Lawsonia inermis (Henna) extract: A possible natural substitute to Eosin stain

Background: The extensive evolution of Histopathology can be mainly attributed to the availability of a wide array of stains. Staining has made possible the identification of various tissue structures under microscope aiding in appropriate diagnosis. However, the present era of increasing importance to ecology has necessitated the requisite for natural dyes. Unlike synthetic dyes, natural dyes are less toxic, biodegradable and are eco-friendly. Haematoxylin and Eosin are the routinely used stains in histopathology wherein eosin is a synthetic stain. Various attempts have been made to substitute eosin with a natural dye, one among which is Lawsonia inermis (Henna). Nevertheless, the staining efficacy of henna extract on FFPE (formalin-fixed paraffin embedded) oral tissues, as a counterstain to haematoxylins is yet to be determined. Aim: The study aims to analyse the use of Lawsonia inermis extract as a possible substitute for eosin stain in paraffin embedded oral tissues. Methodology: The colouring component of dried leaves of Henna was extracted using Maceration and Soxhlet method. 4µ sections of 20 paraffin embedded oral tissues of normal oral mucosal tissues and OSCC tissues each, were stained using the extract and counterstained to haematoxylin and studied for its staining efficacy. Statistical Analysis: Chi square test was done and noted for any significant results. Results: On comparing the staining efficacy of henna while using different extraction methods, Soxhlet method was better than maceration method by 20%, however statistically the results were insignificant. Staining efficacy of Henna with and without the mordant were statistically significant wherein staining with mordant gave inferior quality stain. Henna stain, when compared to eosin, comparable results were found, with eosin being slightly better by 15%. Conclusion: In this era of increasing importance to ecology, henna may well prove to be an effective alternative to eosin in histological sections of normal and pathological tissues as both the stains gave comparable results.