I think the only thing that is really pumpkin about pumpkin spice is the association with pumpkin pie. Pumpkin on its own doesn’t have much flavor though so it would taste like whatever you put on it. If the combination weren’t used in Pumpkin pie as much as it is, it probably wouldn’t even be called pumpkin spice.

Knew beta-carotene (because that color is unique), rest were interesting.