from the certain-kinds-of-weed-is-catnip-for-humans dept.
Anyone who has seen a cat experience catnip knows that it makes them go a bit wild—they rub in it, roll on it, chew it, and lick it aggressively. It is widely accepted that this plant, and its Asian counterpart, silvervine, have intoxicative properties, but this might not be the only reason that cats rub on and chew the plants so enthusiastically. Researchers in Japan have found that when cats damage catnip, much higher amounts of strong insect repellents are released, indicating that the cats' behavior protects them from pests. This study appears in the journal iScience on June 14.
Catnip and silvervine leaves contain the compounds nepetalactol and nepetalactone, iridoids that protect the plants from pests. To see how cats' behavior was affecting the chemicals released by the plants, Miyazaki worked with chemists at Nagoya University. "We found that physical damage of silvervine by cats promoted the immediate emission of total iridoids, which was 10-fold higher than from intact leaves," says Miyazaki.
[....] To test if the felines were reacting to these compounds specifically, the cats were given dishes with pure nepetalactone and nepetalactol. "Cats show the same response to iridoid cocktails and natural plants except for chewing," says Miyazaki. They lick the chemicals on the plastic dish and rub against and roll over on the dish."
"When iridoid cocktails were applied on the bottom of dishes that were then covered by a punctured plastic cover, cats still exhibited licking and chewing even though they couldn't contact the chemicals directly," says Miyazaki. "This means that licking and chewing is an instinctive behavior elicited by olfactory stimulation of iridoids."
A form of catnip for Chinese bears would cause pandamoanium.