Purple corn is grown in Peru and Chile and is rich in anthocyanins (also known as flavonoids), which are believed to have anti-diabetic properties. A Korean study investigated the cellular and molecular activity of purple corn anthocyanins (PCA) on the development of diabetic nephropathy.
The two-part study, published in the American Journal of Physiology – Renal Physiology, examined the effects of PCA on human cells in vitro and the effects of PCA on kidney tissue in mice with diabetes.
In the in vivo experiment, diabetic and control mice were dosed with PCA for eight weeks, then changes in kidney tissue were assessed and immunohistological analyses were performed. Kidney tissue was further analyzed for levels of inflammatory chemokines, which are key components in diabetic nephropathy.
Researchers found that in human endothelial cells cultured in hyperglycemic kidney conditions, induction of endothelial cell adhesion molecules decreased in a dose-dependent manner with PCA exposure, meaning that the PCA likely interfered with cell-cell adhesion in glomeruli.
In mice with diabetes, PCA exposure slowed mesangial expansion and interrupted the cellular signaling pathway that may instigate glomerular adhesion and infiltration of inflammatory cells responsible for diabetic glomerulosclerosis. Finally, PCA inhibited levels of macrophage inflammatory protein-2 and monocyte chemotactic protein-1 in kidney tissue, demonstrating that it may inhibit macrophage infiltration, which is closely related to renal inflammation.
The results suggest that purple corn extract could potentially inhibit diabetic nephropathy and the researchers concluded that PCA may be potential renoprotective agent treating diabetes-associated glomerulosclerosis.
The full study can be read online.
