THAT'S THE WHY:Castor oil – it might not be the most pleasant of remedies, but it has reportedly been in use for millennia.
One of its effects is to relieve constipation, but how can an extract from the seeds of the plant Ricinus communis stimulate the gut and act as a laxative? A new study in Germany has pointed to a molecular mechanism, in mice at least.
“It has been known for many years that a certain ingredient, namely ricinoleic acid released from the oil in the intestine, is responsible for the effect,” said researcher Sorin Tunaru in a release from the Max-Planck Institute.
“However, until now it was assumed that this acted via a local irritation of the intestinal mucosa. We have now been able to show that it is actually a pharmacological effect.
They did this by turning off a biochemical receptor called EP3 on certain cells in the mouse intestines: mice that didn’t have this receptor on smooth muscle cells of the gut didn’t experience laxative effects if they were given castor oil or ricinoleic acid.
The researchers wrote online in the Proceedings of the National Academy of Sciences last week that the use of castor oil as a laxative has declined in conventional medicine and that the focus has been on side effects such as “the unpleasant taste, cramps and danger of fluid and electrolyte losses”.
But they say that their findings on ricinoleic acid and EP3 may point to new ways of getting the gut going again: “The unexpected, highly specific mechanism of action may promote a re-evaluation of the medical use of castor oil and suggests novel approaches to increase intestinal motility.”
