The effect of oral carob extract on blood proinflammatory cytokines, oxidant/antioxidant balance and some biochemical parameter levels in a streptozotocin-nicotinamide induced diabetic rat model.

The development and complications of diabetes constitute an important health problem. Herbal treatments have the potential to benefit against the pathogenesis of diabetes. For this reason, the effect of carob fruit on the pathogenesis of diabetes and diabetic status, which it has been reported by recent studies that it may have an important health potential, should be evaluated more clearly. In the study, 200–250 g male Wistar albino rats were divided into four groups of 10 rats each. Aqueous extract of carob fruit (pulp and seed) prepared by ultrasonic-assisted extraction method was administered by gastric gavage at a dose of 200 mg/kg for 21 days to the carob group (C) consisting of healthy rats and the diabetes+carob group (D+C) consisting of streptozotocin-nicotinamide (STZ-NA)-induced rats. The other groups consisted of the Control group (Control) consisting of healthy rats and the diabetes group (D) consisting of STZ-NA-induced rats which were given physiological saline by gastric gavage for 21 days. At the end of the experiment, blood samples were collected from the animals in heparinized plasma and K2 EDTA hemogram tubes. Glucose, insulin, HOMA-IR, leptin, total cholesterol, TG, 25-hydroxy vitamin D, MDA, GSH, IL-1β, TNF-α, IL-6, ALT, AST, creatinine and BUN values were determined from plasma samples. HbA1c and complete blood count were measured from hemogram tubes. Fasting blood glucose, HbA1c, HOMA-IR levels of STZ-NA-induced diabetic rats were significantly increased compared to the rats in the groups of healthy animals, while the carob aqueous extract application did not affect these values positively (p>0,05). Insulin levels did not show any difference between the groups. While no significant difference was observed between the groups in leptin levels, a significant positive correlation was observed between leptin and IL-6 levels in the D+C group. TG, MDA, IL-6, ALT and BUN levels significantly increased in the diabetic groups compared to the healthy groups, but the carob aqueous extract application had no positive effect on these levels. 25-hydroxy vitamin D levels significantly decreased in the D+C group compared to the C and Control groups. GSH levels significantly increased in the D+C group compared to the other groups. In addition, a significant positive correlation was observed between GSH levels and erythrocyte count in the D+C group. There was no significant effect of the treatments on IL-1β levels. Total cholesterol, TNF-α, AST and creatinine levels were not significantly different between the groups. In complete blood count parameters, eosinophil count and percentage significantly decreased in the diabetic groups compared to the healthy groups. Erythrocyte count decreased significantly in the D+C group compared to the other groups, Hb levels decreased significantly in the D+C group compared to the Control and D groups, and decreased significantly in the C group compared to the Control group. Hct levels decreased significantly in the D+C group compared to the Control and D groups. A significant positive correlation was observed between erythrocyte count and Hb and Hct in the D+C group. MCV significantly increased in the D+C group compared to the other groups. RDW-SD significantly increased in the D+C group compared to the groups with healthy animals, while it significantly increased in the D group compared to the Control group. A significant positive correlation was observed between MCV and RDW-SD in the D+C group. Platelet count significantly decreased in the diabetic groups compared to the healthy groups. PCT decreased significantly in the D+C group compared to the Control and C groups, and decreased significantly in the D group compared to the Control group. The weights of animals in each group did not differ between the beginning and end of the experiment. It was observed that the weight changes of the animals between the beginning and the end of the experiment did not differ between the groups. In conclusion, in this study it was observed that the application of carob aqueous extract had no positive effect on the glucose levels of diabetic animals, and that it did not alleviate oxidative stress, systemic inflammation and lipid levels.