The efficacy of Prosopis glandulosa as antidiabetic treatment in rat models of diabetes and insulin resistance

Ethnopharmacological relevance: Diabetes mellitus is rampantly increasing and the need for therapeutics is crucial. In recognition of this, untested antidiabetic agents are flooding the market. Diavite (TM) which is a product consisting solely of the dried and ground pods of Prosopis glandulosa (Torr.) [Fabaceae] is currently marketed as a food supplement with glucose stabilizing properties. However, these are anecdotal claims lacking scientific evidence. The aim of this study was to determine the efficacy of Prosopis glandulosa as an antidiabetic agent. Materials and methods: Male Wistar rats were rendered (a) type 1 diabetic after an intraperitoneal injection of STZ (40 mg/kg) and (b) insulin resistant after a 16-week high caloric diet (DIO). Zucker fa/fa ZDF rats were used in a pilot study. Half of each group of animals was placed on Prosopis glandulosa treatment (100 mg/kg/day) for 8 weeks and the remaining animals served as age-matched controls. At the time of sacrifice, blood was collected for glucose and insulin level determination, the pancreata of the STZ rats were harvested for histological analysis and cardiomyocytes prepared from the DIO and Zucker fa/fa hearts for determination of insulin sensitivity. Results: Type 1 diabetic model: Prosopis glandulosa treatment resulted in significant increased insulin levels (p < 0.001), which was accompanied by a significant decrease in blood glucose levels (p < 0.05). Additionally, Prosopis glandulosa treatment resulted in increased small beta-cells (p < 0.001) in the pancreata. The body weight of the STZ animals decreased significantly after STZ injection, with Prosopis glandulosa treatment partially preventing this. Zucker fa/fa rats: Prosopis glandulosa treatment significantly reduced fasting glucose levels (p < 0.01) and improved IPGTT, when comparing treated to untreated animals. DIO insulin resistant model: Prosopis glandulosa treatment resulted in an increased basal (p < 0.01)and insulin-stimulated (p < 0.05) glucose uptake by cardiomyocytes prepared from this group. Conclusions: The present study showed that Prosopis glandulosa treatment moderately lowers glucose levels in different animal models of diabetes, stimulates insulin secretion, leads to the formation of small beta-cells and improves insulin sensitivity of isolated cardiomyocytes. (C) 2011 Elsevier Ireland Ltd. All rights reserved.