Assessment of in vitro antioxidant activity of essential oil of Eucalyptus citriodora (lemon-scented Eucalypt; Myrtaceae) and its major constituents

We investigated the chemical composition and antioxidant activity of Eucalyptus citriodora (lemon-scented eucalyptus) leaf oil in terms of total antioxidant activity, ferric reducing antioxidant power (FRAP) assay, ferrous ion chelating activity, and scavenging of hydrogen peroxide (H2O2) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals and inhibition of lipid peroxidation. GC-MS analysis of essential oil revealed the presence of 43 components constituting 99.2% of oil. The oil was monoterpenoid (94.35% of oil) with citronellal (60.66%), β-citronellol (12.58%) and isopulegol (8.19%) as the major monoterpenoids. Oil and its major monoterpenes exhibited moderate to strong antioxidant activity in terms of TAA, FRAP and Fe+2 chelating, DPPH and H2O2 scavenging, and lipid peroxidation inhibition. The study concludes that E. citriodora leaves contain monoterpenoid rich oil exhibiting antioxidant activity.

► We examined composition and antioxidant activity of Eucalyptus citriodora leaf oil. ► The oil was monoterpenoid in nature with citronellal (∼61%) as the major component. ► Oil and major constituents exhibit TAA, Fe+2 chelating and radical scavenging capacity. ► Citronellal possess greater FRAP, H2O2 scavenging activity than the crude oil. ► Isopulegol had greater TAA activity compared to the oil.