Avenanthramides (anthranilic acid amides), a class of compounds found in oat at very low concentrations, have been reported to have antihistaminic activity. Indeed, the current authors have previously demonstrated the anti-itch and anti-redness efficacy of three naturally occurring avenanthramides: avenanthramides A, B and C. Now the authors report on the development and efficacy of four synthesized avenanthramides: avenanthramides D and E and dihydroavenanthramides D and E.
These various avenanthramides differ in the substituents on the cinnamic acid and anthranilic acid rings. Avenanthramides A, B and C are also known as avenanthramide Bp, Bf and Bc, respectively, where p, f and c are appendices for the individual cinnamic acid moieties; p means para-coumaric acid, f means ferulic acid, and c means caffeic acid. Avenanthramides D and E have the same substitution pattern in the cinnamic acid moiety as A and B and only differ in the anthranilic acid part.