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

The inhibitory effects of Zataria multiflora essential oil on nitric oxide (NO) and hydrogen peroxide (H₂O₂) production were examined in human monocytes cultured in the presence of 20 mM glucose. Z. multiflora essential oil was extracted by water-distillation and then analyzed by GC–MS. Carvacrol (29.2%), thymol (25.4%), p-cymene (11.2%), linalool (9.6%) and γ-terpinene (8%) were the main components detected in the essential oil. Cells cultured in the presence of 20 mM glucose showed an increase in NO and H₂O₂ production as well as NO synthase (NOS) and NADH oxidase (NOX) activities compared to cells cultured in the presence of 5 mM glucose. Pretreatment with Z. multiflora essential oil, carvacrol and thymol reduced NO and H₂O₂ production as well as NOS and NOX activities in those cells cultured in the presence of 20 mM glucose. However, p-cymene, linalool and γ-terpinene did not show any such activities. Accordingly, it was concluded that Z. multiflora can reduce oxidative stress and can be used in the therapy of oxidative damage accompanying hyperglycemia and some inflammatory conditions.