Which pigment is more common in bloody tissue: Hematein or Hematin?

• A. Hematin
• B. Hematein
• C. Both
• D. Neither

Answer: (A)

The key idea here is understanding what forms as a pigment inside tissue containing blood. Hematoxylin is a natural dye used for staining; when used in staining, it is oxidized to hematein, which then binds with a mordant to create the blue-purple nuclear stain. However, within actual bloody tissue, pigments arise from the breakdown of blood and heme. Hematin is the iron-containing pigment formed when hemoglobin or heme is oxidized, and it commonly appears in hemorrhagic or blood-rich areas as a brown-black pigment. Hematein, by contrast, is not a pigment produced in tissue; it is the chemical form involved in the staining reaction. Therefore, hematin is more common in bloody tissue.