When a blend is said to have aromas of cherry, vanilla, tonquin, chocolate etc. Is it infused with extracts from the actual fruits or sweets or are they using something chemical that mimics these flavors?
Interesting question, and somewhat in my previous life's field (biochemistry).
There are two ways to "capture" a smell: either you need to extract it from its natural source, or break down what is in the natural source and reconstitute it in a more controlled fashion in a lab.
The first "method" is what's been employed throughout human history, and it's major
drawback is that it is extremely expensive in materials and labour. This is because aromatic molecules are present in minute amounts, therefore you need a lot of starting material, and what you end up with needs to be concentrated a lot to end up with something workable. Still it is achievable, all the way back to ancient Egypt, India, Greece etc.
Aromatic molecules are, more often than not, hydrophobic, meaning you need to use oils or alcohols to extract them out of mint leaves, rose petals, cinnamon bark, vanilla bean etc.
The major
advantage of this method is that along with the "main" molecule (e.g., eugenol in basil and cloves), there are a myriad additional aromatic molecules in even smaller amounts which give the plant its bouquet. However since you're dealing with a natural material the results can be inconsistent, something really unacceptable in any sort of commercial product.
The second method needs modern technology (gas chromatography, among others), and is based in the concept of first making e.g., a rose extract, and then breaking it down to ALL its chemical constituents to understand what it's made of (i.e., to identify and characterise all chemical molecules that were pulled out of the rose petals), and find out their exact proportions, then the second step is to recreate the exact same mixture in a laboratory flask, in order to have your pure "rose essence". The major
advantage is that this extract is ultimately much cheaper to produce, and light years more consistent than anything that could be obtained by extraction and concentration. The
drawback is that to an experienced smeller/taster it will feel fake, empty somehow, as it can be missing some of the smaller molecules found in trace amounts in the natural extract. A good case in point was using vanillin in the lab, it is the pure major component of the vanilla bean's smell, and very cheap to buy, however although the first smell was intense vanilla, it lacked the depth, warmth and sweetness of natural vanilla extract. It's almost like looking at a picture of someone vs meeting them in person.
That book (
http://www.leffingwell.com/download/TobaccoFlavorBook.pdf) took me back some years. You'll see the flavour notes are not definitive, they are "green, hay"... What does "green" smell like? It is just what invokes in us.
Now, I realise this is not answering your question, as posted above, it is possible that some manufacturers actually use natural extracts, but I'd suspect that they are the minority considering the huge gap in terms of expense, and risk in terms of consistency vs using artificial flavour mixtures.