Antioxidant activity of fractions from oregano essentials oils obtained by molecular distillation

Abstract

The objective of this study was to determine the antioxidant activity of fractions separated from oregano essential oil by short-path molecular distillation. Two residue (R1 and R2) and two distillate (D1 and D2) fractions were prepared by molecular distillation. The major components were: carvacrol, terpinen-4-ol, and γ-terpinene in R1 and R2; and γ-terpinene, α-terpineol, and sabinene in D1 and D2. Free-radical scavenging activities was observed in all fractions and was higher in R2 (77.23%). D1 and D2 showed less amount of volatile oxidation compounds produced from sunflower oil stored at 60 ºC for 14 days. The greatest antioxidant activity was observed in D1 and D2. Thermal stability was also analyzed in oregano essential oil and fractions. Oregano essential oil, R1 and R2 presented higher carvacrol concentration and thermal stability. The short-path molecular distillation fractions can be used to prepare fractions from oregano essential oil with higher antioxidant activity.