Assessing the use of Lawsonia inermis and Hibiscus sabdariffa aqueous extracts as a possible Substitute for eosin stain in paraffin-embedded tissues

Abstract

Eosin has been widely used as a counterstain to hematoxylin; however, it is a synthetic stain that can pose a possible threat to the ecosystem because it is toxic and non-biodegradable. Continuous use of this dye can cause various health hazards to the laboratory technicians, pathologists, and scientists working in the laboratory. The dye is also known to be costly. Since eosin is known to be a synthetic stain that can be harmful, costly, and not readily available, and development of natural histological stain is justified if the natural stain is harmless, cheaper, and readily available. Therefore, this research work may bring out natural dye products which may serve as a counterstain replacing eosin in the Hematoxylin-Eosin staining technique. With the rising attention given to the ecosystem, the need to replace synthetic dyes with naturally available dyes due to their eco-friendly nature is pertinent. Premised on the result of this study it was concluded that henna (Lawsonia inermis) and roselle (Hibiscus sabdariffa) can be used as substitutes of eosin stain. The naturally acidic nature of their aqueous solutions at the tested concentrations enabled their staining of cytoplasm. Further studies for suitable mordant and/or accentuators that would increase the staining intensity as well as reduce the staining time, thus making henna and roselle a potent stain are recommended. Aqueous extracts of henna and roselle should be considered for use as an alternative when there is a shortage or absence of eosin in histopathology laboratories