Novel β-cyclodextrin–eosin conjugates

Abstract

Eosin B (EoB) and eosin Y (EoY), two xanthene dye derivatives with photosensitizing ability were prepared in high purity through an improved synthetic route. The dyes were grafted to a 6-monoamino-β-cyclodextrin scaffold under mild reaction conditions through a stable amide linkage using the coupling agent 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride. The molecular conjugates, well soluble in aqueous medium, were extensively characterized by 1D and 2D NMR spectroscopy and mass spectrometry. Preliminary spectroscopic investigations showed that the β-cyclodextrin–EoY conjugate retains both the fluorescence properties and the capability to photogenerate singlet oxygen of the unbound chromophore. In contrast, the corresponding β-cyclodextrin–EoB conjugate did not show either relevant emission or photosensitizing activity probably due to aggregation in aqueous medium, which precludes any response to light excitation.

Xanthene-stained nanoparticles for phosphorescence anisotropy measurements

“…For the novel measurement method to be easily applied, it would be convenient to have phosphorescent particles that could be used in an existing PIV setup with only minor modifications. Rhodamine B (RB) and other species of the xanthene group like Eosin Y (EY) and Erythrosine B (EB) exhibit phosphorescence at different levels of efficiency (Benkovics et al, 2017;Bowers & Porter, 1967;Eads et al, 1984;Parker & Hatchard, 1961). In the case of EY and EB, the heavy ions bromine and iodine enable a higher phosphorescent quantum yield compared to RB.…”

Exploring the Inclusion Complex of an Anticancer Drug with β-Cyclodextrin for Reducing Cytotoxicity Toward the Normal Human Cell Line by an Experimental and Computational Approach

“…Upon encapsulation of the drug molecule within the CD pocket, upfield chemical shifts were observed for both the guest and the CD protons. This is mainly due to mutual shielding between the drug molecule and β-CD, thus resulting in enclosure of the former by the electron density of β-CD. , β-CD has H-5 and H-3 hydrogen atoms inside the cavity, whereas the remaining H-4, H-2, and H-1 hydrogen atoms lie on the exterior side of the surface. Thus, H-5 is placed in the vicinity of the narrower rim, whereas H-3 lies near the wider rim (Figure S7).…”

In vitro and in vivo characterization of erythrosin B and derivatives against Zika virus

“…Commercially available isothiocyanate 15 was coupled with trityl-protected cysteamine to give the intermediate 16 , which was then converted into the final product 17 via acidic deprotection. The detailed synthetic procedures of these derivatives followed the reported protocols in literatures 42 , 43 , 44 , 45 . The structures and purities of all synthesized compounds were evaluated by 1 H and 13 C NMR and HPLC analysis, respectively.…”