RESUMO

In this paper we investigated the antibacterial activity of a methanolic extract of Rosmarinus officinalis L. and their main constituents, carnosic acid and rosmarinic acid, against 37 nosocomial strains of multidrug-resistant bacteria. Results obtained showed that both the rosemary extract and carnosic acid inhibited all clinical isolates of Staphylococcus aureus methicillin-resistant and Enterococcus faecalis gentamicin and streptomycin-resistant bacteria examined (MICs 60 ug/mL vs. 200 ug/mL, respectively). Rosemary extract showed MIC values between 400 and 1600 ug/ml against the Gram-negative multidrug-resistant bacteria: Escherichia coli, Proteus mirabilis, Enterobacter cloacae, Pseudomonas aeruginosa, Morganella morganii and Providencia stuartii, while carnosic acid showed MIC of 120 to 240 ug/mL. Bactericidal effect of carnosic acid against S. aureus and E. faecalis was observed at their MIC value, while 2 x MIC to 4 x MIC were needed to kill Gram-negative bacteria. Rosmarinic acid showed a narrow spectrum of action against a few Gram-negative clinical isolates. Our findings suggest that carnosic acid would be a good lead candidate useful in counteracting drug-resistant infections.

En este trabajo evaluamos la actividad antibacteriana de un extracto metanólico de Rosmarinus officinalis L. y sus principales componentes el ácido carnósico y ácido rosmarínico, contra 37 cepas de bacterias multirresistentes nosocomiales. Los resultados muestran que el extracto de romero y el ácido carnósico, inhibieron las bacterias Gram-positivas Staphylococcus aureus resistentes a meticilina y Enterococcus faecalis resistentes a gentamicina y estreptomicina (CIM 200 ug/mL y 60 ug/mL, respectivamente). El extracto de romero inhibió los Gram negativos multirresistentes: Escherichia coli, Proteus mirabilis, Enterobacter cloacae, Pseudomonas aeruginosa, Morganella morganii y Providencia stuartii (CIM 400 a 1600 ug/mL), mientras que el ácido carnósico mostró valores de CIM entre 120 a 240 ug/mL. El ácido carnósico mostró actividad bactericida contra S. aureus y E. faecalis a su CIM, mientras que 2 a 4 X CIM se requirieron para matar las bacterias Gram-negativas. El ácido rosmarínico mostró inhibió unos pocos aislados clínicos Gram-negativos. Estos hallazgos sugieren que el ácido carnósico puede ser de utilidad contra infecciones bacterianas multirresistentes a antibióticos.

Assuntos

RESUMO

The antimicrobial and antioxidant activities of standardized extracts of Baccharis incarum in 60° and 80° ethanol and of a phytopharmaceutical formulation obtained from them were measured. Baccharis tinctures showed antimicrobial activity against clinically isolated antibiotic resistant Staphylococcus aureus and Enterococcus faecalis, with MIC values of 40-80 µg GAE/mL. Both tinctures exhibited ABTS(●+) scavenging activity with SC(50) values between 1.6 and 4.0 µg GAE/mL. The tinctures were not genotoxic in the Salmonella assay. For this reason, the tincture in 60° ethanol was incorporated into a topical pharmaceutical formulation (Hydrogel/ Carbopol® 934). The phytopharmaceutical formulation also showed antibacterial and antioxidant activities in the in vitro assays. The hydrogel showed microbiological, chemical, physical and functional stability during storage at room temperature. Studies that measure drug release as a determination of bioavailability were also carried out using the Franz diffusion cell (FC). The results demonstrated the release of two bioactive compounds (chlorogenic acid and 4',5-dihydroxy-3',3,6,7,8-pentamethoxyflavone) from the phytotherapic preparation in HPLC studies of FC receptor solution. In consequence, the phytopreparation applied topically could be used to treat skin and soft tissue infection produced by methicillin-resistant Staphylococcus aureus (MRSA) or Enterococcus faecalis and opens new opportunities for the use of active natural ingredients in the cosmeceutical field as antiacne and antioxidant.

Assuntos