I saw your other post where you washed with acetone.  Have you tried multiple washes.  Root bark can be 10% essential oil.  It may take multiple extracts to remove these.  The alkaloids if in a salt form would likely not dissolve in the acetone (although some salts do).  It could very well be the alkaloids that have been found.  Also you seem not to make a distinction between psychoactive and psychedelic. 

This is why I think I always am skeptical as you claim everything is psychedelic when I think you really mean psychoactive.  Stimulant like is far different than psychedelic.  You seem to use them as if they are the same word. Do you have experience with other classes of psychoactive agents? 

I am skeptical of psychedelic effects but never the less I agree there could be trace actives.  I have not personally read the methods so I don't know.  An MAOI effect alone from the above two alkaloids may describe the effects.  Why not find the articles and isolate these alkaloids (as they would likely still be present after the MEK wash). Isolating the pure alkaloids would likely help clear this up.