I've tried to extract rosmarinic acid using a few methods and I wasn't successful.
I used the method of the British Phamacopeia and it doesn't function, solvent extraction (using Methylene Chloride after Ethyl Acetate and Methanol) but in comparison to the standard in TLC the molecule doesn't appear (movil phase: Methylene Chloride:Ethyl acetate:acetone:formec acid (10:80:25:8,5) )