Suppressive Effect of Citrus aurantium against Body Fat Accumulation and Its Safety

Abstract

A large number of so-called diet foods containing Citrus aurantium (CA) and its active constituent, synephrine, for suppressing body fat accumulation are currently on the market. However, only one human study has demonstrated the efficacy of CA, and its potential cardiotoxicity has been reported in a rat study. Therefore, we investigated the safety of CA and its suppressive effect against body fat accumulation in rats. High-fat (20% (w/w)) diets containing CA (synephrine content, 6.4%) at 0, 40, 200, 1,000, and 5,000 mg/kg diet were fed to rats ad libitum for 79 days. For dieting, the recommended daily intake of CA in many dietary supplements ranges from 100 to 1,000 mg/day, and the amount used in this experiment was approximately equivalent to 40 and/or 200 mg/kg diet. In the 5,000 mg/kg CA group, the adrenaline and dopamine concentrations in plasma were significantly higher, perirenal fat pad weight was significantly lower, and body weight tended to be lower than in the control group. Although no abnormalities of serum clinical and biochemical parameters were observed except for adrenaline and dopamine, and also no histopathological abnormalities were evident in the heart, heart weight in the 5,000 mg/kg CA group was significantly lower than in the control group. Therefore, it is necessary to examine more precisely the potential cardiotoxicity caused by excess intake of CA. Particularly, the elucidation of influences of the simultaneous intake of CA and some stimulants, such as caffeine, awaits further characterization.