Comparative analysis of the essential oils of three Lamiaceae species obtained by conventional and microwave-assisted hydrodistillation

Abstract

The purpose of this paper is to compare the essential oils (EOs) of three Lamiaceae species (Satureja montana (winter savory), Ocimum basilicum (basil) and Origanum vulgare (oregano)) isolated by hydrodistillation (HD) and microwave-assisted hydrodistillation (MWHD). The total EO yields of all three plants obtained by MWHD were nearly twofold lower than those obtained by HD. However, the microwave treatment was found to be significantly shorter. The chemical profile of the EOs obtained was determined using GC-MS. Carvacrol was the most abundant compound in the winter savory and oregano EOs (92.20 and 93.42 %, respectively), whereas linalool was the predominant compound in the basil EO (67.71 %). The results obtained indicate that certain chemical alterations occur during microwave treatments. The MWHD of winter savory led to a decrease in the carvacrol content (84.11 %), accompanied by a significant increase in the antioxidant activity determined by the DPPH assay, compared to the winter savory EO obtained by HD. Although a decrease in major compound contents of both the basil and oregano EOs obtained by MWHD was observed, no significant difference was found in their antioxidant activity.

Keywords

• lamiaceae
• hydrodistillation
• microwave-assisted hydrodistillation
• essential oil