extracting alkaloids?

The material is  subjected to an alcohol extraction, eg with methanol or ethanol.

All materials such as ethanol, acetic acid or vinegar, ammonia and solvent should be free of detergents, perfumes, colors or other additives, these may affect the reaction or prove harmful. Electrical elements should be used for all heating as open flames are highly dangerous and likely to set everything alight. Excellent ventilation is also a necessity.
The plant material is dried, weighed  and ground as fine as possible.
Then soaked overnight in 50/50 ethanol (and /or methanol, 'methylated spirits') to acetic acid solution (white vinegar), pH  at 4. Then heated until boiling and simmered for an hour or so, then the liquid filtered off and kept. Then re-cover the material with water, or more of the above solution if readily available, and repeat this step, without soaking overnight. It may be repeated a third time, but most of the alkaloids should be in the liquid that is taken off the material. The plant material may be composted/ discarded after this.
http://mulga.yage.net/acacia/extract.html