Antidiabetic and Antioxidative Potential of the Blue Congo Variety of Purple Potato Extract in Streptozotocin-Induced Diabetic Rats

Abstract

This study was designed to evaluate the effects of purple potato extract of the Blue Congo variety (PP) on diabetes and its antioxidant activities after two-week administration tostreptozotocin (STZ)-induced diabetic rats. The activities of PP were evaluated at a dose of 165 mg/kg body weight (b.w.) by estimating biochemical changes in blood plasma and through a histopathological study of kidney, muscles, and liver tissue. We evaluated the effect of treatment with extract on glucose level, glycated hemoglobin, activities of enzymatic antioxidants (including superoxide dismutase, glutathione peroxidase, and catalase), and lipid peroxidation. Moreover, we determined advanced glycation end-products (AGEs), advanced oxidation protein products (AOPPs), and the level of oxidative modified proteins (OMPs) as markers of carbonyl-oxidative stress in rats with diabetes. Using high-performance liquid chromatography, we identified five anthocyanins and six phenolic acids in the extract from Blue Congo with the dominant acylated anthocyanin as petunidin-3-p-coumaroyl-rutinoside-5-glucoside. The administration of Blue Congo extract lowered blood glucose, improved glucose tolerance, and decreased the amount of glycated hemoglobin. Furthermore, PP demonstrated an antioxidative effect, suppressed malondialdehyde levels, and restored antioxidant enzyme activities in diabetic rats. After administration of PP, we also noticed inhibition of OMP, AGE, and AOPP formation in the rats′ blood plasma.

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“…Intraperitoneal injection of STZ had a necrotic effect on insulin-producing pancreatic β-cells leading to hyperglycemia and a significant decrease in insulin secretion within 48 h after injection. 53 In our study, there was a significant elevation in blood glucose in the study group compared to the control group. The same thing happened in the study group before and after injection of STZ in accordance with El-Baz et al, 54 who found that animals injected with STZ exhibited a significant elevation in glucose blood levels after 30 days by 2.7-folds, when compared to normal animals.…”

Dunaliella salina Attenuates Diabetic Neuropathy Induced by STZ in Rats: Involvement of Thioredoxin

“…BioMed Research International 7 histopathological study. Several investigations showed that STZ enters the pancreatic β-cells by glucose protein-2 transporter and disrupts the balance between antioxidant and oxidant systems damaging the insulin-producing islet β-cells and inducing the progression of diabetes [23,24]. Another study showed STZ produced islet β-cells injury, which in turn elevated glucose level and decreased insulin level [25].…”

Loganic Acid, an Iridoid Glycoside Extracted from Cornus mas L. Fruits, Reduces of Carbonyl/Oxidative Stress Biomarkers in Plasma and Restores Antioxidant Balance in Leukocytes of Rats with Streptozotocin-Induced Diabetes Mellitus

“…The degradation product of LPO, malondialdehyde (MDA), reacts with TBA at 100° C to form colored complex. The level of MDA was expressed as nmol/mL of plasma or as pmol/million of leukocytes using 156,000 M −1 cm −1 as a molar absorption coefficient at λ = 532 nm [ 20 , 21 ].…”

“…The level of OMPs was determined following the method described by Demkovych et al [ 22 ] with a slight modification [ 20 ]. The method is based on spectrophotometric detection of hydrazones formed in the reaction of aldehyde and ketone groups of aliphatic amino acid residues with the 2,4-dinitrophenylhydrazine that absorb at λ = 370 nm (OMP 370 nm —OMPs of neutral characteristics) and at λ = 430 nm (OMP 430 nm —OMPs of basic characteristics).…”