If the seeds do contain any active alkaloids at all, I strongly suspect it would be in extremely negligible quantities, and the quantities required for any kind of effect would be very vast indeed. I have unfortunately eaten a large quantity of Iboga whole root on one occasion several years ago now, and active alkaloids were negligible in that, but I did manage to poison myself quite nastily and was unable to walk for three days! So it's really only the root bark you want, specifically the second layer of root bark, where most of the actives reside.