Impact of Mulberry Leaf Extract and Mulberry Leaf Powder on Serum Nesfatin-1 Level in Nicotinamide/Streptozotocin-Induced Type 2 Diabetic Rats

In traditional medicine, leaves of white mulberry (Morus alba L.) are used as antidiabetic agents. Considering the presence of flavonoids, this plant exhibits insulin mimetic activities. Nesfatin-1 is described as an anorexigenic regulatory peptide, which can influence glucose metabolism via insulin sensitivity enhancement. This study examined the effects of both mulberry leaf powder and extract (MLP and MLE) on fasting blood glucose (FBG), nesfatin-1, and insulin in diabetic Wistar rats.

Five groups of rats (n, 40) were included and examined in this study. A group was selected as the healthy control (I), while the other groups received streptozotocin and nicotinamide (55 and 110 mg/kg bw, respectively) for diabetes induction. Diabetic rats were then grouped as follows: control group (II); sham group (receiving ethanol) (III); treatment group receiving 600 mg/kg/day of MLE (IV); and treatment group receiving 25% MLP (V). After 6 weeks, we measured insulin, nesfatin-1, and FBG in the groups. 

The FBG level decreased in the treatment groups, while serum insulin increased in comparison with the diabetic controls. In addition, serum level of nesfatin-1 improved significantly (to an almost normal level) in MLP rats in comparison with the diabetic controls. (pvalue<0.05) The effects of MLE on serum nesfatin-1 was similar to MLP but not significant. (pvalue>0.05)

Considering the reduction in insulin level and the rise in blood glucose, the diabetic control group showed an increase in serum nesfatin-1 with a compensatory mechanism, while hyperglycemia improved in the MLE and MLP groups, and the level of nesfatin-1 reduced. MLP showed greater efficacy than MLE in the improvement of nesfatin-1, which might be related to the presence of ethanol in MLE.