Insulin response in peripheral tissues in animals chronically treated with aqueous extract of Hibiscus sabdariffa L.

Materials and methods Male Wistar rats were primary divided into two groups: Control (C) received standard chow and water ad libitum; Fructose (F) received standard chow and water containing 7% of fructose ad libitum. At 90 days of age they were one more time re-divided into 4 groups: Control treated with water (C, n=7); Control treated with HS (CHib, n=6); Fructose treated with water (F, n=8); Fructose treated with HS (FHib, n=9). Treatment with HS was daily for 4 weeks at a dose of 800 mg/kg. After treatment period, all rats were submitted to insulin tolerance tests (ITT) with two types of insulin (intermediary and short acting) in order to assess the peripheral tissues in response the action of insulin. Data obtained was estimated glucose uptake index (GUI). All data statistically analyzed with 5% significance. Results TTI performed with insulin NPH (intermediary) show that only C group decreased glycaemia at timepoint 15′ compared to fasting glycemia (0′). The analyses between groups shows that CHib animals increased at timepoint 15′ and F group decreased at fasting and 5′ timepoints. The GUI data showed the F group had lowered the glucose uptake capacity compared to C group. The TTI performed with insulin Lispro (short acting) showed that CHib group decreased glucose concentration at timepoint 15′. On the other hand, F and FHib groups decreased in 10′ and 15′ compared to its fasting glycemia. Evaluations between groups shows the CHib rats lowered the serum glucose at 15′, F rats decreased at timepoints 5′, ‘10’ and 15′ and finally the FHib rats decreased this biomarker at 10′ and 15′. GUI data for Lispo ITT shows the fructose treatment improved the glucose uptake when compared to control rats