All of the above may be related to non-detection. It is recommended that the preparation be dissolved in a small amount of water and then refluxed with ether. This has a direct relationship with the type of extraction solvent in the preparation of your particles, if the extraction is water, it is normal to not detect, because ursolic acid is poorly soluble in water, which is often encountered in our work. We suggest acid hydrolysis, if it can not be detected, we can provide research information. May I ask how to hydrolyze the ursolic acid? In which step to hydrolyze? Can you send me a specific experimental procedure? Thank you granules should be able to dissolve with water, then dissolve it, adjust the acid, and extract it with ether. The best solvent to extract ursolic acid is 95% ethanol, methanol can also.