| Abstract
| - A first report on the synthesis and biological evaluation of the β-galactose-conjugated purpurinimides(a class of chlorins containing a six-membered fused imide ring system) as Gal-1 (galectin-1)recognized photosensitizers, prepared from purpurin-N-propargylimide via enyne metathesis, isdiscussed. On the basis of examination of the available crystal structure of the galectin-1N-acetyllactose amine complex, it was considered that the chlorin-based photosensitizers could beintroduced into a carbohydrate skeleton to expand the repertoire of the galectin-1-specific ligands.Preliminary molecular modeling analysis utilizing the modeled photosensitizers and the availablecrystal structures of galectin−carbohydrate complexes indicated that addition of the photosensitizerto the carbohydrate moiety at an appropriate position does not interfere with the galectin-carbohydrate recognition. Under similar drug and light doses, compared to the free purpurinimideanalogue, the purpurinimides conjugated either with galactose or with lactose (Gal(β1−4)-Glc)produced a considerable increase in photosensitizing efficacy in vitro. This indicates the possibilityfor development of a new class of specific photosensitizers for photodynamic therapy (PDT) basedon recognition of a cellular receptor.
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