According to a study published in the American Chemical Society’s (AMS) Journal of Medicinal Chemistry, the extract interrupts the passage of sodium and calcium ions through the membrane protein Na/K-ATPase in rats.
A subunit of this protein – called α4 – is uniquely found in sperm cells.
By removing a sugar group from ouabain, and replacing its lactone group with a triazole group, scientists created a derivative to target α4, and inhibit the cells’ ability to swim – an action required to fertilise an egg.
“The compound had no toxicity in rats”, reported the AMS, adding that the contraceptive effect should be reversible because α4 is only found on mature sperm cells.
“That means sperm cells produced after stopping treatment with the ouabain derivative should be affected,” said the AMS.
The University of Minnesota’s Gunda Georg told us ouabain is commercially available from suppliers such as Sigma-Aldrich – a US subsidiary of Merck KGaA.
“We are purchasing the ouabain that we use. It is quite expensive,” she said.
The researchers are now working to initiate preclinical mating studies in animals, before toxicology studies can be conducted, she told us.
From there, the researchers will be seeking US Food and Drug Administration (FDA) approval for a clinical trial.
Georg told us the university has a patent on the compounds reported in the paper.
“The patent could be licensed to a company,” she added.