protocatechuic acid, pca molecule. it is 3,4-dihydroxybenzoic, phenolic acid, metabolite of antioxidant polyphenols, catechol, is

acid antioxidant atom atomic ball benzoic carbon catechol chemical chemistry dihydroxybenzoic drawing flat formula green hibiscus hydrogen icon illustration metabolite molecular molecule organic oxygen phenolic polyphenol protocatechuate protocatechuic render rendering structural structure tea