Inhibitory effects of Zataria multiflora essential oil and its main components on nitric oxide and hydrogen peroxide production in lipopolysaccharide-stimulated macrophages

Objectives Zataria multiflora is an aromatic plant that is used in flavouring and preserving foods and also used as an antispasmodic, anaesthetic and antinociceptive agent. In this study, the effects of Z. multiflora essential oil on nitric oxide (NO) and hydrogen peroxide (H2O2) production in lipopolysaccharide (LPS)-stimulated macrophages was investigated. Methods Z. multiflora essential oil was extracted by water-distillation, analysed by GC-MS and then the effect of the essential oil on NO and H2O2 production was investigated. Key findings Carvacrol (52%), thymol (16%) and p-cymene (10%) were the main components of the oil. The IC50 (concentration providing 50% inhibition) for reactive oxygen scavenging was estimated to be 5.7, 3 and 4.2 mu g/ml for the essential oil, thymol and carvacrol, respectively, while the corresponding IC50 values for reactive nitrogen scavenging were estimated to be 8.6, 4.7 and 6.6 mu g/ml. Z. multiflora essential oil, thymol, and carvacrol significantly reduced NO and H2O2 production as well as NO synthase and NADH oxidase activity in LPS-stimulated murine macrophages while p-cymene did not show any antioxidant activity. Conclusions Z. multiflora essential oil has the potential to be used in the therapy of oxidative damage.