Effect of hesperetin, a citrus flavonoid, on the liver triacylglycerol content and phosphatidate phosphohydrolase activity in orotic acid-fed rats

The effect of dietary hesperetin on the hepatic lipid content and the enzym e activities involved in triacylglycerol (TG) synthesis in rats fed diets w ith or without 1% orotic acid (OA) was studied. Hepatic TG content was rais ed by approximately 5-fold after administration of OA for 10 days. The OA-f eeding significantly increased the activity of hepatic microsomal phosphati date phosphohydrolase (PAP), which is the rate-limiting enzyme for TG synth esis. Hepatic glucose-6-phosphate dehydrogenase (G6PDH) and malic enzyme ac tivities were also increased. An addition of 1% hesperetin to the OA-supple mented diet resulted in the decrease of the hepatic TG content by 44% and o f microsomal PAP activity. Dietary hesperetin alone neither affected liver TG content nor PAP activity significantly. OA-feeding caused an increased l iver cholesterol level, whereas simultaneous addition of hesperetin and OA reduced its content to the control level. A slight reduction of hepatic cho lesterol by hesperetin was also observed in the OA-free dietary group. The present study demonstrated that dietary hesperetin can reduce the hepatic T G accumulation induced by OA, and this was associated with the reduced acti vity of TG synthetic enzyme, PAP.