Improvement of Lipid Metabolism in Mice Fed a High-Fat Diet Treated with Sudachitin and Development of Sudachi Peel Extract Powder

Abstract

Sudachi, Citrus sudachi, is a major local food in Tokushima Prefecture, and over 98% of this fruit is produced in Tokushima Prefecture. After juice is extracted from sudachi, sudachi peer is not used effectively. Sudachitin, a polymethoxylated flavone is isolated from sudachi peer, and its structure is similar to nobiletin, which possesses anti-inflammatory and anti-obesity actions. First, we evaluated the effect of sudachitin on lipid and energy metabolism in mice fed a high-fat diet. C57BL/6J mice were fed a high-fat diet treated with 5mg/kg/day sudachitin orally for 12 weeks. The mice treated with sudachitin showed significantly decreased body weight gain, body fat and viscera fat compared to that of mice fed a high-fat diet. Moreover, sudachitin improved glucose intolerance and insulin resistance in these mice. We concluded that sudachitin may improve metabolic syndrome by enhancing energy metabolism. Purified sudachitin cannot be used as a food ingredient because of the possibility of side effects and it is too expensive for clinical use at present. Therefore, we tried to produce a sudachi powder which contained sudachitin at high concentration from the dried sudachi peer containing a low amount of sudachitin. It is possible to adjust the content step-by-step from 1% to 80%. We also evaluated the function of sudachi peer extract powder using an animal model of obesity. The mice treated with sudachi peer extract powder showed significantly decreased body weight gain compared to that of mice fed a high-fat diet.