There are many plants that no amount of research by the largest pharmacetical companies can determine the which exact ingredients in the exact proportion are the active ingredients. Some are simple such as aspirin. Dicovered by Bayer while on a trip to the Far West of the U.S. and noticed the Indians chewing a few twigs for toothache, headache, etc. He laughed and ridiculed the idea until he tried it. Aspirin is now the world's largest selling drug and the only one that has never had a license granted, or passed any official testing. Devil's Club compound is another one. The only organization that recognizes it is the British medical society. If used correctly it can CURE diabetes. Not just ease the symptoms, but cure it. The american AMA denies it has any medicinal value.
Hawthorne, Foxglove, Comfrey, and many others are effective for other problems such as high blood pressure, arhythmic heart, esophageal entritius. Feverfew is and has been for years recognized as a cure for Migraine and again, the drug companies cannot duplicate it because, like Devil's club, there are too many compounds and while it varies in nature according to the soil it grows it, it is still good. Some regions better than others. I have seen too many people cure their migraine headaches to dismiss the idea as cavalerily as "if it worked, the drug companies would make millions" because the drug companies have tried and failed to replicate the compound. Sometimes nature is better than man.