This study analyzed the antioxidant properties of Equisetum arvense and its effects on serum factor levels in mice fed a high-fat diet. The aim was to establish a new effective resource for biologically active materials. E. arvense stem and root extracts were obtained using deionized water at 95℃, and 70.5% ethanol at 85℃. These extracts were used to analyze the total phenolic compounds and antioxidant (ABTS, DDPH, and FRAP) activities. The effects of prepared ground samples were evaluated by feeding them to mice. E. arvense extracts showed strong antioxidant effects. The caffeic acid content was highest in the 70.5% ethanol extract of the vegetative stem, as determined by high-performance liquid chromatography. The blood concentrations of insulin and leptin were significantly lower in mice fed a high-fat diet supplemented with extracts of the root, reproductive stem, and vegetative stem of E. arvense than in mice fed only a high-fat diet. These results suggest that the polyphenolic compounds in E. arvense extracts exert various antioxidant effects. The stems and root of E. arvense can lower the blood levels of insulin and leptin, even after consumption of a high-fat diet.

Introduction
 Materials and Methods
  1. Plant materials and extraction
  2. Preparation of samples for antioxidant analysis
  3. Determination of total phenolic content (TPC)
  4. ABTS radical scavenging assay
  5. DPPH radical scavenging assay
  6. Reducing power assay
  7. Polyphenol compound analysis by HPLC
  8. Animal experiments
  9. Analysis of blood lipids
  10. Statistical analysis
 Results
  1. Total phenolic content (TPC)
  2. ABTS radical scavenging activity
  3. DPPH radical scavenging activity
  4. Reducing power activity
  5. Phenolic contents by HPLC
  6. Animal experiments
 Discussion
 References

• Yong-Hwan Kim(Dept. of Food Science and Biotechnology, Kyonggi University)
• Kyung-Ok Shin(Dept. of Food and Nutrition, Sahmyook University)
• Kyung-Soon Choi(Dept. of Food and Nutrition, Sahmyook University) Corresponding author