RESUMO
Empirical knowledge of natural plant extracts is increasingly proving to be a promising field. The effect of Calendula officinalis L. (CO) and Capsicum annum (CA) glycolic extracts (GlExt) have potential that should be further developed in microbial tests. The effect of CO-GlExt and CA-GlExt was evaluated on eight multidrug-resistant clinical strains of Klebsiella pneumoniae and Pseudomonas aeruginosa, as well as collection strains for each bacterial. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of the extract were determined in comparison with 0.12% chlorhexidine. The tests were performed on single species biofilms, at 5 min and 24 h, using the MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide) assay. The MIC and MBC of the extract ranged from 1.56 to 50 mg mL-1 for all strains evaluated. Analysis of the MTT assay revealed a strong antimicrobial potential of CA-GlExt, comparable to chlorhexidine. The findings suggest that CA-GlExt is effective against multidrug-resistant strains of K. pneumoniae and P. aeruginosa in planktonic state and biofilms.
Assuntos
Calendula , Capsicum , Antibacterianos/farmacologia , Pseudomonas aeruginosa , Klebsiella pneumoniae , Glicóis/farmacologia , Clorexidina/farmacologia , Plâncton , Biofilmes , Mentol/farmacologia , Cânfora/farmacologia , Extratos Vegetais/farmacologia , Testes de Sensibilidade MicrobianaRESUMO
Extratos de plantas têm demonstrado diversos efeitos positivos para a saúde, incluindo ação antimicrobiana, no entanto, o uso clínico da fitoterapia ainda é discreto, de modo que mais estudos sobre os efeitos benéficos do sinergismo farmacológico de extratos poderiam contribuir para sua aplicação terapêutica. O objetivo deste estudo foi avaliar os efeitos dos extratos glicólicos de gengibre (EG) e quilaia (EQ) isolados e em associação sobre 7 cepas clínicas de Pseudomonas aeruginosa e uma cepa padrão em forma planctônica e biofilmes monotípicos. Para a análise antimicrobiana sobre cultura planctônica foram feitos testes para determinação de Concentração Inibitória Mínima (CIM) e Concentração Microbicida Mínima (CMM) (CLSI, M07-A9) dos extratos isolados, além do Índice de Concentração Inibitória Fracionada (ICIF) e do Índice de Concentração Microbicida Fracionada (ICMF) para os extratos combinados. A análise estatística foi feita com método ANOVA e teste de Tukey para dados com distribuição normal e Kruskall-Wallis com Teste de Comparação Múltipla de Dunn para dados sem distribuição normal (significância de 5%). Para cepa padrão foram determinadas CIM igual a 3,12 mg/mL e CMM igual a 6,25 mg/mL para ambos os extratos. Para cepas clínicas as CIM do EG foram 3,12 ou 6,25 mg/mL e de EQ 1,56 ou 3,12 mg/mL, enquanto os valores de CMM foram de 6,25 mg/mL para EG e de 1,56, 3,12 ou 6,25 mg/mL para EQ. Os resultados de ICIF indicaram 15 associações sinérgicas e 4 associações aditivas dos extratos contra a cepa padrão e, dentre cepas clínicas, foram obtidos 15 resultados aditivos. A partir dos resultados de ICMF foram identificadas 6 associações sinérgicas e 1 associação aditiva contra a cepa padrão, além de 8 associações com efeito aditivo contra cepas clínicas. A partir dos resultados de testes em culturas planctônicas foi avaliada a ação antibiofilme sobre as cepas em que foram observadas reduções de viabilidade de 36,7 e 34% para o EG (50 e 25 mg/mL) e 51,3 e 51,4% para EQ (25 e 12,5 mg/mL) contra cepa padrão. As reduções em cepas clínicas variaram de 43 a 73% com EG e de 36 a 79% para EQ. As associações dos extratos promoveram reduções de viabilidade de 8 a 35% contra 5 das 7 cepas clínicas. Conclui-se que os extratos glicólicos de gengibre e quilaia apresentam ação antimicrobiana de forma isolada e combinados com efeito aditivo sobre a forma planctônica de cepas clínicas resistentes de P. aeruginosa. De forma isolada, os extratos apresentaram importante ação preventiva na formação dos biofilmes dessas cepas, podendo ser considerados potenciais fitoterápicos com aplicações terapêuticas para o combate das infecções por P. aeruginosa. (AU)
Plant extracts have demonstrated several positive health effects, including antimicrobial action, however, the clinical use of phytotherapy is still discreet, so that more studies on the beneficial effects of pharmacological synergism of extracts could contribute to its therapeutic application. The aim of this study was to evaluate the effects of glycolic extracts of ginger (EG) and quilaia (EQ) alone and in combination on 7 clinical strains of Pseudomonas aeruginosa and a standard strain in planktonic form and monotypic biofilms. For the antimicrobial analysis on planktonic culture, tests were performed to determine the Minimum Inhibitory Concentration (MIC) and Minimum Microbicidal Concentration (MMC) (CLSI, M07-A9) of the isolated extracts, in addition to the Fractional Inhibitory Concentration Index (FICI) and the Fractionated Microbicidal Concentration Index (FICM) for the combined extracts. Statistical analysis was performed using the ANOVA method and Tukey's test for data with normal distribution and Kruskall-Wallis with Dunn's Multiple Comparison Test for data without normal distribution (5% significance). For the standard strain, MIC were determined equal to 3.12 mg/mL and MMC equal to 6.25 mg/mL for both extracts. For clinical strains the MIC of EG were 3.12 or 6.25 mg/mL and 1.56 or 3.12 mg/mL of EQ, while the MMC values were 6.25 mg/mL for EG and 1.56, 3.12 or 6.25 mg/ml for EQ. The FICI results indicated 15 synergistic and 4 additive associations of the extracts against the standard strain and, among clinical strains, 15 additive results were obtained. From the FICM results, 6 synergistic and 1 additive association against the standard strain were identified, in addition to 8 associations with additive effect against clinical strains. Based on the results of tests on planktonic cultures, the antibiofilm action were evaluated on the strains in which viability reductions of 36 and 34% were observed for EG (50 and 25 mg/mL) and 51% were observed for EQ (25 and 12, 5 mg/mL) against the standard strain. Reductions in clinical strains ranged from 43 to 73% with EG and from 36 to 79% for EQ. Associations of extracts promoted viability reductions of 8 to 35% against 5 out of 7 clinical strains. It is concluded that the glycolic extracts of ginger and quilaia have antimicrobial action in isolation and combined with additive effect on the planktonic form of resistant clinical strains of P. aeruginosa. Isolated, the extracts showed an important preventive action in the formation of biofilms of these strains and may be considered potential herbal medicines with therapeutic applications to combat P. aeruginosa infections. (AU)