please be careful with Gramine..  I would research way more into gramine before bioassay...  For example I've read that possibly it can be separated from dmt by a very selective non-polar such as heptane, but probably not naphtha, which would carry gramine also..    I've also heard that gramine decomposes at higher temperatures so smoking it wouldnt be a problem but oral ingestion could..  I have no idea if these two affirmations are true, just an example of how there's some information out there and you should def research more because gramine (or other unknown alkaloids) might be very toxic.

I would also use a LOT of lye in the basifying step because high pH is known do destroy some alkaloids (but not dmt), but this is only a guess that it would be of benefit in your situation.  So defat at acid stage, high pH in base stage, pull with naphtha or whatever, and recrystalize with heptane, and start the bioassays with VERY small vaporized doses might be a bit more prudent way of going with this, but maybe still not enough,  so please do your research on gramine and other possible dangerous alkaloids in phragmites australis