Hepatic mechanisms of the Walnut antidiabetic effect in mice

Abstract

The present study was designed to explore the mechanism of action of walnut (the seed of Juglans regia) leaf and ridge on hepatic glucose metabolism in diabetic mice. Experimental diabetes was induced by intravenous administration of streptozotocin (60 mg/kg) and confirmed with an increase of blood glucose, 90-100% of the control, 72 hours later. Isolated extracts from walnut leaf and ridges were administered in a single effective dose of 400 mg/kg orally. Firstly, blood glucose was determined every 1 hour until 5 hours post administration of extracts. In the second experiment, the liver was surgically removed, 2 hours post treatment of diabetic animals with extracts, homogenized and used for measurement of key enzymes of glycogenolysis (glycogen phosphorylase, GP) and gluconeogenesis (phosphoenolpyruvate carboxykinase, PEPCK). Treatment by both leaf and ridge extracts decreased blood glucose and liver PEPCK activity and increased blood insulin and liver GP activity. It is concluded that walnut is able to lower blood glucose through inhibition of hepatic gluconeogenesis and secretion of pancreatic insulin.© Versita Sp. z o.o.

Effects of a hydroalcoholic extract of Juglans regia (walnut) leaves on blood glucose and major cardiovascular risk factors in type 2 diabetic patients: a double-blind, placebo-controlled clinical trial

“…This finding may be indicative of regeneration of the beta cells [ 9 ]. According to the study by Kamyab et al [ 21 ] in mice, oral walnut leaf and ridge extracts significantly reduced liver pyruvate carboxykinase activity and increased liver glycogen phosphorylase activity. They concluded that walnut could reduce the blood glucose level by inhibiting hepatic gluconeogenesis and stimulating secretion of pancreatic insulin.…”

Pancreatic beta cell protection/regeneration with phytotherapy

“…Its leaves have shown a significant hypoglycemic effect in diabetic animals. Increase of hepatic glycogenolysis, decrease of gluconeogenesis, inhibition of glucose absorption from the intestine, and enhancing serum insulin are the proposed mechanisms for hypoglycemic effect of J. regia (Asgary et al, 2008;Kamyab et al, 2010;Jelodar, Mohsen, Shahram, 2007). Increase of insulin level can be mediated through regenerative actions of J. regia on pancreatic islets.…”

“…Numerous experimental and clinical studies have documented beneficial effects of phytotherapy for managing diabetes (Ghorbani, 2013a,b). Antidiabetic effect of phytochemicals is mediated through different mechanisms such as decreasing glucose absorption from intestine, inhibiting glucose production in the liver, increasing glucose uptake by tissues, enhancing insulin secretion from beta cells, and/or increasing pancreatic tissue regeneration (Asgary et al, 2008;Kamyab et al, 2010;Jelodar, Mohsen, Shahram, 2007;Shafiee-Nick et al, 2011;Shafiee-Nick et al, 2012a). The current review focused on phytochemicals, the antidiabetic action of which has been proved, at least in part, by pancreatic beta cell protection or regeneration (Table I).…”

Pancreatic Protective and Therapeutic Effect of Arachis Hypogaea Skin Extracts Against Carbon Tetrachloride (Ccl4) in Mice

“…Numerous experimental and clinical studies have documented beneficial effects of phytotherapy for managing diabetes 7 . Antidiabetic effect of phytochemicals is mediated through different mechanisms such as decreasing glucose absorption from intestine, inhibiting glucose production in the liver, increasing glucose uptake by tissues, enhancing insulin secretion from beta cells, and/or increasing pancreatic tissue regeneration [28][29][30] .…”