Hypoglycemic and hypolipidemic effects of fermented milks with added roselle (Hibiscus sabdariffa L.) extract

The present study was aimed to evaluate the physicochemical properties of fermented milk containing roselle (Hibiscus sabdariffa L.) extract at different levels (0, 0.1, 0.2 and 0.3% (w/w)). Titratable acidity (TA) and pH, bacteria counts, syneresis value, water-holding capacity (WHC) and their sensory acceptance were evaluated afterwards. The fermented milk containing 0.2% roselle extract (RFM2) was selected for investigation of hypoglycemic and hypolipidemic activity. Results showed that RFM2 decreased the fasting blood glucose (FBG) levels, glycosylated hemoglobin A1c (HbA1c), the level of liver glycogen, and increased serum insulin (INS) of diabetic model mice. Moreover, RFM2 treatment improved the body, spleen, pancreas, liver and kidney weights of diabetic mice to different degrees. After four weeks, TC concentrations in diabetic mice treated by metformin (DM), control fermented milk (CFM) and RFM2 (RFM) group was decreased by 52.52%, 43.56%, 49.10%, respectively, compare to diabetic control (DC) group, TG concentration was decreased by 52.61%, 26.49%, 33.96%, respectively. LDL-C concentration was decreased by 63.97%, 46.32%, 55.88%, respectively. And the level of HDL-C in DM, CFM, RFM group was increased by 49.12%, 37.72%, 42.11%, respectively. The FFA levels of DM, CFM and RFM group was decreased by 60.05%, 19.94%, 34.08%, respectively, compared to DC group. After diabetic mice fed with metformin, CFM and RFM2, compared with DC group, the expression of adenosine monophosphate-activated protein kinase (AMPK) in the liver was increased by 50.29%, 16.93%, 41.69%, while the expression of glucose-6-phosphatase (G6P) was downregulated which decreased by 15.42%, 6.47%, 12.44%, respectively. The expression of AMPK and glucose transporter 4 (Glut4) in skeletal muscle was increased in DM, CFM and RFM groups, which was increased by 70.86%, 28.64%, 51.73% and 58.42%, 45.18%, 48.07%, respectively. The expression of peroxysome proliferator-activated receptor (PPAR-γ) in adipose tissue was increased by 5.80%, 12.63%, 28.67%, respectively. In general, roselle extract addition could promote hypoglycemic and hypolipidemic effects of fermented milk.