Multiple choice Which of the following pairs is not correct? Henna : Shikonin Madder : Alizarin Gallnut : Tannin Cutch : Catechin Logwood : Hematein Reveal answer Fill a bubble to check yourself A Correct answer Explanation Henna contains lawsone, a naphthoquinone compound, as a colouring agent. Shikonin is the principal colouring pigment of purple gromwell (Lithospermum erythrorhizon).