[proto]

to extract water soluble plant alkaloids, you can use either an alcohol/water method, or an acid base extraction. if you want a concentrated extract, then if you want to leave the waxy, resinous material behind and only get the "actives" an acid-base extraction is a good choice, but what do you do when you have lipophilic alkaloids that are only soluble in non-polar solvents, like you find in most essential oils? it's ok if you only want an extract, but how would you go about concentrating them? or are there no waxy or resinous materials to worry about in these sorts of liquids? if not then you could use hexane and then evaporate it off? i must admit i haven't tried it yet, for once i was thinking ahead! guess i was wondering what the non-polar equivalent is of a standard hcl=naoh extraction? thanks.

[kiwi]

you can crash out straight chain waxy things selectively as their urea complexes - does this help? or alternatively if you know what you are after is an alkaloid in the technical sense (ie. has a basic N), i'd dissolve it all up in ether, and add etheral or gaseous HCl. the waxy stuff will stay in solution, and the alkaloid-HCl salt will ppt out of the ether. Filter and serve.

[kremar]

essential oils are extracted by steam distillation.

this procedure works great for compounds that are both:
1) inmiscible in water
2) volatile (have a high vapour pressure)

waxes, having lower vapour pressures, will be left behind.
essential oils, being perfumated, are composed of compounds with high vapour pressure.