Dietary anthocyanin-rich Haskap phytochemicals inhibit postprandial hyperlipidemia and hyperglycemia in rats

Haskap (Lonicera caerulea L.) fruit contains some bioactive phenolic phytochemicals, mainly cyanidin-3-glucoside (cy3-glc) and chlorogenic acid. The purpose of this study was to investigate the effects of anthocyanin-rich phenolic phytochemical (containing 13.2% anthocyanin) purified from a Haskap fruit (named Haskap phytochemical) on postprandial serum triglyceride and blood glucose levels. The Haskap phytochemical (containing cy 3-glc at 300 mg/kg of body weight) was administered orally to rats fasted for 24 h and 30 min later, a corn oil emulsion was administered to these rats. After the administration, serum triglyceride concentration was measured. An increase in serum triglyceride concentration and the AUC significantly lowered in the Haskap phytochemical-administered group than in the saline-administered group. To evaluate the effect of serum glucose levels, the Haskap phytochemical was orally administered to rats fasted for 24 h and sucrose solution (2 g/kg of body weight) was administered to these rats after 30 min. After the administration, blood glucose level was measured. The Haskap phytochemical significantly reduced the increase in blood glucose levels and AUC in the Haskap phytochemical-administered group than in the saline-administered group. Furthermore, to investigate the long-term effects of Haskap phytochemical intake, high-fat diet (HF diet) with 1.5% or 3.0% Haskap phytochemical was administered to rats for four weeks. The investigation of chronological changes in the serum components of the rats fed HF diets in addition to the administration of Haskap phytochemical showed that the increase in serum triglyceride concentrations, total cholesterol concentrations and blood glucose were significantly suppressed compared to the HF diet-fed control (HF-control). These results suggest that the decrease in postprandial blood lipids and blood glucose by short or long-term Haskap phytochemical ingestion is due to anthocyanin and other polyphenols contained in the Haskap phytochemical.