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

protocatechuic acid pca molecule it phenolic metabolite antioxidant polyphenols catechol dihydroxybenzoic polyphenol protocatechuate benzoic green tea hibiscus drawing flat icon hydrogen carbon oxygen organic chemistry structural formula atomic structure chemical atom molecular illustration vector found model