hey there arimane
i too am in the process of researching this plant and 5htp
this is the best source of info ive found on the plant so far:
http://www.ijplsjournal.com/issues PDF files/july2010/8..pdf
and it covers 5htp pretty well as well...
i'm in the process of designing my own site that will compile my interests of ethnobotany along with my other interests... when completed i will post the link in this message and more info on 5htp will become available!
ive personally been taking 5htp for 5 days now and have noticed awesome results! i got so excited about it before my order arrived i managed to find a very rare seedling for sale on an australia website and didn't hesitate to buy it... the next day they were out of stock!
the above link was a god send as i have struggled to find any information on growing it until now... hopefully i can keep it alive and start harvesting my own seeds within 12 months!
i am currently studying a bachelor of health science in naturopathy btw.. so this stuff is right down my alley!