Evaluation of Turmeric (Curcuma longa L.) extract as a natural alternative to Eosin in histopathological staining

Background: Synthetic dyes like eosin are widely used in histopathology but are associated with health hazards and environmental concerns. Objective: The study aims to evaluate the staining potential of Curcuma longa L. (turmeric) extract as a substitute of eosin in standard hematoxylin and eosin (H&E) staining. Methods: Two techniques were used to slice and stain archival paraffin-embedded tissue samples: the conventional H&E process and a modified variant that substituted an alcoholic extract of turmeric for eosin. The staining quality of various tissue components such as keratin, collagen, muscle, salivary glands and epithelium was evaluated. Stained slides were assessed for cellular outline, cytoplasmic details, nuclear clarity and morphology using a three-tier grading scale (poor, good, excellent). The staining quality scores were compared using the Mann-Whitney U test. Results: The turmeric produced a distinct yellow to brownish-yellow cytoplasmic staining with excellent differentiation. Significant differences were observed for collagen (U = 67.5, p = 0.0049) and salivary gland staining (U = 67.5, p = 0.0049) while keratin (U = 112.5, p = 0.0658), epithelium (U = 104.0, p = 0.7238) and muscle (U = 106.5, p = 0.778) did not show statistically significant differences. Although eosin provided superior sharpness in some tissue structures, turmeric demonstrated comparable staining quality across most components. Conclusion: This fining support the use of Turmeric as a natural and non-toxic alternative, making it a suitable option for laboratories seeking sustainable staining methods.