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I would recommend you start this book Biochemistry and Molecular Biology of Plants

Now for what you are looking for specifically, is to investigate in articles about the metabolite that you want to extract and identify.

My favourite book on this subject is:

Jean Bruneton, Pharmacognosy, phytochemistry, medicinal plants, published by Technique & Doc in 1999. It is becoming dated in some respects, but it is still an invaluable handbook, although hard to find and expensive.