Para Aminobenzoic Acid (pABA)

PABA is a white grey crystalline substance that is only slightly soluble in water. It consists of a benzene ring substituted with an amino group and a carboxyl group. PABA is mainly prepared by two routes: reduction of 4-nitrobenzoic acid and the Hoffman degradation of the monoamide derived from terephthalic acid. Food sources of PABA include liver, brewer's yeast (and unfiltered beer), kidney, molasses, and whole grains.

PABA is an intermediate in the bacterial synthesis of folate. It has been referred to as Vitamin B_x. Some bacteria in the human intestinal tract such as E. coli require PABA. Therefore, in humans, PABA is not a vitamin and is considered nonessential.