To investigate antioxidant effects of tea tree root extracts using various extraction methods, cytotoxicity, DPPH and ABTS radical scavenging, SOD, nitrite scavenging activity and inhibitory activity of lipid peroxidation, reducing power, ferrous ion chelating activity were measured. Cytotoxicity for RAW 264.7 cells was not observed at concentrations treated with below 90 μg/mL in all extracts. The maximum DPPH radical, nitrite scavenging, SOD activity and inhibitory activity of lipid peroxidation were obtained at the ethylacetate and 70% ethanol extract. The maximum ABTS radical scavenging activity was obtained at the ethylacetate and hot water extract. However, in the case of reducing power and ferrous ion chelating activity, they were obtained at 70% ethanol and hexane extract, respectively. Nitrate scavenging activity showed the most excellent scavenging ability of 59.6% at 90 μg/mL of ethylacetate. The hexane extract had the highest ferrous ion chelating activity, showing 61.05% at 50 μg/mL, 66.07% at 70 μg/mL and 76.81% at 90 μg/mL, respectively. The results of this research show that the ethylacetate and 70% ethanol extracts of tea tree root can be used as a natural material for scavenging the radicals. However, future study is necessary to understand the mechanism of antioxidant activity by identification of substances.

Abstract
Introduction
Material and Method
    1. Extracts preparation and reagents
    2. Cell viability
    3. Measurement of DPPH radical scavenging activity
    4. Measurement of ABTS radical scavenging activity
    5. Measurement of superoxide dismutase activity
    6. Measurement of reducing power
    7. Measurement of inhibitory activity on lipid peroxidation
    8. Measurement of ferrous ion chelating activity
    9. Nitrite scavenging activity
Result and Discussion
    1. Cell viability
    2. DPPH radical scavenging activity
    3. ABTS radical scavenging activity
    4. Superoxide dismutase activity
    5. Reducing power
    6. Lipid peroxidation inhibition
    7. Nitrate scavenging activity
    8. Ferrous ion chelating activity
    9. Correlation
Conclusion
Acknowledgment
References

• Hyun-suk Choi(Associate Professor, Dept. of Hotel Culinary Arts Patissier & Nutrition, Chungcheong University, Chungju 28171, Korea)
• Myung-ja Lee(Director, Korean Tea Culture Federation (Incorporated Association), Changwon 51764, Korea)
• So-young Kwak(Doctor Course, Dept. of Medical Sciences, Graduate School of Nambu University, Gwangju 62271, Korea)
• Dubok Choi(Professer, Faculty of Advanced Industry Convergence, Chosun University, Gwangju 61452, Korea) Corresponding author