Would definitely be interesting to compare alkaloid composition of the roots to the branches. And to determine the exact composition of each one. And also other closely related species. There is a related species called Tabernaemontana undulata also which grows in the same area. Ushpawasha sanango is the common name. There are more related species I'm certain, I've seen one with orange flowers (instead of the commonly seen white flowers). I can harvest a little of that, it grows by my friends house.
My friend who lives deep in the jungle harvested these batches, where he lives, this tree grows everywhere. The natives of the jungle here are experts at finding and identifying the trees. That would be amazing if I could post some samples to you. If you could get a HPLC, we can learn a lot.
Thanks for the tip about methanol:ammonia.