ISLA Maria Ines
congresos y reuniones científicas
Antimicrobial efficacy of polyphenols from Rosmarinus officinalis L. against human pathogenic bacteria.
La Valette- Malte.
Congreso; 3rd International Conference & Exhibition on Polyphenols Applications in Food, Pharmaceutical and Cosmetic Industries; 2006
Institución organizadora:
Universidad de Malta. Sociedad Japonesa de Antioxidantes.
Rosmarinus officinalis (rosemary) are plant species widespread in the world. In recent years numerous investigations have been centered in the isolation of its bioactive components. Although, it is clear that rosemary extracts have bioactive properties according to traditional use and scientific evidence, studies about the antimicrobial activities of non-volatile compounds as well as regarding the interactions with other known compounds are limited. We described previously that several rosemary extracts were effective antimicrobial agents against Gram positive and Gram-negative bacteria and yeast (Free Radical Research, 40 (2) 223-231, 2006). The antioxidant and antimicrobial activity of them was related to phenolic composition such as cafeic acid derivates and diterpenes phenolic. This work report a further study of the antimicrobial properties of rosemary extracts and purified compounds from plants collected in Argentina in order to identify antimicrobial bioactive compound/s. Several Gram positive and negative bacteria were tested by the agar diffusion assay and agar macrodilution/broth microdilution methods according to NCCLS 2002. Plant extract and/or pure compound were assayed against sensible and multi-resistant antibiotic human pathogenic bacteria isolated from clinical samples obtained from the Hospital Nicolas Avellaneda, Tucum├ín, Argentina. The assayed strains were S. aureus (n=3), E. faecalis (n=13), E. coli (n= 7), K. pneumoniae  (n= 2), P. mirabilis (n= 3), E. cloacae (n=3 ), M. morganii (n=1), P. aeruginosa (n=2 ) and four reference strains were included in the study, S. aureus ATCC 29213,  E. faecalis ATCC 29212, E. coli ATCC  35218, E.coli ATCC  25922,  25923, K. pneumoniae ATCC 700603. Our results showed that rosmarinic extract, carnosic and rosmarinic acid isolated from them were able to inhibit the growth of antibiotic multi-resistant human pathogenic bacteria. Here, we also look for synergism of the plant compounds with common compounds to inhibit pathogenic microorganisms. A promising strategy to enhance and/or enlarge the biological activity such as antioxidant and antimicrobial activities seems to be the combination of two or more compounds. Our results indicate that rosemary compounds improve the antioxidant properties of synthetic antioxidant such as butyl hydroxyanisole and butylated hydroxytoluene. We found also that rosemary extract showed a clear potentiation on the antimicrobial action in mix with butyl hydroxyanisole against Escherichia coli and Staphylococcus aureus. A different specificity and efficacy in the antimicrobial activity for rosmarinic acid and carnosic acid, was observed. All these results indicated that carnosic acid and rosmarinic acid are important bioactive compounds implicated in the antibacterial properties of the rosemary extract. From a practical point of view Argentinean rosemary extract may be a good candidate for functional foods and pharmaceutical products.