Hello. I am new to the forum and to alkaloid extraction. I'd like to try practicing the various extraction techniques on plants that are more readily available in my area (central Ohio) before either buying something like MHRB powder or foraging for Desmanthus illinoensis this spring. Can anybody suggest some plants and name some of the useful chemicals one might extract from them, and in what concentrations?

Welcome on the forum

You can do extractions almost everything you can find in a supermarket.
Going to extract piperine from pepper, curcumine from curcuma, theine from tea, caffeine from coffee ..
You can find easily on the internet what you want about theses component of common daily food, as videos on youtube.
Depending on where you want to go (crystalline extract, or crude extract ..) and the materials you have (glassware, soxhlet ...) you should find a suitable procedure for you.

If you're on a path to learn chemistry and related procedures, you can start very easily with water extracts (as tea), then try to learn how to extract from this extract if you're confident with. Starting "playing" with safer & easily available chemicals (as vinegar, baking soda, oil for example) can help you understand what's going in the matter, and you may be near the path of your objective.
You can do some other work as an egg oil ( http://forum.alchemyforu...ive/index.php/t-330.html )
In anyway, it's allway by practising you'll master your technique and give the most of you in the matter

Feel free to introduce yourself & share your work

Peace