Comparative effects of Citrullus colocynthis, sunflower and olive oil-enriched diet in streptozotocin-induced diabetes in rats.

Citrullus colocynthis (colocynth) seeds are traditionally used as antidiabetic medication in Mediterranean countries. The present study evaluated the differential effects of diets enriched with C. colocynthis, sunflower or olive oils on the pancreatic beta-cell mass in streptozotocin (STZ)-induced diabetes in rats. STZ injection induced rapid hyperglycaemia in all animals. However, 2 months later, hyperglycaemia was significantly less pronounced in the rats fed a C. colocynthis oil-enriched diet compared with other rat groups (7.9mM versus 12mM and 16mM with colocynth versus olive and sunflower oils, respectively). Assessment of insulin sensitivity using the homoeostasis model assessment (HOMA) method also indicated less insulin resistance in the rats fed a C. colocynthis oil-enriched diet versus the other rats. Finally, 2 months after STZ injection, the pancreatic beta-cell mass was similar in both the STZ-treated rats fed the colocynth oil-enriched diet and their controls fed the same diet. In contrast, the pancreatic beta-cell mass remained lower in the STZ-induced diabetic rats fed with olive oil- and sunflower oil-enriched diets compared with the C. colocynthis group. We conclude that C. colocynthis oil supplementation may have a beneficial effect by partly preserving or restoring pancreatic beta-cell mass in the STZ-induced diabetes rat model.