Naringenin and hesperetin, two flavonoids derived from Citrus aurantium up-regulate transcription of adiponectin.

The dried, immature fruit of Citrus aurantium L., 'Zhiqiao' in Chinese, has been used to treat cardiovascular diseases in traditional Chinese medicine for centuries. Naringenin and hesperetin and their glycosides present in considerable amounts (about 10 approximately 15%) in the herb. The aim of this study is to test whether naringenin and hesperetin influence adiponectin expression, which plays an important role in glucose and lipid metabolism with antiatherogenic and anti-inflammatory properties. Treatment with naringenin and hesperetin enhanced adiponectin transcription in differentiated 3T3-L1 cells. Both naringenin and hesperetin induced peroxisome proliferator-activated receptor (PPAR)gamma-controlled luciferase expression in a dose-dependent manner (20-160 microM), whereas only naringenin possessed significant activity to activate PPARalpha. These results suggested the two flavonoids might exert antiatherogenic effects partly through activating PPAR and up-regulating adiponectin expression in adipocytes. Our findings give new insight for the molecular explanations for the therapeutic effects of Zhiqiao. (c) 2008 John Wiley & Sons, Ltd.