Generally speaking, you may be able to get a miniscule amount of alkaloids out if they are in free base form, but most is going to be trapped in the cellular structure of the plant material and unlikely to volatise very well, unless you burn it in which case you'll get all sorts of oily combustion product shit ("tar") condensing and contaminating the tiny amount of desired compound that may come out. Much easier and more efficient to do a a/b extraction for protonatable amine-type alkaloids or a steam distillation or solvent extraction for essential oils etc. That solvent, whether water or organic, helps pull soluble compounds out of the plant material and into solution. Solvent extraction is quite efficient if you choose your solvent and processing conditions well. For example, just think how well a solvent such as hot water extracts caffeine from tea or coffee. Sure it pulls some tannins and stuff too, but it leaves 99+% of the depleted plant material behind. That's a pretty efficient extraction.
I don't see your example working very well, but It's good to think outside the box.