Assessment of the antioxidant and antibacterial activities of different olive processing wastewaters

PLoS One. 2017 Sep 5;12(9):e0182622. doi: 10.1371/journal.pone.0182622. eCollection 2017.

Abstract

Olive processing wastewaters (OPW), namely olive mill wastewater (OMW) and table-olive wastewaters (TOW) were evaluated for their antibacterial activity against five Gram-positive and two Gram-negative bacteria using the standard disc diffusion and thin layer chromatography (TLC)-bioautography assays. Disc diffusion screening and bioautography of OMW were compared to the phenolic extracts of table-olive brines. Positive activity against S. aureus was demonstrated. The optimization of chromatographic separation revealed that hexane/acetone in the ratio of 4:6 was the most effective for phenolic compounds separation. A HPLC-MS analysis was performed showing that only two compounds, hydroxytyrosol and tyrosol, were the predominant phenolic compounds in all OPW. The phenolic extract of OMW generated by a semi-modern process showed the highest free radical-scavenging activity (DPPH assay) compared to the other phenolic extracts. It is apparent from the present study that OPW are a rich source of antioxidants suitable for use in food, cosmetic or pharmaceutical applications.

MeSH terms

  • Anti-Bacterial Agents / pharmacology*
  • Antioxidants / pharmacology*
  • Biphenyl Compounds / chemistry
  • Chromatography, High Pressure Liquid
  • Chromatography, Thin Layer
  • Inhibitory Concentration 50
  • Mass Spectrometry
  • Microbial Sensitivity Tests
  • Olea / chemistry*
  • Phenols / chemistry
  • Picrates / chemistry
  • Staphylococcus aureus / drug effects
  • Wastewater / chemistry*

Substances

  • Anti-Bacterial Agents
  • Antioxidants
  • Biphenyl Compounds
  • Phenols
  • Picrates
  • Waste Water
  • 1,1-diphenyl-2-picrylhydrazyl

Grants and funding

Authors acknowledge Averroès Fellowship Program (funded by the European Commission within the framework of Erasmus Mundus) for funding the research stay of Dr. Majdouline Belaqziz in Waterford (Ireland). As well, Prof. Abdelilah El Abbassi greatly thanks the International Foundation for Sciences (IFS, Sweden) for their financial support under the grants number W4749-1 and W4749-2. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.