Poster Topical Area: Dietary Bioactive Components
Location: Hall D
Poster Board Number: 293
Objective: There is growing interest to identify natural antioxidant substance for use in animal feed and human food. The current study aimed to evaluate antioxidant properties of essential oils from peppermint, spearmint and scotch spearmint.
Methods: Three mint oils produced through re-distillation process were evaluated for their antioxidant activity in vitro. The antioxidant properties in terms of free radical scavenging, ferric iron reduction and hydrogen-donating were evaluated through four chemical-based assays, namely DPPH radical scavenging assay (DPPH), Trolox equivalent antioxidant capacity assay (TEAC), reducing power assay, and ferric reducing antioxidant power assay (FRAP). The inhibitory capacity of mint oils against lipid peroxidation was tested at various doses using fresh pig liver homogenates with or without the presence of oxidants. At last, a porcine jejunum epithelial cell line (IPEC-J2) was employed to determine the impact of adding mint oils at different concentrations on cellular antioxidant activity and ratio of oxidized and reduced glutathione. All data were analyzed by PROC MIXED of SAS. CONTRAST statement was used to assess linear or quadratic effects of mint oils given at various doses.
Results: Mint oils all exhibited potent antioxidant activity in chemical based assays. Peppermint oil had the lowest (P < 0.05) half maximal effective concentration in DPPH and TEAC assay and the highest reducing capacity in FRAP and reducing power assays as compared with the other two mint oils. All mint oils displayed inhibitory effect on lipid peroxidation in a dose-dependent manner (linear, P < 0.001) with the lowest lipid peroxidation observed at 1,000 µg/mL. Mint oils significantly increased the death of IPEC-J2 when the concentration in culture medium reached 200 µg/mL. The maximal cellular antioxidant activity was observed at 5 µg/mL for peppermint oil, and 100 µg/mL for spearmint oil and scotch oil. The addition of 25 µg/mL of spearmint oil or scotch oil increased (P < 0.05) the production of glutathione from H2O2-treated IPEC-J2 cells.
Conclusions: Three essential oils all demonstrated antioxidant activities in both chemical- and cell-based assays. Appropriate dose of mint oil is critical to inhibit oxidative response without damage cell viability.
Dept. Nutrition at University of California Davis