New investigations on hematoxylin, hematein, and hematein-aluminium complexes

Abstract

Analytically pure hematoxylin (Htx), pentaacetylhematoxylin (PAHtx), and hematein (Hm) were isolated and characterized by 1H-NMR spectroscopy. The VIS/UV spectra of Htx and Hm were recorded in MeOH and in H2O at various pH values. The molar extinction coefficients of the long wavelength absorption bands are reported. The pKa value for the 1st acidic dissociation step of Hm has been determined from the pH dependency of the absorption spectra of Hm in aqueous buffer solutions. Finally, the absorption spectra are qualitatively discussed.

Electrochemical oxidation of hematoxylin – Part 1: Experimental and theoretical studies in an aqueous acidic medium

“…The p-quinonemethide III is more stable than the o-quinone IV and the o-quinone V. This is in agreement with previous work on the oxidation of 4-alkylcatechols to o-quinones which were shown to undergo tautomerization to p-quinonemethides [30][31][32][33][34]. In accord with previous published data on the structure of hematein (1ox) [2,8,35], its structure should be that of the most stable tautomer I.…”

Dyes and other colorants in microtechnique and biomedical research

“…These observations suggest that histones, the strongly basic proteins associated with DNA in chromatin, constitute the substrate of nuclear staining by haemalum. This conclusion conflicts with the results of Bettinger and Zimmermann [14,50] who conducted thorough NMR and UV–vis spectroscopic studies of aluminium–haematein complexes. These authors showed that a haemalum solution at pH 3.2, known to contain cationic dye–metal complexes, stained DNA and RNA in fixed cell cultures.…”

“…This conclusion conflicts with the results of Bettinger and Zimmermann [14,50] who conducted thorough NMR and UV-vis spectroscopic studies of aluminium-haematein complexes. These authors showed that a haemalum solution at pH 3.2, known to contain cationic dye-metal complexes, stained DNA and RNA in fixed cell cultures.…”

Influence of Histochemical and Immunohistochemical Stains on Polymerase Chain Reaction

“…Conversely, the hematoxylin and May-Grunwald stains considerably inhibited the PCR amplification. The untoward effect on PCR by the hematoxylin stain has been described, and two possible explanations are proposed: the dye may bind to DNA and subsequently interfere with proteinase digestion (8,18,19), or it might influence divalent cation (Mgϩϩ) concentration that is important in maintaining the Taq polymerase activity (18,20). Because the present CYCLE min may depend on either the state of template DNA or the process of PCR amplification and the CONC max may depend predominantly on the latter, the lower CYCLE min and CONC max values in the hematoxylin-stained samples in this study suggest that both mechanisms may be responsible.…”