Spectrophotometry, Physiochemical Properties, and Histological Staining Potential of Aqueous and Ethanol Extracts of Beetroot on Various Tissues of an Albino Rat

BACKGROUND AND AIMS: Natural dyes and pigments are nontoxic, ecofriendly alternatives to synthetic counterparts and beetroot is one such natural dye. The red color of beetroot derived from betalain pigments confers great advantage to this plant. In this study, the physiochemical and spectrophotometric characteristics of beetroot as well as the histological staining potential of various tissues were carried out to determine its tissue specificity. METHODS: The aqueous and ethanol extracts of beetroot were prepared using distilled water and 95% ethanol, respectively. Spectrophotometry, pH, and concentration of both extracts were determined before histological staining with 10% neutral-buffered formalin-fixed, paraffin-wax-embedded tissue sections. Stained sections were viewed with a photomicroscope. RESULTS: The aqueous and ethanol extracts of beetroot were slightly acidic and soluble at concentrations of 381.5 mg/100 g and 253.7 mg/100 g fresh beetroot sample, respectively. Both extracts consist of three betalain pigments with absorbances at different spectrophotometric wavelengths, namely betaxanthins (475 nm), betanin (525 nm), and betanidin (575 nm). The maximum absorbance was 0.925 and 0.615 for the aqueous and ethanol extracts, respectively, at a peak wavelength of 525 nm for each extract. Both extracts stained various tissue structures such as muscles, mucins, red blood cells, keratin, and nerve fibers. CONCLUSION: Thus, beetroot stain is slightly acidic, contains betalain pigments, stains basic histological tissue structures, and can be used as an ecofriendly alternative to hematoxylin and eosin.