Antidiabetic and antioxidant effects of saponarin from Gypsophila trichotoma on streptozotocin-induced diabetic normotensive and hypertensive rats

Background: Diabetes and hypertension are diseases that often coexist, which increases the risk of chronic organ damages and cardiovascular complications.

Purpose: To evaluate the effects of saponarin, isolated from Gypsophila trichotoma Wend, on blood pressure, glycemia, body weight, and liver biochemical parameters related to oxidative stress in diabetic normotensive Wistar Kyoto rats (NTR) and spontaneously hypertensive rats (SHR).

Methods: Diabetes was induced by administration of streptozotocin (40 mg/kg, i.p.). The following biochemical parameters: reduced glutathione (GSH), malondialdehyde (MDA), total Cytochrome P450, aniline hydroxylase (AH) activity, as well as the activities of antioxidant enzymes such as Glutathione Peroxidase (GPx), glutathione reductase (GR) and glutathione S-transferase (GST) were measured in the livers of euthanized rats.

Results: Saponarin exerted slight antihypertensive activity in non-diabetic SHR, judged by 19% (p<0.05) decrease of the initial blood pressure. However, such effect was not observed in streptozotocin-induced diabetic SHR (SHR-D). Streptozotocin-induced diabetes was evidenced by 78% (p<0.05) and by 171% (p<0.05) increase in blood glucose level in NTR and SHR, respectively. In non-diabetic SHR the initial MDA quantity was by 36% (p<0.05) higher and the initial GSH levels were by 28% (p<0.05) lower in comparison to non-diabetic NTR. Significant decrease in the activities of GPx, GR, and GST was measured in the livers of all diabetic rats. Treatment with saponarin ameliorated the above mentioned liver parameters in both diabetic strains, however its effects were less pronounced in the diabetic SHR group.

Conclusion: Taken together our data indicate that diabetes and hypertension in combination are more difficult to be modulated by saponarin.