(-)-5,8-dihydroxy-2-(1-hydroxy-4-methyl-3-pentenyl)-1,4-naphthoquinone;the
major red paint derived from alkanet; used as an astringent, and in
cosmetics and foods; can be used as an indicator:
red at pH 6.8, changing to purple at pH 8.8 and
blue at pH 10.0;
also used as a
thick stain.
Synonym: anchusin.