The leaves have turned, and there’s a chill in the air. Summer is over and fall is well underway. Fewer people are outside tending to gardens and lawns, which means fewer incidences of poison ivy, oak or sumac exposure. That’s a huge relief for the more than half of all adults who are allergic to the oils of these plants.
Exposure to the “toxic trio” of plants is more than a nuisance to some people. Thousands of people get such a bad rash that they have to see a doctor and can’t go to work or school. And very little of the oil is necessary to cause problems — it takes only 0.04th of a drop to trigger a reaction. The oil remains active for five years or more, even on dead plants. The oil is not only on leaves, but on the stems and roots of the plants, and it is invisible.
In a recent paper in The Journal of Organic Chemistry, researchers report that they’ve developed an inexpensive spray that could show that poison ivy, oak or sumac oil is on your skin, tools, the family pet or on leaves of suspicious-looking plants. That would allow you time to wash off the oil or avoid further contact altogether.
They describe the development of a spray that, when applied to leaves of poison ivy, oak and sumac, reacts with urushiol, the toxic oil produced by those plants. When exposed to an ordinary fluorescent light, the spray glows if urushiol is present, revealing the location of the oil. “This constitutes the groundwork for the future development of a spray to detect urushiol to avoid contact dermatitis,” the scientists say. They also say that the spray could have biomedical applications in detecting substances similar to the compounds in the oil, such as neurotransmitters involved in Alzheimer’s disease and Parkinson’s disease.
The image on the left (a) shows fresh poison oak leaves. After the researchers exposed the leaves to the new spray, they pressed the leaves against a paper towel and produced an imprint (b) that shows the location of the urushiol using a fluorescent light.
Credit: American Chemical Society