Influence of olive leaf processing on the bioaccessibility of bioactive polyphenols

J Agric Food Chem. 2014 Jul 2;62(26):6190-8. doi: 10.1021/jf501414h. Epub 2014 Jun 24.

Abstract

Olive leaves are rich in bioactive compounds, which are beneficial for humans. The objective of this work was to assess the influence of processing conditions (drying and extraction) of olive leaves on the extract's bioaccessibility. Thus, extracts obtained from dried olive leaves (hot air drying at 70 and 120 °C or freeze-drying) by means of conventional or ultrasound-assisted extraction were subjected to in vitro digestion. Antioxidant capacity, total phenolic content, and HPLC-DAD/MS/MS analysis were carried out during digestion. The dehydration treatment used for the olive leaves did not have a meaningful influence on bioaccessibility. The digestion process significantly (p<0.05) affected the composition of the extracts. Oleuropein and verbascoside were quite resistant to gastric digestion but were largely degraded in the intestinal phase. Nevertheless, luteolin-7-O-glucoside was the most stable polyphenol during the in vitro simulation (43% bioaccessibility). Therefore, this compound may be taken into consideration in further studies that focus on the bioactivity of olive leaf extracts.

Keywords: Olea europaea; antioxidant potential; byproduct; drying; in vitro digestion.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Agriculture / economics
  • Antioxidants / analysis
  • Antioxidants / economics
  • Antioxidants / isolation & purification
  • Antioxidants / metabolism*
  • Dietary Supplements / analysis
  • Dietary Supplements / economics
  • Digestion*
  • Food Handling
  • Glucosides / analysis
  • Glucosides / economics
  • Glucosides / isolation & purification
  • Glucosides / metabolism
  • Humans
  • Hydrolysis
  • Industrial Waste / analysis
  • Industrial Waste / economics
  • Iridoid Glucosides
  • Iridoids / analysis
  • Iridoids / economics
  • Iridoids / isolation & purification
  • Iridoids / metabolism
  • Luteolin / analysis
  • Luteolin / economics
  • Luteolin / isolation & purification
  • Luteolin / metabolism
  • Models, Biological*
  • Olea / chemistry*
  • Phenols / analysis
  • Phenols / economics
  • Phenols / isolation & purification
  • Phenols / metabolism
  • Phytochemicals / analysis
  • Phytochemicals / economics
  • Phytochemicals / isolation & purification
  • Phytochemicals / metabolism*
  • Plant Extracts / chemistry
  • Plant Extracts / economics
  • Plant Extracts / isolation & purification
  • Plant Extracts / metabolism*
  • Plant Leaves / chemistry*
  • Spain

Substances

  • Antioxidants
  • Glucosides
  • Industrial Waste
  • Iridoid Glucosides
  • Iridoids
  • Phenols
  • Phytochemicals
  • Plant Extracts
  • oleuropein
  • acteoside
  • luteolin-7-glucoside
  • Luteolin