The more prominent effect of EEPs against gram-positive than against gram-negative bacteria, as assessed by the MIC assay, agrees with previous studies that have shown that propolis from stingless bees (7,9,23) and from Apis mellifera (6) has antimicrobial activity, particularly against gram-positive bacteria.
Therefore, we decided to comparatively assess the antioxidant activity and total content of phenols and flavonoids in the EEPs from M.
In addition, EEPs were more effective against gram-positive than against gram-negative strains, especially against S.
Was found that all propolis extracts showed inhibitory action against the Staphylococcus strains evaluated MIC90 = 60 - 30 mg/mL, and the average MICs (mg/mL) for each EEP were: EEP1 = 11.88+-4.98; EEP2 = 31.25+-16.71; EEP3 = 51.25+-21.43; EEP4 = 22.81+-11.88; EEP5 = 17.50+-10.25.
The propolis extracts (EEP) were numbered according to the obtaining region, as follow: EEP 1 from Fusagasuga - Cundinamarca; EEP 2 from Une - Cundinamarca; EEP 3 from San Luis - Antioquia; EEP 4 Betania - Antioquia and EEP 5 from Garzon - Huila.
Of eighty-four registered EEPs, forty-six (55 percent) are former governmental officials while fourteen (17 percent) are serving officials.
Several reform-minded EEPs have noticed this problem.
All effects of the EEPs were compared with negative controls.
In the assay with the ABTS radical, IC50 values of the EEPs were 80.04 [+ or -] 0.31 [micro]g/mL (EEP-S) and 13.45 [+ or -] 1.81 [micro]g/mL (EEP-M), and they showed maximal activity at concentrations of 200 [micro]g/mL and 100 [micro]g/mL, respectively.
2,2-Diphenyl-1-Picrylhydrazil (DPPH) radical scavenging assay: The free-radical scavenging activities of the samples' EEP, ethyl acetate fraction, water soluble fraction extract as well as vitamin C tested as bleaching of the stable DPPH according to the method by Matsushige et al.
The mixture was then dosed separately with 0.2 ml of the extracted propolis fractions of hexane, ethyl acetate and water as well as EEP made by dissolving these fractions in methanol/chloroform (1:2 v/v) .