Water-Soluble Mn(III)-Porphyrins with High Relaxivity and Photosensitization
Tamás Németh, Agnès Pallier, Çetin Çelik, Zoltán Garda, Naoko Yoshizawa-Sugata, Hisao Masai, Éva Tóth, Yoko Yamakoshi
Abstract
High Resolution Image Download MS PowerPoint Slide Three water-soluble Mn(III)-porphyrin complexes with cationic pyridyl side groups bearing COOH- or OH-terminated carbon chains in the meta or para positions have been synthesized as probes for both magnetic resonance imaging (MRI) and photodynamic therapy (PDT). The complexes Mn-1, Mn-2, and Mn-3 are highly water-soluble, and their relaxivities range between 10 and 15 mM –1 s –1, at 20–80 MHz and 298 K, 2–3 times higher than that of commercial Gd(III)-based agents. The complexes containing carboxylate ( Mn-2 ) or alcoholic ( Mn-3 ) side chains in the para position are endowed with higher relaxivities and have also shown efficient photoinduced DNA cleavage and singlet oxygen ( 1 O 2 ) generation. Mn-3 with stronger photoinduced DNA cleavage has also revealed stabilizing and binding activities for G4 DNA, at a similar level as the known G4 binder Mn-TMPyP4 . Nevertheless, the G4-binding activity of Mn-3 was nonspecific. Preliminary tests evidenced photocytotoxicity of Mn-3 on HeLa cells without a significant effect in the absence of light. Altogether, these results underline the potential of such water-soluble Mn(III)-porphyrins for the development of multimodal approaches combining MRI and PDT.