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Antioxidant-related parameters and anti-inflammatory and antimicrobial activities against Listeria monocytogenes were assessed in eight North East Spain poplar propolis samples. Propolis extracts (PEs) were obtained using 70% ethanol (PEE) and methanol (PME). Yield and total phenol compounds were higher in PEE. Phenolic acids were analyzed by a high-performance liquid chromatograph–diode array detector. Caffeic and ferulic acids were quantified in all PEE and PME. All samples contained p-coumaric acid (quantified in 6 PEE and in 3 PME). Ascorbic acid was detected in all propolis, but mainly quantified in PME (≤0.37 mg/g PE). Biological properties were tested on PEE. As for antiradical activities, trolox equivalent antioxidant capacity (TEAC) [against 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)•+], ranged between 578 and 4620 µmol trolox/g, 2,2-diphenyl-1-picrylhydrazyl (DPPH) (against DPPH free radical), between 0.049 and 0.094 mg/mL, antioxidant activity against hydroxyl (•OH) radical (AOA), between 0.04 and 11.01 mmol uric acid/g, and oxygen radical absorbance capacity (ORAC) against peroxyl (ROO•) radical between 122 and 3282 µmol trolox/g. Results of TEAC, AOA, and ORAC were significantly correlated. IC50 anti-inflammatory activity ranged from 1.08 to 6.19 mg/mL. Propolis showed higher inhibitory activity against L. monocytogenes CECT934 and L. monocytogenes CP101 by agar well diffusion (P <.05) (10.5 and 10.2 mm, respectively) than against L. monocytogenes CP102 (7.0 mm). Data of this research show that North East Spain propolis may be of interest for pharmaceutical and food industry use. [ABSTRACT FROM AUTHOR]

This study was aimed to assess quality, authentication parameters and trolox equivalent antioxidant capacity (TEAC) of Algerian and imported honeys sold in Algerian markets. Results indicated that 80% Algerian samples fulfilled international standards, whereas only 21.4% imported honeys were in agreement with the current regulations. 13.3% Algerian samples and 7.1% imported honeys showed values of proline lower than 180 mg/kg, which is the recommended limit for authentic honeys. Comparing Algerian and imported honeys, electrical conductivity, degrees Brix, diastase activities and proline contents were higher in Algerian honeys, in contrast to moisture percentages, hydroxymethylfurfural contents and acid phospatase activities that were higher in imported honeys. Methanolic extracts of Algerian samples were richer both in total phenolics and flavonoids determined in alkaline medium. There were not significant differences between Algerian and imported samples concerning pH, free acid, invertase, total carotenoid, total phenolics of raw honeys and TEAC, as well as regarding total flavonoids determined in neutral medium and o-diphenols of honeys’ methanolic extracts. Principal components analysis showed a good separation between Algerian and imported samples, only one multifloral Algerian honey being misclassified. Our research showed that a legal frame for Algerian honeys is of utmost importance. Spurge-labeled honeys were grouped, showing interesting common features that should be taken into account in a future regulation, in which a protected designation of origin for spurge honeys could be considered.

Polyphenols are secondary plant metabolites playing a major role as potentially functional components. They can also be used for honey authentication. This review gathers the recent literature references about honey extraction procedures, as well as instrumental analysis of phenolic compounds found in honey. Liquid-Liquid extraction is widely used for both extraction and purification purposes, with adequate recovery percentages. However, the use of high solvent volumes is a major disadvantage. More environmentally friendly methods include accelerated solvent extraction, and dispersive and inverse dispersive liquid-liquid microextraction. Solid phase extraction is the most common method for honey polyphenols’ isolation. Polyphenol isolation by a combination of liquid-liquid and solid phase extraction allows good recoveries for a variety of different compounds. High-performance liquid chromatography with ultraviolet or mass spectrometry detectors is by far, the most commonly employed instrumental procedure to separate and quantify polyphenols in honey although capillary electrophoresis has been also successfully used for these purposes. The use of new sorbents, the optimization of current procedures and the development of other simple and rapid analytical techniques are challenges for future analysis of polyphenols found in honey. [ABSTRACT FROM AUTHOR]