In vitro bacteriostatic activity of Origanum vulgare, Cymbopogon citratus, and Lippia alba essential oils in cat food bacterial isolates

Abstract

The pet industry is currently expanding and specializing mainly in the field of domestic felines. Problems related to antimicrobial resistance are frequent, and the use of essential oils (EOs) in animal feed has become a novel treatment strategy. Thus, the objective of this study was to assess the bacteriostatic activity of Brazilian lemon balm (Lippia alba), lemon grass (Cymbopogon citratus), and oregano (Origanum vulgare) in bacterial isolates from 12 samples of cat food sold in bulk. The EOs from fresh leaves of crops were obtained from the Medicinal Garden of Paranaense University, Umuarama, Paraná. Cat food samples were processed for identification of gram-positive and gram-negative microorganisms. The determination of the bacteriostatic activity of the EOs was performed by determination of the minimum inhibitory concentration (MIC) at dilutions of 2.5, 1.25, and 0.62 mg/mL. The diffusion disc technique was used to evaluate the resistance profile to the main antimicrobials used in the feline clinic and to analyze the effect of the association of these antimicrobials with the EOs studied. A total of 23 isolates were obtained, of which 16 were gram-negative and seven were gram-positive. As for the oil composition for L. alba, C. citratus, and O. vulgare, 40, 24, and 44 compounds were identified, respectively, with the major ones being geranial, geranial/?-citral, and carvacrol, respectively. Regarding MIC, no differences were found for any EOs tested. The lowest MIC value was obtained for the C. citratus EO (0.83 mg/mL) for two bacteria (coagulase-negative Staphylococcus and Corynebacterium kutscheri). The means of the inhibition halos for the 10 antimicrobials tested in association or not with one of the EOs for Klebsiella aerogenes, Proteus vulgaris, and Serratia rubidaea showed that, for S. rubidaea, the inhibition halo diameter (12.4 mm) was greater (p < 0.05) when amoxicillin was associated with the O. vulgare EO than the association of the same antibiotic with the C. citratus EO (11.0 mm). For K. aerogenes and P. vulgaris, there was no difference in inhibition halo diameter when EOs were included. In conclusion, L. alba, C. citratus, and O. vulgare EOs are effective in inhibiting the growth of gram-positive and gram-negative bacteria and can be added to cat food to replace chemical antimicrobials.

In vitro antibacterial activity of crude ethanolic extract from the leaves of Origanum vulgare, against Staphylococcus aureus ATCC 29213, Pseudomonas aeruginosa ATCC 27853 and Escherichia coli ATCC 25922

“…The antibacterial and antioxidant properties of oregano have been attributed mainly to carvacrol and thymol, which are the main components of its essential oil that cause structural and functional alterations in the cell membrane [9][10][11] , Also in a study, the extracts of leaves of O. vulgare has also been tested for its bactericidal activity against different important pathogens for fish aquaculture [12][13][14] , with findings of activity against bacteria that cause periodontal diseases 15,16 , it is even used in the storage stability of meat and prevent its decomposition 17,18 .…”

CARACTERIZAÇÃO FITOQUÍMICA E ATIVIDADE ANTIBACTERIANA DO EXTRATO ETANÓLICO E DO ÓLEO ESSENCIAL DAS FOLHAS DE Cymbopogon citratus

“…A atividade direta do extrato etanólico e óleo essencial obteve uma CIM ≥ 1024 µg/mL, isso demonstra que não houve atividade antibacteriana intrínseca significativa, diante disso foi possível observar que o extrato etanólico e óleo essencial de C. citratus não possuem a capacidade de inibir o crescimento das bactérias testadas, sendo um fato relatado em estudos sobre Citrus limon L. e Sicana odorífera L. (CASTRO et al, 2010). Possamai et al (2019) analisaram, pelo método de disco-difusão, a CIM de três óleos essenciais de plantas aromáticas, inclusive a C. citratus, contra bactérias Gram positivas e negativas, isoladas de alimentos, e determinaram que, dentre os óleos, o de C. citratus teve a menor formação de halo de inibição, principalmente com a cepa do gênero Staphylococcus testada, corroborando com o presente trabalho, o qual não demonstrou atividade direta também para uma cepa deste gênero.…”

Potencial dos extratos vegetais como alternativa terapêutica isolada ou em associação sinérgica com fármacos dentro da Clínica de Felinos

“…Atualmente, estudos usando 19 fórmulas de óleos essenciais, todas do gênero Lippia spp., relataram resultados positivos contra as formas intracelulares de Leishmania chagasi e Trypanosoma cruzi Possamai et al (2019). atribui os resultados ao timol e S-carvone presentes naturalmente nos extratos e que possuem uma eficácia satisfatória contra formas amastigotas.…”