The emulsion made with essential oil and aromatic water from Oliveria decumbens protects murine macrophages from LPS-induced oxidation and exerts relevant radical scavenging activities

Oliveria decumbens Vent., is an endemic plant of Iran belonging to the Apiaceae family, where it grows in the arid southeastern regions. In the traditional medicine, it is used in cases of indigestion, diarrhea, abdominal pain and fever. An nanoemulsion including polysorbate (100 µg/mL), Oliveria decumbens essential oil (OEO, 1 mL) and O. decumbens aromatic water (OAW, 100 mL) was prepared. The radical scavenging and antioxidant capacity of OEO-OAW emulsion was investigated in lipopolysaccharide (LPS)-stimulated murine macrophages. The reduction of nitric oxide (NO), intracellular reactive oxygen species (ROS), and thiobarbitoric acid reactive substances (TBARS) at non-cytotoxic concentrations (< 3000 ng/mL) of OEO-OAW was determined. The main components of OEO were thymol (25.5%), carvacrol (23.1%), p-cymene (22.1%) and γ-terpinene (17.8%). The emulsion exhibited 1,1-diphenyl-2-picryl-hydrazyl radical (DPPH), 2,2-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) radical (ABTS), superoxide radical (O2-), hydrogen peroxide (H2O2), hydroxyl radical (HO), NO, nitrite (NO2) and malondialdehyde (MDA) scavenging effects as well as lipid oxidation inhibition at low concentrations (20–200 µg/mL). In addition, at lower doses (1000–3000 ng/mL) it strongly reduced formation of NO, ROS and TBARS in LPS-stimulated macrophages. Taken together, our outcomes corroborate the antioxidant properties of O. decumbens formulation and provide new insights into the industrial and pharmacological properties of OEO-OAW.