BACKGROUND: The use of plant compounds and their derivatives, such as extracts and essential oils, for combating infectious agents has attracted a great deal of scientific attention. One of the active antimicrobial compounds with plant origin is carvacrol.OBJECTIVES: The present study aimed to evaluate the antibacterial activity of carvacrol alone and in combination with the antibiotic cefixime against Escherichia coli O157:H7.METHODS: The antibacterial properties of carvacrol and cefexime were evaluated by determining the Minimum Inhibitory Concentration (MIC), Minimum Bactericidal Concentration (MBC), and disk diffusion method. The checkerboard assay was used to evaluate the interaction between the carvacrol and cefexime and to determine the fractional inhibitory concentration.RESULTS: The results showed that the MIC and MBC of carvacrol and cefexime against E.coli O157:H7 were 250, 250 μg/ml (MIC, MBC) and 128, 128 μg/ml (MIC, MBC), respectively. In the checkerboard test, carvacrol was found to have a synergistic interaction with antibiotic cefixime against E. coli O157:H7 (FIC index=0.5).CONCLUSIONS: Due to the significant antibacterial activity of carvacrol, the present study introduced this agent as a new antibacterial drug with a natural origin. In addition, since carvacrol significantly increased the antibacterial potential of cefixime (synergistic properties), it could be considered as an effective compound for increasing the antibacterial power of cefixime antibiotic.

Carvacrol is an essential oil derived from oregano that is used as a natural additive to improve the efficiency of livestock nutrition. Residues of natural additives such as carvacrol should be monitored in food of animal origin to ensure consumer safety. The aim of this study was to appraise the quick, easy, cheap, effective, rugged and safe (QuEChERS) approach coupled with liquid chromatography and mass spectrometry as a means of carvacrol analysis in chicken tissue.

Carvacrol is an essential oil extracted from oregano which can be used as a natural additive in poultry litter and could have a positive impact not only on production rates but also on the quality of poultry meat. The aim of this study was to evaluate the effect of the addition of carvacrol to litter on weight gain and the occurrence of residues in chicken tissues.

Carvacrol is an essential oil derived from oregano that is used as a natural additive to improve the efficiency of livestock nutrition. Residues of natural additives such as carvacrol should be monitored in food of animal origin to ensure consumer safety. The aim of this study was to appraise the quick, easy, cheap, effective, rugged and safe (QuEChERS) approach coupled with liquid chromatography and mass spectrometry as a means of carvacrol analysis in chicken tissue. A 5 ± 0.05 g portion of plasma, lung, muscle and liver was mixed for 15 min with 5 mL of 1-butanol and 20 mL of water, then centrifuged. A 0.5 mL volume from the top layer was transferred, then 60 mg of octadecylsilane sorbent, 30 mg of primary and secondary amine and 200 mg of MgSO₄ were added. The extract was mixed and centrifuged. The top layer was filtered and then transferred to an autosampler vial for analysis by high-performance liquid chromatography–tandem mass spectrometry. The limit of detection was calculated at 0.06 μg g⁻¹ and the limit of quantification was 0.2 μg g⁻¹, with relative standard deviation repeatability and reproducibility below <20%. The validation results showed that this method could be a good alternative to determination of carvacrol by gas chromatography and is suitable for carvacrol analysis in different matrices.

To compare the effect of intraperitoneal administered Carvacrol with bevacizumab in an oxygen-induced retinopathy (OIR) model in rats. Twenty-eight newborn rats were included in the study and the OIR model was created with the 50/10% oxygen style. The study consisted of 4 groups and each rat in the groups received an intraperitoneal injection of 0.01 mL once on the postnatal 14th day. While the OIR model was not created in Group I (control group), it was created for Groups II, III, and IV. Groups I and II were injected with 0.9% NaCl solution, Group III with bevacizumab, and Group IV with carvacrol. The rats were sacrificed on the postnatal 18th day.Histopathological and immunohistochemical studies showed that the number of retinal vascular endothelial cells (RVECs) and nuclear factor (NF)-κB levels decreased similarly in Group III and Group IV compared to Group II. RVECs values for Group I, Group II, Group III and Group IV were measured as 1.26±0.80, 27.10±3.63, 7.54±1.38, and 6.22±1.22, respectively and it differed significantly between groups (p<0.001). Likewise, NF-κB levels were recorded as 0.61 ± 0.30, 4.36±0.65, 2.68±0.44, and 2.85±0.58, respectively and it differed significantly between groups (p<0.001). On the other hand, RVECs and NF-κB levels were similar between Group III, and Group IV (p values were 0.58 and 0.91, respectively).The study demonstrated that carvacrol significantly reduced retinal pathological neovascularizations, RVECs, and NF-κB levels. Moreover, the observed effects were comparable to those of bevacizumab.

The inclusion of oregano essential oil, alone or associated with salinomycin, was evaluated as an alternative to zinc bacitracin on the performance of broiler chickens. This study used 600 male Cobb 500® day-old chicks, raised 42 days in boxes with rice hulls, provided with tubular feeders and nipple drinkers. The experimental design was completely randomized with six diets and 10 replications with 10 birds per experimental unit. The diets were based on corn and soybean meal: positive control - antibiotic (zinc bacitracin) + 0.05% anticoccidial (salinomycin), negative control - basal diet (BD) without additives, DB + 0.05% of salinomycin and 0.03% of oregano essential oil (Orego-Stim®),<br />DB + 0.03% of oregano essential oil, DB + 0.05% of salinomycin and 0.05% of oregano essential oil, DB + 0.05% of oregano essential oil. There were no treatment effects on broiler performance until 21 days of age. In the other periods, at 35 and 42 days, the oregano essential oil at 0.03% combined with salinomycin presented similar effects as the positive<br />control, leading to the conclusion that 0.03% of oregano essential oil associated with the salinomycin can replace zinc bacitracin + salinomycin in broiler chicken diets. | O presente trabalho teve como objetivo avaliar dietas com óleo essencial de orégano, associado ou não com salinomicina, como alternativa à bacitracina de zinco sobre o desempenho zootécnico de frangos de corte. Foram utilizados 600 pintos de um dia de idade, machos, da linhagem Cobb® 500, criados até 42 dias de idade em boxes com cama de casca de arroz providos de comedouros tubulares e bebedouros nipple. O delineamento foi inteiramente casualizado, com seis dietas e 10 repetições de 10 aves cada. As dietas experimentais à base de milho e farelo de soja foram: controle positivo – antibiótico (bacitracina de zinco) + 0,05% de anticoccidiano (salinomicina), controle negativo – dieta basal (DB) sem aditivos, DB + 0,05% de salinomicina e 0,03% de óleo essencial de orégano (Orego-Stim®), DB + 0,03% de óleo essencial de orégano, DB + 0,05% de salinomicina e 0,05% de óleo essencial de orégano, DB + 0,05% de óleo essencial de orégano. Não foi encontrado efeito da utilização do óleo de orégano até 21 dias no desempenho das aves. Nos demais períodos, aos 35 e 42 dias, o desempenho das aves tratadas com 0,03% de óleo essencial de orégano + salinomicina apresentou resultados semelhantes ao controle positivo, levando à conclusão de que a dose de 0,03% de óleo essencial de orégano + salinomicina pode substituir a bacitracina de zinco + salinomicina em dietas para frangos de corte.