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The objective was to verify the antibacterial activity of lemongrass and clove oils against Escherichia coli isolated from poultry feces, Staphylococcus aureus isolated from swine and poultry feces and Salmonella sp. isolated from swine and bovine feces. The antimicrobial activity was evaluated by the disc diffusion test using different concentrations of the oils: 160, 80, 40, 20 and 10 ?l ml -1. The multi-resistance of strains relative to that of conventional antimicrobials was also evaluated by the disk diffusion technique, using Multiple Antibiotic Resistance (MAR) index. The oils were characterized based on the results of chromatographic analyses, of which, analysis of lemongrass has been previously published (AZEVEDO et al., 2016). Lemongrass and clove essential oils presented citral and eugenol as the major compound, respectively. The concentrations of the essential oils had a significant effect on the extent of the growth inhibition halo and the coefficient of determination (r²) was higher than 0.80. Clove essential oil generated the largest zone of inhibition when tested against Escherichia coli and S. aureus from poultry feces and Salmonella sp. from the feces of swine, while lemongrass essential oil presented better results against S. aureus isolated from swine feces and Salmonella sp. from bovine feces. S. aureus and Salmonella sp. were multi-resistant to the antimicrobials tested. It is concluded that the essential oils tested have antimicrobial activity against bacteria isolated from bovine, swine, and poultry feces and that this activity is proportional to the concentration of oils and the microorganisms studied.

This study aimed at investigating the effect of fermented dairy beverage with clove essential oil (CEO) on the levels of reactive oxygen species (ROS) through endogenous enzymes superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx). For this, bioinformatic analysis was performed using the Genecards and String platforms. Headspace was used to analyze and confirm the compounds at low concentrations. Antioxidant activity was analyzed using the DPPH free radical sequestration method. For analysis of antioxidant activity, twenty-four male Swiss mice were divided into three groups and submitted histopathological analysis, analysis of CAT, SOD,GPx transcripts, and CAT and SOD enzyme activity in visceral adipose tissue were evaluated.The leader genes found were PIK3CD, PIK3CB, AKT1, and PIK3CA, as they had the highest WNL values. The beverage containing CEO showed higher antioxidant activity, with free radical scavenging capacity above 80%. In the in vivo analyses, it was possible to verify a reduction in the average adipocyte area size (μm2) between the groups that received fermented dairy beverage. Although functional studies have shown that the antioxidant enzymes, CAT and SOD, showed similar concentrations in visceral adipose tissue of the three groups, the expression levels of GPx1, CAT, and SOD were higher in group 2. Surprisingly, the group 3, that received the fermented dairy beverage with CEO had the lowest SOD concentration (p <0.05). Therefore, the antioxidant mechanism of the CEO can be mediated by the activation of the cell survival pathway PI3K/Akt and modulation of SOD1 and CAT enzymes by means of ROS reduction.

Previous studies have shown that the clove essential oil concentration of 200 mg/kg did not present toxicity and histopathological changes in the liver. Based on the evidence presented in this  study, we decided to evaluate in vivo the ability of a previously developed fermented dairy beverage, tested only in vitro, in which the standard chemical preservative, potassium sorbate, was replaced by clove essential oil (2 μl/ml), to be a functional food. To this end, twenty-four male Swiss mice were divided into three groups and submitted insulin sensitivity (IST) and glucose tolerance (GTT) testing, evaluation of physiological and biochemical parameters, histopathological analysis and quantification of the expression of anti-inflammatory and pro-inflammatory cytokines in the liver, after administering daily of the fermented dairy beverage with or without clove essential oil by gavage during 30 days. The group that received the fermented dairy beverage with clove essential oil showed a lower glycemic level in GTT, a higher sensitivity to insulin and a higher glucose decay constant rate (Kitt), with relation to the other groups. In the evaluation of physiological parameters there were no signs of toxicity in the mice during the experimental period. The biochemical parameters, histopathological analysis and expression of anti-inflammatory (IL-10) and pro-inflammatory (IL1β, IL6 e TNFα) cytokines in the liver of the mice, was not significantly affected by the treatment. These results corroborated by bioinformatics analysis demonstrate that the fermented dairy beverage with clove essential oil it can function as a substitute for conventional chemical preservatives and reduce glycemic levels.