Iron-Roselle: A Progressive Nuclear Stain Substitute for Hematoxylin

Abstract

Roselle, the dried calyces of Hibiscus sabdariffa L., is a food colorant used in many tropical countries. A simple hot-water extract of roselle, with added ferric chloride (FeCl₃.6H₂O) and acetic acid, provides a progressive blue stain for cell nuclei comparable to that seen with hemalum. Dry, red calyces of H. sabdariffa were ground with a binatone blender. To 10 g of the ground red calyces of H. sabdariffain a conical flask, 200 mL of distilled water was added and brought to boil to create the brilliant red-colored extract. It was immediately allowed to cool and filtered with a Whatman filter paper to give a clear H. sabdariffaextract. The extract staining solution was compounded as follows: 100 mL of clear H. sabdariffa extract, 5.0 g of sodium chloride, 1.2 mL of 10% ferric chloride solution, and 3.0 mL glacial acetic acid. The solution was used to stain paraffin sections of formaldehyde-fixed tissues at 4 microns along with parallel hematoxylin and eosin (H&E) stains for a control. Results showed that staining of nuclei with the extract solution was comparable with those sections stained with H&E. It is therefore suggested that the extract solution could be a progressive nuclear stain substitute for hemalum in H&E procedures due to its domestic availability, ease of preparation and use, resistance to fading and above all its good nuclear staining properties. (The J Histotechnol 31:57, 2008)

Submitted October 23, 2007; accepted with revisions April 11, 2008

Keywords:

• roselle extract
• anthocyanin
• hematoxylin