Bioactive compounds and antioxidant activity of essential oils of <i>Origanum dictamnus</i> from Mexico

The quality and content of essential oils extracted from medicinal and culinary plants can be affected by harvesting time conditions. This study focused on the antioxidant activity and chemical composition of Origanum dictamnus essential oils under different harvesting time conditions. Samples from the same area and different harvesting times were treated by hydrodistillation. Gas Chromatography (GC-FID) and gas chromatography-mass spectrometry (GC-MS) were used to determine the different compounds found in essential oils. In all the essential oil samples, the phenolic monoterpenoid Carvacrol was prevalent. Through different seasons, we could observe a relatively high yield ratio. However, the lowest and highest yield values were found in plants collected during winter and summer. These essential oils showed high level radical scavenging properties level, as exhibited in the DPPH assay. Essential oils from sample C (collected on 10/02/18) showed the highest antioxidant activity.