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A series of silicon(IV) phthalocyanines substituted axially with different polyamine moieties have been prepared. Their fluorescence quantum yields (ΦF= 0.03−0.08) in N,N-dimethylformamide are low because of reductive quenching by the amino moieties. The values are significantly increased in aqueous media (ΦF= 0.12−0.21) as a result of protonation of the amino substituents. All the compounds are highly photocytotoxic against human colon adenocarcinoma HT29 cells and Chinese hamster ovary cells with IC50values as low as 1.1 nM. Flow cytometric studies of two selected compounds (2and 5) against HT29 cells have shown that they induce apoptosis extensively. As shown by confocal microscopy, these two compounds also show high affinity toward the lysosomes, but not the mitochondria, of the cells. Their in vivo photodynamic activity has also been investigated using HT29 tumor bearing nude mice. Both of them can effectively inhibit the growth of the tumor without causing apparent injury to the liver of the mice. [ABSTRACT FROM AUTHOR]

A new series of di-α-substituted zinc(II) phthalocyanine derivatives have been prepared by mixed cyclisation of the corresponding 1,4-disubstituted phthalonitriles or naphthalonitriles with an excess of unsubstituted phthalonitrile in the presence of Zn(OAc)2.2H2O and 1,8-diazabicyclo[5.4.0]undec-7-ene. Having a large hydrophobic macrocyclic core substituted with two hydrophilic triethylene glycol chains or glycerol moieties, these compounds are amphiphilic in nature. They are highly soluble and remain non-aggregated in DMF as shown by the intense and sharp Q-band absorption. Compared with the unsubstituted zinc(II) phthalocyanine, these di-α-substituted analogues exhibit a red-shifted Q band (at 689-701 nm), a relatively weaker fluorescence emission, and a higher efficiency to generate singlet oxygen. Upon illumination, these compounds are highly cytotoxic towards HT29 human colorectal carcinoma and HepG2 human hepatocarcinoma cells with IC50 values as low as 0.06 mM. The high photocytotoxicity of these compounds can be attributed to their high cellular uptake and low aggregation tendency in the biological media, leading to a high efficiency to generate reactive oxygen species inside the cells. [ABSTRACT FROM AUTHOR]