The herb Foxglove has been used for centuries to cleanse wounds and Native Americans brewed its dried leaves in order to treat leg swelling caused by cardiovascular problems. Now, researchers have discovered that an active ingredient in Foxglove (digitalis) called digoxin, can improve the body’s own protective mechanism against heart failure and hypertension.
The study, conducted by researchers at the University of Michigan Health System, is published online in Molecular Pharmacology.
Although maintaining a healthy weight, being physically active and reducing salt intake can prevent hypertension, approximately 1 in 3 individuals in the United States have the condition.
The majority of treatments available today prevent excess hormone and stress signals that can cause heart failure and hypertension.
However, research has demonstrated that the body is able to keep excess stimulation in order by generating a family of inhibitors called RGS proteins.
Researchers set out to look for ways to “re-purpose” old medications in order to tap into this protective mechanism, which is lost among some people suffering from heart failure and hypertension.
Lead study author Benita Sjogren, Ph.D., a research fellow in the Department of Pharmacology at the University of Michigan, said: “We tested several thousand known drugs and bioactive molecules for a potential role in enhancing RGS2 and/or RGS4 expression and function and have identified a novel mechanism for digoxin.”
The researchers examined case histories collected by Dr. William Withering in 1775 and found that Foxglove contained the active ingredient digoxin. At present digoxin is a vital medication for treating individuals with congestive heart failure.
This new action of digoxin was discovered by treating engineered human kidney cells with thousands of known medications in a high-throughput screen at the U-M Center for Chemical Genomics. The researchers then found that digoxin has similar actions in isolated mouse blood vessel cells.
Senior study author and pharmacologist Rick Neubig, M.D., Ph.D., professor of pharmacology, associate professor of internal medicine, and co-director of the Center for Chemical Genomics at the University of Michigan, explained:
“In addition to test tube studies, low dose digoxin, the active ingredient of digitalis, was able to increase RGS2 levels in the heart and kidney.
This new action of digoxin could help explain that fact that low doses seem to improve the survival of heart failure patients. It also suggests new uses for low dose digoxin for other drugs that can activate this protective mechanism.”
Neubig’s lab focuses on RGS proteins and how they impact cancer and immunity, heart, and brain function. In addition they examine how these proteins can be exploited in therapeutics.
Written By Grace Rattue