Biology., 2021., 10(1), 43;

Flaxseed Lignans and Polyphenols Enhanced Activity in Streptozotocin-Induced Diabetic Rats

Draganescu, D Andritoiu, C Hritcu, D et al.


Flaxseeds play an important role in human health due to their chemical composition and recognized beneficial outcomes. This study investigated the antidiabetic effects of present lignans and polyphenols found in the flaxseed extract on streptozotocin (STZ)-induced diabetic rats. The flaxseed administration produced favorable changes in body weight, food and water intake, and glycosylated hemoglobin and blood glucose quantities in the treated diabetic rats. Additionally, significant positive results were observed in the biochemical parameters, namely reduced plasma cholesterol, LDL cholesterol and triglycerides, plasma creatinine, and urea and uric acid levels, highlighting the seeds’ use in traditional medicine. The results were sustained by histopathological observations that showed better tissue preservation following the flaxseed diet. Overall, the consumption of flaxseeds produced moderate reduction in glucose levels and hyperlipidemia, together with improvement in the impaired organs’ function in diabetic rats. The daily administration of polyphenols and lignans compounds could impact therapeutic potential in diabetes management.

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Key points

Diabetes mellitus is a metabolic condition that affects millions of people globally. The present study highlights the enhanced activity of flaxseed lignans and polyphenols isolated from Linum usitatissimum in streptozotocin (STZ)-induced diabetic rats. Treatment with flaxseed extract showed enhanced glycosylated hemoglobin and blood glucose levels and reduced plasma cholesterol, low-density lipoprotein (LDL) cholesterol and triglycerides, urea and uric acid intensities, and plasma creatinine in the treated diabetic experimental animals, indicating beneficial effects—results sustained by histopathological observations of liver, pancreas, kidney, and spleen. Translation of this nutraceutical-based approach still requires further elucidation of its mechanism of action toward clinical applications. The literature data suggest that flaxseed consumption may protect against this metabolic syndrome by decreasing glucose and lipid concentrations, by postponing postprandial glucose absorption, and by reducing inflammation and oxidative stress. Recent studies prove that SDG, due to its known antioxidant activity and its capacity to defeat the gene expression in primary hepatocyte cell cultures, is able to inhibit the DM development in Zucker rat animal models. Studies highlight the antidiabetogenic activity of Linum usitassimum fraction (LU6) in single dose STZ-induced diabetic Swiss mice. Daily administration of LU6 indicated beneficial effects in reducing postprandial hyperglycemia, endogenous insulin secretion, and islet regeneration, which can decrease the risk of developing type II diabetes in patients with impaired glucose tolerance.

Overall, the presented results display that flaxseed extract can serve as a promising additional therapy approach in managing diabetes due the quantified effects: reduced blood glucose levels, body weight loss, and food and water intake and improved lipid and renal profile. Additionally, the histopathological investigations showed that flaxseed extract partially recovers pancreas, liver, and kidney functions, thus reducing the lesions associated with the diabetic state. Therefore, the administration was successful in reducing blood glucose, lipid profiles, and histopathology of pancreatic β-cells, although it did not bring them to normal levels after 60 days. The potential way that the values could be brought closer to normal could be either by dose–response studies and multiple markers measurement (proteinuria, insulin sensitivity, or urinary excretion of glucose) or by multiple STZ low-dose administration for fewer toxic effects and therefore an enhanced effect of flaxseed extract. The present study creates further opportunities to separate the active constituents from flaxseed that are accountable for antidiabetic activity and to clarify their mechanism of action. More studies are required that drive together primary preclinical and clinical results with standardized product formulations development to optimize the dose of polyphenols and lignans within an edible product that could be administered along with classic therapy.