Instead of boiling whatever plant for long periods of time, I think an alternative is boil some water, mix it in with your plant material in a heat retaining thermas, and shake the heck out of the container for however long you want. The water stays near boiling for a couple hours. I figure the shaking would help to break bonds, should there be any, between alkaloid salts, and plant material.

One would still have to check the acid compability (if used) of the thermas and do multiple "pulls" but yeah sound like an idea.