Vinpotecine is a derivative from a compound found in the lesser periwinkle plant:
If you ever went to one of those "smart bars" in the late 90's, theres a good chance you tippled some vinpocetine. I'm not sure whether it's actually effective, but people have looked at it for everything from Alzheimer's, to a prophylactic drug in stroke patients, to something for people who just want to feel a little smarter ("nootropics").