From Scientific American:
A painkiller with just one of these properties would be great, but Majumdar thinks he has stumbled onto a class of chemicals that might have them all. They are found in kratom, a plant that the U.S. Drug Enforcement Administration intends to effectively ban from the U.S. in an emergency move as early as September 30. Without legal access to it, research on some of the most promising leads for a better painkiller may grind to a crawl.
Kratom comes from the Mitragyna speciosa tree native to parts of Southeast Asia, where people chew the leaves for a light, caffeine-like jolt of energy or as a traditional medicine for ailments ranging from diarrhea to pain. Kratom has been illegal since 1943 in Thailand, where it is believed to be addictive. Case studies have suggested that suddenly stopping regular kratom use may lead to withdrawal symptoms—but they are widely considered milder than those associated with opioids.
Majumdar first learned about kratom via a Web search a couple of years ago. By then there were stories in the West about how kratom tea could be used to manage pain—and to mitigate brutal opioid withdrawal. That caught Majmundar’s attention, and he found research from the 1970s that described some of the basic biochemistry of kratom’s two primary psychoactive compounds, mitragynine and 7-hydroxymitragynine, as well as one more molecule called mitragynine pseudoindoxyl, which is produced when kratom ferments. “We got excited because the chemical structure is almost completely unrelated to that of commonly used opioids,” says Andras Varadi, a colleague of Majumdar who is a medicinal chemist at Columbia University and Sloan Kettering.
When Majumdar and his team started studying the compounds in the laboratory, they realized all three molecules were binding to the mu-opioid receptor—one of three known kinds of opioid receptors …