Essential oils of Origanum vulgare L. subsp. glandulosum (Desf.) Ietswaart from Tunisia: chemical composition and antioxidant activity

J Sci Food Agric. 2010 Aug 15;90(10):1745-9. doi: 10.1002/jsfa.4011.

Abstract

Background: Characterisation of the essential oils from O. glandulosum collected in three locations of Tunisia, chemical composition and the evaluation of their antioxidant activities were carried out.

Results: The essential oils from Origanum vulgare L. subsp. glandulosum (Desf.) Ietswaart collected from three localities of north Tunisia-Krib, Bargou and Nefza-were obtained in yields of 2.5, 3.0 and 4.6% (v/w), respectively. The essential oils were analysed by GC and GC/MS and assayed for their total phenolics content, by the Folin-Ciocalteu method, and antioxidant effectiveness, using the 2,2-diphenyl-1-picrylhydrazil (DPPH) radical scavenging assay. The main components of these essential oils, from Nefza, Bargou and Krib, were p-cymene (36%, 40% and 46%), thymol (32%, 39% and 18%), gamma-terpinene (24%, 12% and 16%) and carvacrol (2%, 2% and 15%), respectively). The ability to scavenge the DPPH radicals, expressed by IC(50), ranged from 59 to 80 mg L(-1). The total phenolic content, expressed in gallic acid equivalent (GAE) g kg(-1) dry weight, varied from 9.37 to 17.70 g kg(-1) dw.

Conclusions: A correlation was identified between the total phenolic content of the essential oils and DPPH radical scavenger capacity. The occurrence of a p-cymene chemotype of O. glandulosum in the northern region of Tunisia is demonstrated.

MeSH terms

  • Antioxidants / analysis
  • Antioxidants / pharmacology*
  • Biphenyl Compounds
  • Oils, Volatile / chemistry
  • Oils, Volatile / pharmacology*
  • Origanum / chemistry*
  • Phenols / analysis
  • Phenols / pharmacology*
  • Picrates
  • Plant Extracts / chemistry
  • Plant Extracts / pharmacology*
  • Tunisia

Substances

  • Antioxidants
  • Biphenyl Compounds
  • Oils, Volatile
  • Phenols
  • Picrates
  • Plant Extracts
  • 1,1-diphenyl-2-picrylhydrazyl