Which statement best describes the role of mordant in hematoxylin staining?

• A. It Enables Binding of Hematoxylin to DNA
• B. It Dye Lipids
• C. It Fixes Tissues
• D. It Cleanses Stain

Answer: (A)

The main idea is that the mordant forms a bridge with hematoxylin to create a complex that binds strongly to tissue, especially to the acidic components of DNA in nuclei. In hematoxylin staining, the dye is oxidized to hematein and then combined with a metal mordant (commonly aluminum) to form a hematein–metal complex that has an affinity for the phosphate groups in nucleic acids. This is what produces the prominent nuclear staining seen in H&E sections. The mordant’s role is not to dye lipids, fix tissues, or cleanse the stain, so those statements don’t describe its function.