Membrane and DNA damaging/protective effects of eugenol, eucalyptol, terpinen-4-ol, and camphor at various concentrations on parental and drug-resistant H1299 cells

Eugenol, eucalyptol, terpinen-4-ol, and camphor, used as flavor agents in cosmetic and food products, have both prooxidant and antioxidant activities. To clarify the mechanisms of their cytotoxic effect and the factors affecting their antioxidant/prooxidant activities, we investigated cell membrane and DNA damage/protective effects induced by eugenol, eucalyptol, terpinen-4-ol, and camphor in parental and drug-resistant human lung cancer cell lines. The parental cells were found approximately 3, 6, and 8 times more sensitive to camphor cytotoxicity than drug-resistant cells at 24, 48, and 72 h respectively. The cytotoxic activity for both cell types was found to be in the order of camphor, eugenol, terpinen-4-ol, and eucalyptol, depending on their concentrations. Malondialdehyde and 8-hydroxy deoxyguanosine levels were also increased as a result of membrane and DNA damage in both cell lines exposed to the highest concentration of these test components. On the other hand, eugenol, eucalyptol, terpinen-4-ol, and camphor protected the cells against H2O2-induced cytotoxicity, membrane damage, and DNA damage when the cells were incubated with these test components at lower concentrations (< IC50) before H2O2 treatment. These findings suggest that eugenol, eucalyptol, terpinen-4-ol, and camphor exhibit membrane and DNA protective/damaging effects changing in a manner dependent upon concentration, cell type, and time.