New Zealand spinach (Tetragonia tetragonoides) as a functional food alternative for anti-obesity and anti-hyperuricemia

Obesity is a serious public health problem, associated with the development of metabolic disorders. New Zealand spinach (NZS) growing around the Korean peninsula has been used, but no report is available on its antiobesity effects and mechanisms. Here, we examined the anti-obesity and anti-hyperuricemic effects of NZS and underlying mechanisms in high-fat diet (HFD) obese mice. NZS extract was prepared with 70 % ethanol under reflux in a condensation system at 85◦C for 3 h. Mice were fed the normal fat diet (NFD); high-fat diet (HFD); HFD with 75, 150, or 300 mg / kg NZS extract; or 245 mg / kg Garcinia cambogia (GC) as a reference. Compared to HFD, NZS extracts decreased body weight gain, total white adipose tissue (WAT), and liver weight by the max. 58 %, 64 %, 75 %, respectively, and improved hepatic and plasma lipid profiles, which appeared to be related to the reduced adipogenesis genes including aP2 / FABP4. With NZS, the plasma levels of the leptin and uric acid were significantly decreased while the adiponectin levels were increased. Furthermore, NZS decreased the expression levels of adipogenesis-related genes and xanthine oxidoreductase (XOR), which is involved in uric acid production, while increasing that of proteins associated with fatty acid oxidation. The dose treatment of 300 mg / kg used here would be comparable with about 1500 mg / day in a 60-kg human, which implies that the effect of NZS may be expected for antiobesity. Results indicated that NZS exerts anti-obesity, anti-hyperlipidemia, and anti-hyperuricemic effects by regulation of lipid metabolism-related genes and proteins, and decreased expression of XOR.