engleski

Galangin expresses bactericidal activity against multiple-resistant bacteria: MRSA, Enterococcus spp. and Pseudomonas aeruginosa

The antimicrobial activity of three propolis ethanol extracts (EEP) was examined for various Gram-negative and Gram-positive bacterial species, including multiple-resistant Staphylococcus aureus, Enterococcus spp. and Pseudomonas aeruginosa strains. EEP had a good bactericidal activity against Gram-positive species, and all multiple-resistant bacterial strains tested were sensitive to EEP. Minimal inhibitory concentrations (MICs) were lower in samples of higher flavonoid content (from 0.65 to 7.81 mg mL-1), indicating the influence of the concentration of some potent bactericidal compound(s) in propolis or synergism among some bactericidal compounds. Antimicrobial-guided separation of flavonoid aglycones (bioassay in situ on thin-layer chromatogram) showed that galangin (3, 5, 7-trihydroxyflavone) is one compound in EEP with bactericidal activity. Galangin was isolated by preparative chromatography. After determining the quantity present, the MIC against multiple-resistant bacteria was determined. The MIC of galangin against multiple-resistant bacterial strains was significantly lower (from 0.16 to 0.44 mg mL-1, p < 0.05) than that of EEP. The bactericidal activity of galangin against P. aeruginosa strains was present at 0.17 &plusmn ; ; 0.05 mg mL-1.

Galangin; 3; 5; 7-Trihydroxyflavone; Flavonoids; Bacteria; Resistance; Staphylococcus aureus; Enterococcus spp.; Pseudomonas aeruginosa

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