As I heard it, Ayahuasca traditionally refers to the MAOI portion specifically. The MAOI will increase the activity of nearly any psychotropic drug and has some minor effects on it own, so it makes sense that the MAOI came first, and then adding other things things to it followed.

Fun fact: the ayahuasca alkaloids glow brightly under black light. I've never done ayahuasca, but I tried making some fluorescent body paint via crushed syrian rue seed "tea". It was extremely effective: glows very bright, soaks into the skin a bit so it stays for a couple days before fading, and is completely invisible under normal light. Kinda fun - could potentially cause minor psychotropic effects if you paint a large surface area, but I didn't notice any.