Phenolic acid composition, antiatherogenic and anticancer potential of honeys derived from various regions in Greece

PLoS One. 2014 Apr 21;9(4):e94860. doi: 10.1371/journal.pone.0094860. eCollection 2014.

Abstract

The phenolic acid profile of honey depends greatly on its botanical and geographical origin. In this study, we carried out a quantitative analysis of phenolic acids in the ethyl acetate extract of 12 honeys collected from various regions in Greece. Our findings indicate that protocatechuic acid, p-hydroxybenzoic acid, vanillic acid, caffeic acid and p-coumaric acid are the major phenolic acids of the honeys examined. Conifer tree honey (from pine and fir) contained significantly higher concentrations of protocatechuic and caffeic acid (mean: 6640 and 397 µg/kg honey respectively) than thyme and citrus honey (mean of protocatechuic and caffeic acid: 437.6 and 116 µg/kg honey respectively). p-Hydroxybenzoic acid was the dominant compound in thyme honeys (mean: 1252.5 µg/kg honey). We further examined the antioxidant potential (ORAC assay) of the extracts, their ability to influence viability of prostate cancer (PC-3) and breast cancer (MCF-7) cells as well as their lowering effect on TNF- α-induced adhesion molecule expression in endothelial cells (HAEC). ORAC values of Greek honeys ranged from 415 to 2129 µmol Trolox equivalent/kg honey and correlated significantly with their content in protocatechuic acid (p<0.001), p-hydroxybenzoic acid (p<0.01), vanillic acid (p<0.05), caffeic acid (p<0.01), p-coumaric acid (p<0.001) and their total phenolic content (p<0.001). Honey extracts reduced significantly the viability of PC-3 and MCF-7 cells as well as the expression of adhesion molecules in HAEC. Importantly, vanillic acid content correlated significantly with anticancer activity in PC-3 and MCF-7 cells (p<0.01, p<0.05 respectively). Protocatechuic acid, vanillic acid and total phenolic content correlated significantly with the inhibition of VCAM-1 expression (p<0.05, p<0.05 and p<0.01 respectively). In conclusion, Greek honeys are rich in phenolic acids, in particular protocatechuic and p-hydroxybenzoic acid and exhibit significant antioxidant, anticancer and antiatherogenic activities which may be attributed, at least in part, to their phenolic acid content.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antineoplastic Agents / pharmacology
  • Antineoplastic Agents / therapeutic use*
  • Antioxidants / pharmacology
  • Antioxidants / therapeutic use
  • Atherosclerosis / drug therapy*
  • Carbohydrates / analysis
  • Cell Line, Tumor
  • Cell Survival / drug effects
  • Chromatography, High Pressure Liquid
  • Flowers / chemistry
  • Free Radicals / metabolism
  • Furaldehyde / analogs & derivatives
  • Furaldehyde / analysis
  • Greece
  • Honey*
  • Humans
  • Hydroxybenzoates / analysis*
  • Intercellular Adhesion Molecule-1 / metabolism
  • Oxygen / metabolism
  • Plant Extracts / pharmacology
  • Plant Extracts / therapeutic use
  • Reference Standards
  • Tumor Necrosis Factor-alpha / pharmacology
  • Vascular Cell Adhesion Molecule-1 / metabolism

Substances

  • Antineoplastic Agents
  • Antioxidants
  • Carbohydrates
  • Free Radicals
  • Hydroxybenzoates
  • Plant Extracts
  • Tumor Necrosis Factor-alpha
  • Vascular Cell Adhesion Molecule-1
  • Intercellular Adhesion Molecule-1
  • 5-hydroxymethylfurfural
  • Furaldehyde
  • phenolic acid
  • Oxygen

Grant support

Greek Secretariat of Research and Technology, Ministry of Development for financial support (Grant ESPA, SMEs 2009) in cooperation with the company “Attiki” Alex Pittas SA. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. This does not alter the authors’ adherence to PLOS ONE policies on sharing data and materials.