Last year I mentioned a paper that described the well-known drug tramadol as a natural product, isolated from a species of tree in Cameroon. Rather high concentrations were found in the root bark, and the evidence looked solid that the compound was indeed being made biochemically.

Well, thanks to chem-blogger Quintus (and a mention on Twitter by See Arr Oh), I’ve learned that this story has taken a very surprising turn. This new paper in Ang. Chem. investigates the situation more closely. And you can indeed extract tramadol from the stated species – there’s no doubt about it. You can extract three of its major metabolites, too – its three major mammalian metabolites. That’s because, as it turns out, tramadol is given extensively to cattle (!) in the region, so much of it that the parent drug and its metabolites have soaked into the soil enough for the African peach/pincushion tree to have taken it up into its roots. I didn’t see that one coming.

The farmers apparently take the drug themselves, at pretty high dosages, saying that it allows them to work without getting tiree. Who decided it would be a good thing to feed to the cows, no one knows, but the farmers feel that it benefits them, too. So in that specific region in the north of Cameroon, tramadol contamination in the farming areas has built up to the point that you can extract the stuff from tree roots. Good grief. In southern Cameroon, the concentrations are orders of magnitude lower, and neither the farmers nor the cattle have adopted the tramadol-soaked lifestyle. Natural products chemistry is getting trickier all the time.