Anti-hyperglycemic effect of aqueous extract of Juglans regia L. leaf (walnut leaf) on type 2 diabetic patients: A randomized controlled trial

Abstract Objective The Juglans regia leaf (walnut leaf) has been traditionally used to treat diabetes in Iran. The aim of this study was to evaluate the effect of aqueous extract of Juglans regia leaf on blood glucose in type 2 diabetic patients. Methods Thirty-seven type 2 diabetic patients aged 35–70 years with fasting blood glucose levels between 130mg/dl (7.2mmol/L) and 250mg/dl (13.9mmol/L) and HbA1c more than 7% despite using conventional oral hypoglycemic drugs received the Juglans regia capsule (250mg/TDS) or toast powder capsule (placebo) randomly for 3 months. Fasting blood glucose (FPG), postprandial blood glucose (PPG), and glycosylated hemoglobin (HbA1c) were assessed as primary outcome measures. Lipid profile and hepatic and renal function were assessed as secondary outcome measures. Nonparametric statistical tests were employed to compare the results with baseline in both groups using SPSS version 17. Results Nineteen patients in the Juglans regia group and 18 in the control group with a mean (±SD) age 55.8 (±7) completed the study. The FPG ( p =0.02), PPG ( p =0.008) and HbA1c (p=0.003) levels decreased significantly in the Juglans regia group after 3 months compared to baseline without any side effects. The changes of the variables were not significant in the control group. Conclusions This study suggests that the aqueous extract of J. regia leaf had a lowering effect of FPG, PPG and HbA1c in type 2 diabetic patients. Conducting further clinical studies is suggested with larger sample sizes to make precise conclusions about the efficacy and safety of this herb.