Flavonoids from the red alga <i>Acanthophora spicifera</i>

Abstract Two new flavonoids, acanthophorin A (1) and acanthophorin B (2), along with three known compounds tiliroside (3), (‐)‐catechin (4) and quercetin (5) were isolated from the red alga Acanthophora spicifera . The structures of 1 and 2 were determined to be kaempferol 3‐ O ‐α‐ L ‐fucopyranoside (1) and quercetin 3‐ O ‐α‐ L ‐fucopyranoside (2) by spectroscopic methods. Both 1 and 2 showed significant antioxidant activity.