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Bonvehi J.S.,Research and Development of Nederland Co. | Bermejo F.J.O.,Apinevada Analytical Laboratory of Bee Products
Environmental Monitoring and Assessment | Year: 2013

The aim of this work is to determine the content of essential and toxic elements in 25 raw propolis samples, when considering pollution agents and geographical and botanical factors. The microwave-assisted digestion was the most reliable and accurate method for determination of inorganic elements in propolis samples. The results were obtained using certified reference materials in a good agreement with certified values. Inductively coupled plasma atomic emission spectroscopy was used for the determination of 23 macro- and microelements (Ag, Al, As, B, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, P, Pb, S, Sb, Se, Si, Sn, and Zn). A Mercury analyzer was also utilized for the detection of the total Hg. Among the analyzed metals, Ca, K, Mg, Zn, Si, S, Fe, Al, P, and Na were found to be the most predominant. Heavy metals (As, Cd, Hg, and Pb) were determined in minimal concentration, and Pb was the highest mean contained toxic (<3.80 mg/kg), without influence on provisional tolerable weekly intake values. The method can be applied for routine analysis and quality and environmental pollution controls of toxic elements in propolis samples. The results obtained indicate no pollution of the collection areas and naturally high concentration of Al (460 ± 62.2 mg/kg). © 2012 Springer Science+Business Media Dordrecht. Source


Bonvehi J.S.,Research and Development of Nederland Co. | Gutierrez A.L.,Basque Institute for Agricultural Research and Development
World Journal of Microbiology and Biotechnology | Year: 2012

The antimicrobial activity of 19 propolis extracts prepared in different solvents (ethanol and propylene glycol) (EEP/PEP), was evaluated against some bacterial and fungal isolates using the agar-well diffusion method. It was verified that all the samples tested showed antimicrobial activity, although results varied considerably between samples. Results revealed that both types of propolis extracts showed highly sensitive antimicrobial action against Gram-positive bacteria and fungi at a concentration of 20% (Staphylococcus aureus,Streptococcus mutans, Candida albicans and Saccharomyces cerevisae) with a minimal inhibitory concentration (MIC) ranging from 0.5 to 1.5 mg/ml, with a moderate effect against Streptococcus pyogenes (MIC from 17 to 26 mg/ml). To our knowledge, this is the first study showing elevated antimicrobial activity against Gram-negative bacteria [Salmonella enterica (MIC from 0.6 to 1.4 mg/ml)] and lesser activity against Helicobacter pylori (MIC from 6 to 14 mg/ml), while Escherichia coli was resistant. This concluded that the Basque propolis had a strong and dose-dependent activity against most of the microbial strains tested, while database comparison revealed that phenolic substances were responsible for this inhibition, regardless of their geographical origin and the solvent employed for extraction. Statistical analysis showed no significant differences (P ≤ 0.05) between EEP and PEP extracts. © 2011 Springer Science+Business Media B.V. Source


Bonvehi J.S.,Research and Development of Nederland Co. | Gutierrez A.L.,Basque Institute for Agricultural Research and Development
JAOCS, Journal of the American Oil Chemists' Society | Year: 2011

The purpose of this study was to evaluate the antioxidant activity (AA) of 19 propolis extracts prepared in different solvent (ethanol and propylene glycol). It was observed that all the samples tested had AA, although results varied considerably between extracts, i.e. 420-1,430 μmol Trolox/g (ABTS), 108-291 mg ascorbic acid/g (DPPH), and 1,573-4,669 μmol iron++ sulfate/g (FRAP). The ethanol may enhance the potency of the AA, and the correlation coefficient between total phenolic content (TPC) (200-340 mg/g propolis extracts) and AA was statistically significant. Total flavonoids ranged from 72 to 161 mg/g propolis extracts. The results indicate that TPC and flavonoids contributed to AA. © 2011 AOCS. Source


Kumazawa S.,University of Shizuoka | Bonvehi J.S.,Research and Development of Nederland Co. | Torres C.,Apinevada Analytical Laboratory of Bee Products | Mok-Ryeon A.,Dong - A University | And 2 more authors.
Phytochemical Analysis | Year: 2013

Introduction Propolis is a complex mixture of natural sticky, gummy and resinous components produced by honeybees (Apis mellifera L.) from plant materials. However, phytochemical data of the Andalusian (southern Spain) propolis are scant. Objective The primary objectives of this study were to chemically characterise the compounds and evaluate the anti-oxidant activity found in 28 Andalusian propolis samples. Methods Ethanol extracts of propolis (EEP) were prepared and examined for their anti-oxidant activity by 2,2′-azinobis(3-ethylbenzothiazoline-6-sulphonic acid) and 2,2-diphenyl-1-picrylhydrazyl assays. To characterise the phenolic composition, the presence of 11 compounds was identified by HPLC analysis with photodiode array and mass spectrometric detection. Results All propolis samples had strong anti-oxidant activity, accompanied by high total phenolic content. The most abundant compounds were flavonoids. Concerning the phenolic compounds content, our results showed that the 75% of the samples analysed contained at least 80 mg/g of flavonoids, primarily pinobanksin 3-acetate, pinocembrin, chrysin, galangin and pinobanksin. Caffeic acid phenethyl ester was detected in almost all EEP samples but in smaller proportions (mean 12.9 ± 2.8 mg/g). Conclusion The present investigation constitutes the first comprehensive report on the phenolics identified in southern Spanish propolis. The results revealed that the samples tested showed a high scavenging activity and therefore indicate the possible use of Andalusian propolis as an important source of natural anti-oxidants. Copyright © 2013 John Wiley & Sons, Ltd. Source

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