Treatment with 0.1% oregano inhibited lipid oxidation to the same extent as rosemary (alone or with ascorbic acid).
However,when oregano was used at a lower concentration (0.02%), the antioxidant effect was significantly lower (p < 0.01); therefore, there was a concentration-dependent effect.
Oregano, which belongs to the same family as rosemary, contains also a number of phenolic compounds, rosmarinic acid being the most abundant.