Objectives: The effects of morroniside isolated from Corni Fructus on renal lipids and inflammation provoked by hyperglycaemia were investigated using type 2 diabetic mice.
Methods: Morroniside was administered orally to db/db mice at 20 or 100 mg/kg daily for 8 weeks, and its effects were compared with those in vehicle-treated db/db and m/m (non-diabetic) mice. Serum and renal biochemical factors and protein expression related to lipid homeostasis and inflammation were measured.
Key findings: Morroniside produced significant dose-dependent reductions in serum triglyceride and renal glucose and lipid levels. Morroniside altered the abnormal protein expression of sterol regulatory element binding proteins (SREBP-1 and SREBP-2). In addition, the formation of reactive oxygen species and lipid peroxidation were inhibited in the morroniside-treated db/db mouse group, and the ratio of reduced glutathione to the oxidised form was significantly elevated. These results suggest that morroniside alleviated oxidative stress in the kidneys of db/db mice. Furthermore, 100 mg/kg morroniside down-regulated the expression of nuclear factor-kappaBp65, cyclooxygenase-2 and inducible nitric oxide synthase augmented in db/db mice.
Conclusions: Morroniside may inhibit abnormal lipid metabolism and inflammation due to reactive oxygen species in the kidneys in type 2 diabetes.