noun

• A red colouring matter obtained from the root of the plant alkanet, Alkanna tinctoria, used as a food colouring and in cosmetics; also called alkannin.

  Systematic name: 5,8-dihydroxy-2-[1-hydroxy-4-methylpent-3-enyl]naphthalene-1,4-dione; C₁₆H₁₆O₅.