Lawsonia inermis (henna) extract: A possible natural substitute to eosin stain

Abstract

Lizbeth Raju, Shwetha Nambiar, Dominic Augustine, Sowmya S. V., Vanishri C. Haragannavar, Ashok Babu,Roopa S. Rao

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. Hematoxylin 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 formalin-fixed paraffin-embedded oral tissues, as a counterstain to hematoxylins is yet to be determined. Aim: The study aims to analyze the use of Lawsonia inermis extract as a possible substitute for eosin stain in paraffin-embedded oral tissues. Methodology: The coloring component of dried leaves of henna was extracted using maceration and Soxhlet method. Four micro sections of 20 paraffin-embedded oral tissues of normal oral mucosal tissues and Oral squamous cell carcinoma (OSCC) tissues each were stained using the extract and counterstained to hematoxylin 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, the Soxhlet method was better than the maceration method by 20%, however, statistically the results were insignificant. Staining efficacy of henna with and without the mordant was statistically significant wherein staining with mordant gave inferior quality stain. When henna stain was 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