Satsuma mandarin (Citrus Unshiu MARC.), which is a widely consumed citrus fruit in Japan, contains flavanone glycosides such as hesperidin and narirutin. Flavanone glycoside contents were higher in discarded unripe Satsuma mandarin (USM) than in edible ripe ones. Sprague-Dawley rats were fed diets containing USM at the levels of 2.5, 5.0 or 10.0% for 4 weeks. USM feeding at 2.5 or 5.0% did not affect serum and hepatic lipid levels. USM intake at the level of 10.0% significantly lowered serum concentrations of triglycerides, free fatty acids, glucose, insulin, and leptin compared with the USM-free (control) diet. Hepatic triglyceride and cholesterol levels were also significantly lowered. In addition, hepatic enzyme activities related to lipogenesis, but not lipolysis, were significantly lowered. Fat excretion into feces was not affected by UMS feeding. These results suggested that feeding of discarded USM rich in flavanone glycosides showed hypolipidemic, especially hypotriglyceridemic effects, partly through the suppression of hepatic lipogenesis.
