10/24/2021: I have been working with protocatechuic acid for 15 years. It has so many potential and real health benefits, I am cautious to say. However, the continuing report support the many varied real and potential uses.
See: https://www.sciencedirect.com/science/article/pii/S1043661820314171
I have assigned my US patent rights on protocatechuic acid for nutraceutical application to DrJsNatural.com. The Dr J is for Jaqueline Ng who has a doctorate in pharmacology.