Amazon offers several "Bubble Gum Flavoring" or "Bubble Gum Extracts" in both "Natural" and "Artificial" varieties. While the manufactures don't list specific ingredients this is one recipe:
Here is my basic bubble gum recipe based on "10 parts..." the key is really in the wintergreen, cinnamon and clove. Fruits can vary a bit-but you will find this to be the "ticket."
3 parts banana flavor 3 parts pineapple flavor 2 parts wintergreen, 1
part cinnamon and 1 part clove.
As I said Bubble Gum flavor is complex and not just one or two notes.
The oldest formula included a fruit like "king fruit" or "passion
fruit" but I find most any tropical flavor will pull through.
Whether you (or various manufacturers) choose to use "natural" or "artificial" versions of these flavoring is an individual choice, but it is clearly not limited to "Just artificial chemicals".