLINICAL RELEVANCE: The use of linalool as a sedative and anesthetic for silver catfish was effective at 30 and 180 µL L(-1), respectively. The mechanism of action seems not to involve the benzodiazepine site of the GABAergic system.

Anesthetic activity of the essential oil of Aloysia triphylla and effectiveness in reducing stress during transport of albino and gray strains of silver catfish, Rhamdia quelen.

This study investigated the efficacy of the essential oil (EO) of Aloysia triphylla as an anesthetic for albino and gray strains of silver catfish, Rhamdia quelen. Juveniles were exposed to concentrations between 20 and 800 µL L(-1) EO of A. triphylla to evaluate time of induction and recovery from anesthesia. In another experiment, both strains were divided into four groups such as 0 (control), 30, 40, or 50 µL L(-1) EO and transported for 5 h. The longest time for anesthetic induction and recovery was observed in the albinos. Both strains reached anesthesia in the 100-800 µL L(-1) (11.1-1.24 min) range, without mortality, being 200 µL L(-1) the best response considering time to anesthesia (5.35 min). Albinos transported with all EO concentrations showed higher values of carbon dioxide in the water of transport, but lower levels were observed in grays transported with 40 and 50 µL L(-1) EO when compared to control fish. The same concentrations did not prevent significant whole-body cortisol rise at the end of transport in the albino strain. Juveniles of both strains transported with EO presented lower ion loss to the water compared to control fish. The EO of A. triphylla is an effective anesthetic for albino and gray silver catfish. This EO increases whole-body cortisol levels in the albino strain, but as it reduces net ion loss as in the gray strain, it can be also recommended for transport.

Atividade antimicrobiana do oleorresina de copaíba (Copaifera reticulata) frente a Staphylococcus coagulase positiva isolados de casos de otite em cães / Antimicrobial activity of copaiba oil (Copaifera reticulata) against coagulase positive Staphylococcus of canine otitis

The aim of this study was to investigate the antimicrobial activity of the oleoresin Copaifera reticulata Ducke against Staphylococcus coagulase positive (SCP) isolated from otitis externa in dogs. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of the oleoresin were determined by broth microdilution method. In addition, we verified the antimicrobial susceptibility profile of the isolates of SCP by agar diffusion method. Eight classes of antimicrobial were used to calculate the multidrug resistance. The chemical composition of the oleoresin was performed by gas chromatography coupled to the mass spectrometry (GC/MS), and β-caryophyllene, β-bisabolene, and (E)-α-bergamotene were the main compounds found. The copaiba oleoresin showed a MIC90 of 0.164mg/mL and a CBM90 of 1.3mg/mL. The multidrug resistance was found in 27% of the strains tested. The results suggest that copaiba oleoresin has bacteriostatic and bactericidal activity even in multidrug-resistant coagulase-positive strains.

O objetivo do presente trabalho foi investigar o potencial antimicrobiano do oleorresina de Copaifera reticulata Ducke em isolados de Staphylococcus coagulase positiva (SCP) provenientes de casos de otite externa em cães. O método de microdiluição em caldo foi utilizado para determinação da concentração inibitória mínima (CIM) e concentração bactericida mínima (CBM) de oleorresina de copaíba. Em adição, foi determinado o perfil de suscetibilidade aos antimicrobianos dos isolados de SCP pelo método de difusão em ágar. Oito classes de antimicrobianos foram usadas para o cálculo de multirresistência antimicrobiana. A determinação da composição química do oleorresina de copaíba foi realizada por cromatografia em fase gasosa acoplada à espectrometria de massas (GC/MS), sendo que β-cariofileno, β-bisaboleno e (E)-α-bergamoteno foram os compostos majoritários. O oleorresina de copaíba demonstrou CIM90 de 0,164mg/mL e CBM90 de 1,31mg/mL. A multirresistência foi verificada em 27% das cepas testadas. Os resultados sugerem que o oleorresina de copaíba exerceu atividade bacteriostática e bactericida mesmo em cepas multirresistentes de Staphylococcus coagulase-positiva.

Lipid stability during the frozen storage of fillets from silver catfish exposed in vivo to the essential oil of Lippia alba (Mill.) NE Brown.

BACKGROUND: Lippia alba is effective in sedating and reducing stress to fish during transportation. Because some in vitro studies have demonstrated the antioxidant activity of L. alba, we hypothesized that its use in vivo could result in antioxidant effects post mortem. Therefore, in this study we evaluated whether the essential oil of L. alba (EO) used as sedative for fish transport would increase the lipid stability of fillets from silver catfish during frozen storage. RESULTS: The exposure to the EO in vivo did not affect conjugated diene values. However, EO (30 and 40 µL L(-1)) delayed the peak formation of peroxides (from the third to the sixth month of storage) and thiobarbituric reactive substances (from the ninth to the twelfth month of storage) when compared to control fillets. After exposure to 40 µL L(-1) EO the free fatty acid content was higher than for control at the start of fillet storage, with no differences among groups thereafter. CONCLUSION: The essential oil of L. alba used as sedative in the water to transport silver catfish can delay lipid oxidation of fillets during frozen storage. Thus L. alba may be a promising source of natural active compounds for use in aquaculture and the food industry.

A triterpene ozonide from Senecio selloi.

From the dried and fresh aerial parts of Senecio selloi Spreng, De Candolle (Asteraceae), the new triterpene ozonide 1 was isolated. Its structure was elucidated by NMR experiments, including inverse techniques HMQC and HMBC and by synthesis from the precursor 2 In contrast to natural peroxides, no antiplasmodial activity was detected for the ozonide 1.

Screening of Brazilian plants for the presence of peroxides

Chloroform or dichloromethane extracts of 357 southern Brazilian plant species were tested for the presence of peroxides by thin-layer chromatography, using the spray reagent from Huber & Fröhlke. >From the species tested, 71 (20 por cento) showed positive results and most of them (56 por cento) are Asteraceae species. The species tested were mainly from Asteraceae, but 55 more families were screened, in a total of 77 genera surveyed...