Background: Diabetes mellitus (DM) is a chronic metabolic disorder characterized by persistent hyperglycemia due to insufficient insulin production or the body&rsquo;s inability to effectively use insulin. Neem extract, derived from the leaves of the Azadirachta indica (Neem), is used in various applications, particularly in traditional medicine and as a natural pesticide. This study aims to evaluate the therapeutic effects of neem ethanolic extract on type 1 diabetes mellitus by determining changes in blood glucose levels, serum C-peptide concentrations and peroxynitrite formation in diabetic rats. Specifically, the study seeks to investigate neem&rsquo;s potential to improve glycemic control, preserve endogenous insulin secretion as indicated by C-peptide levels and reduce oxidative and nitrosative stress measured through peroxynitrite levels. 
 
Methods: Ninety Male Rats that were 180-200 g in weight were randomly divided in to six groups 15 rats in each one and kept for approximately seventy days, animal groups: G1: (Negative control). G2: (Positive control) will receive a single STZ dose (50 mg/kg B.W. I/P) to induce diabetes. G3: Will daily receive neem ethanolic extract (500 mg/kg) orally. G4: Diabetic animals will daily receive neem ethanolic extract (400 mg/kg B.W) orally. G5: Diabetic animals will daily receive neem ethanolic extract (500 mg/kg B.W) orally. G6: Diabetic Animals will daily receive Insulin (3 I.U) S/c. 
 
Result: Our results showed that the diabetic group showed an increase in Glucose, Peroxynitrite and a decrease in C-peptide and disruption of the hepatic cords in liver tissue when compared to the control group. When diabetic animals were treated with neem extract and insulin, we observed an improvement in both Peroxynitrite, C-peptide, Glucose and a normal liver structure and a normal distribution of central veins and hepatic cords in liver tissue when compared to the positive group.

Protective Effects of Neem Ethanolic Extract on Streptozotocin-induced Diabetes: Modulation of C-Peptide and Peroxynitrite Levels in Liver Male Rats