What is haematoxylin?

HAEMATOXYLIN:

• Derived from the wood Haematoxylum campechianum.
• It means bloodwood  - refers to the dark red colour (Haemato -  blood, xylon- wood)

• Campechianum  refers to the coastal city of Campeche on the Yucatan Peninsula, the locality of the heart wood.

Pic: Google

If Haematoxylum is red, how is haematoxylin blue?

• Haematoxylin has little or no staining capacity.
• Haematoxylin is oxidised to haematein which gives the blue colour.
• Oxidation - two methods - 1. Natural 2. Chemical

Haematoxylin versus Haematein:

If hematein is the dye and haematoxylin needs to be oxidised before it can stain, why not use hematein in the first place?

• If we start with hematein, oxidation will start to diminish the staining capacity right from the start, shortening the working life of the solution ☺☺