Anthocyanins in purple corn may help diabetics

Bioactive compounds found in the pigment of purple corn are showing potential to prevent or improve complications related to type 2 diabetes. A study from researchers at the University of Illinois (U of I) published in Plos One reports that anthocyanins in the pigment in purple corn activated novel biological markers related to enhanced insulin secretion and glucose uptake. When activated, these markers can improve health complications caused by type 2 diabetes.

“There is a huge concern about the number of people dying from consequences of type 2 diabetes,” explained Elvira de Mejia, professor in the Dept. of Food Science and Human Nutrition at U of I, and co-author of the study. “We have been studying several bioactive compounds, trying to understand the mechanism of action and how the diet can decrease or prevent a pre-diabetic situation developing into a diabetic physiological problem.”

Diego A. Luna-Vital, a post-doctoral researcher in de Mejia’s lab, said that they looked at two novel biomarkers to determine if the anthocyanins would influence them. These included the free fatty acid receptor (FFAR1) and glucokinase. “This free fatty acid receptor is located mainly in pancreatic cells and interacts with the fat—the free fatty acids that are circulating in our blood after a meal. The activation of this receptor (FFAR1) concludes in the secretion of insulin. This is the importance of this receptor. If we activate it, it can act as an alternative to secrete insulin in people who are diabetic and cannot utilize glucose as a sensor for secreting insulin on their own,” Luna-Vital explained.

The enzyme glucokinase is the master regulator of glucose and carbohydrate metabolism in the liver. “So to reduce blood sugar levels, we need to promote the activation of this enzyme, which will, in turn, promote glucose uptake. And if that happens, there is less sugar circulating in the blood,” he added. The researchers found that the phenolics present in the pigment activated both FFAR1 and glucokinase.

In a liver cell culture, they also observed an activation of the glucokinase. “Compared to a physiological state after a meal, this extract can increase the activation of glucose metabolism and glucose uptake by the liver cells,” Luna-Vital noted.

This effect has been further confirmed in an ongoing in vivo study where mice fed a high-fat diet had lower blood glucose levels when they were given the colored corn pericarp extract, compared to the mice with no extract. The mechanisms of action are still under investigation.

Study