I feel when we test any Plant extract, logically we do not consider them just plant extract it is always consider as drug. Any plant extract having an number of molecules and their combination effect of the molecules present in that extract. So in drug development process we always try to isolate that particular molecule or try to synthesize that chemically which resemble that structure.

In the end it comes to stage where mostly look for the concept i.e., "LOW CONCENTRATION SHOULD GIVE MAXIMUM EFFECT; ITS LIKE A REDUCTION IN DRUG LOAD INTO THE BODY. PARALLELY PHARMACODYNAMICS AND PHARMACOKINETICS  OF ANY DRUG  HAS TO BE CONSIDERED.

So, if plant extract from where this drug discovery story starts and less concentration showing higher effect. logically its good and positive only.

Also and very important it will keep the final product price under control. 

thank you Mr Mandal