Water-soluble cyclodextrin (CyD)-complexed with porphyrin derivatives with different substituents in the mesopositions showed different photodynamic activities toward cancer cells under illumination at wavelengths over 600 nm, the most suitable wavelengths for photodynamic therapy (PDT). In particular, aniline- and phenol-substituted derivatives had high photodynamic activity because of the efficient intracellular uptake of the complexes by tumor cells. These complexes showed greater photodynamic activity than photofrin, currently the main drug in clinical use as a photosensitizer. These results represent a significant step towards the optimization of porphyrin derivatives as photosensitizers.

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Experimental procedures and UV-vis absorption and NMR spectra (PDF).

This work was supported by JSPS KAKENHI Grant-in-Aid for Scientific Research (B) (Grant No. JP16H04133) and Grant-in-Aid for Challenging Exploratory Research (Grant No. JP16K13982) and the Electric Technology Research Foundation of Chugoku.