Which material is the active component of zinc oxide-eugenol (ZOE) cement that provides the obtundent (sedative) effect on the dental pulp?

In zinc oxide-eugenol (ZOE) cement, eugenol (the liquid component, derived from clove oil) is responsible for the obtundent, sedative, and anti-inflammatory effect on the dental pulp. Eugenol inhibits prostaglandin synthesis and has local anesthetic properties, reducing pulpal pain. Zinc oxide (the powder component) provides the setting reaction and structural base. ZOE is used as a temporary restoration material, pulp-capping agent, cavity liner, and endodontic sealer. Note: eugenol can be cytotoxic in high concentrations and may interfere with polymerization of composite resins; ZOE should not be placed beneath composite restorations.