Glycosylated zinc(II) phthalocyanines as efficient photosensitisers for photodynamic therapy. Synthesis, photophysical properties and in vitro photodynamic activity

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journal

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Author(s)

  • Chi-Fung Choi
  • Jian-Dong Huang
  • Pui-Chi Lo
  • Wing-Ping Fong
  • Dennis K. P. Ng

Detail(s)

Original languageEnglish
Pages (from-to)2173-2183
Journal / PublicationOrganic and Biomolecular Chemistry
Volume6
Issue number12
Publication statusPublished - 2008
Externally publishedYes

Abstract

Treatment of 3- or 4-nitrophthalonitrile with 1,2:5,6-di-O-isopropylidene- α-d-glucofuranose or 1,2:3,4-di-O-isopropylidene-α-d-galactopyranose in the presence of K2CO3 gave the corresponding glycosubstituted phthalonitriles. These precursors underwent self-cyclisation, or mixed-cyclisation with the unsubstituted phthalonitrile, to afford the tetra- or mono-glycosylated zinc(ii) phthalocyanines, respectively. As shown by absorption spectroscopy, these compounds were not significantly aggregated in organic solvents, giving a weak to moderate fluorescence emission. Upon irradiation these compounds could sensitise the formation of singlet oxygen in DMF, with quantum yields in the range of 0.40-0.66. The in vitro photodynamic activities of these compounds against HepG2 human hepatocarcinoma and HT29 human colon adenocarcinoma cells were also studied. The mono-glycosylated phthalocyanines exhibited significantly higher photocytotoxicity compared with the tetra-α-glycosylated analogues, having IC50 values down to 0.9 μM. The tetra-β-glycosylated counterparts were essentially inactive. The lower photocytotoxicities of the tetra-glycosylated phthalocyanines are in line with their lower cellular uptake and/or higher aggregation tendency as reflected by weaker intracellular fluorescence, and lower efficiency at generating intracellular reactive oxygen species. For the mono-glycosylated phthalocyanines, the higher uptake can be attributed to their hydrophilic saccharide units, which increase the amphiphilicity of the macrocycles. © The Royal Society of Chemistry 2008.

Citation Format(s)

Glycosylated zinc(II) phthalocyanines as efficient photosensitisers for photodynamic therapy. Synthesis, photophysical properties and in vitro photodynamic activity. / Choi, Chi-Fung; Huang, Jian-Dong; Lo, Pui-Chi; Fong, Wing-Ping; Ng, Dennis K. P.

In: Organic and Biomolecular Chemistry, Vol. 6, No. 12, 2008, p. 2173-2183.

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journal