Effect of Birhi Vaiety of Date Palm Fruits, (Phoenix dactylifera L.) at the Tamr Stage on Serum Glucose Levels in Streptozotocin-Induced Diabetic Rats

This study was carried out to investigate the effect of a dietary preparation of Birhi tamr (Phoenix dactylifera L.) on serum glucose levels and body weight in normal, diabetic insulin-treated and diabetic insulin-untreated rats. Diabetes was partially induced by intraperitoneal injection of streptozotocin (32.25 mg/kg). Thirty six male Sprague-Dawley rats (239 ± 8.4 g) were divided into two normal, two diabetic insulin-treated and two diabetic insulin-untreated groups. Each group was fed a diet containing either 0% or 10% tamr for six weeks. Fasting serum glucose levels were determined by enzymatic-calorimetric method using a standard kit procedure.Feeding 10% tamr did not show significant differences (P > 0.05) in serum glucose levels in any of the normal and insulin-treated diabetic rats. Insulin-untreated diabetic rats fed 0% tamr or 10% tamr exhibited significantly (P < 0.05) higher serum glucose levels (496 ± 81.6, 315 ± 61.1 mg/dl respectively) compared to normal (147 ± 5.3, 156 ± 7.6 mg/dl respectively) and insulin-treated diabetic rats (227 ± 17.6, 268± 18.9 mg/dl respectively). Feeding 10% tamr to insulin-untreated rats induced significant (P < 0.05) reduction in this variable. The findings of the present study may provide support for the favourable effect of date palm fruits as tamr, on blood glucose in streptozotocin-diabetic rats. This effect cannot be simply explained on the basis of the macro-nutrient composition of tamr. However, due to the apparent effects of tamr on blood glucose in normal and insulin-treated and insulin-untreated diabetic rats, the possible presence of insulin-like substance in tamr may not be excluded. The mechanism of action of the blood glucose-lowering effect of tamr awaits further investigation.