Boysenberry polyphenols suppressed elevation of plasma triglyceride levels in rats

Abstract

Boysenberry, a hybrid Rubus berry, is mainly cultivated in New Zealand. We previously reported that consumption of boysenberry juice (BBJ) exhibited anti-obesity effects in high-fat feeding rats. In this study, we focused on the suppressive effect of BBJ and its fraction on triglyceride absorption from the gastrointestinal tract. BBJ effectively inhibited pancreatic lipase activity in vitro, and was separated into four fractions (Fr1, Fr2, Fr3 and Fr4) by HP-20 column chromatography. Among all the fractions, Fr3, the ellagic acid-rich fraction, showed the most potent inhibition against pancreatic lipase in vitro with Fr2, the anthocyanin-rich fraction, second. Authentic ellagic acid equivalent in Fr3 showed poor activity against pancreatic lipase. Then, each fraction was orally administered with corn oil to rats fitted with a jugular catheter to examine the effects of each fraction on plasma triglyceride levels. Both Fr2 and Fr3 effectively suppressed the plasma triglyceride level elevation at a dose of 1,000 mg/kg body weight. These findings demonstrated that BBJ contains chemical components which inhibit triglyceride absorption from the gastrointestinal tract.