Synthesis of Water-Soluble Dinuclear Mn-Porphyrin with Multiple Antioxidative Activities

Abstract

Superoxide dismutase (SOD) and catalase activities of a drug are of great importance for its effective protection against reactive oxygen species (ROS)-induced injury. Achievement of catalase activity of a synthetic compound remains a challenge. Water-soluble Mn-porphyrins have high SOD and peroxynitrite (ONOO(-)) reducing activities, but not catalase-like activity. Herein, we are able to retain the fair SOD-like activity of a mononuclear Mn-5-(N-methylpyridinium-4-yl)-10,15,20-triphenyl porphyrin (MnM4PyP3P), while gaining in catalase-like activity with its dinuclear complex, 1,3-di[5-(N-methylene-pyridinium-4-yl)-10,15,20-triphenyl porphynato manganese] benzene tetrachloride (MnPD). Mechanistic study indicates that catalase-like activity of MnPD is due to synergism of two Mn active sites, where hydroxo-Mn(IV) complex is formed as an intermediate. The in vivo experiments demonstrate that MnPD significantly restores the treadmill-running ability of SOD-deficient mouse and thus indicates the therapeutic potential of MnPD. Furthermore, MnPD may serve as a mechanistic tool and indicate the new directions in the synthesis of catalase-like mimics.

Selective Formation of a Mixed‐Valence State from Linearly Bridged Oligo(aromatic diamines): Drastic Structural Change into a Folded Columnar Stack for Half‐filled Polycations

“…Its redox properties are similar to those of p ‐ IV [ 22] with a p ‐xylylene‐α,α′‐diyl ( p ‐ XY ) spacer, in which two BIC units are too far apart to interact. After a systematic examination of several other spacers (Figure S3 in the Supporting Information), the hitherto uncommon meta ‐xylene‐α,α′‐diyl ( m ‐ XY ) spacer was found to be quite suitable for pimer formation as evident from the redox properties of m ‐ IV . In addition, m ‐ IV is reluctant to form a π‐dimer in solution.…”

“…However,i tw as provent hat o-XY is ineffectivea s the corresponding BIC dimer (o-IV) [14] does not adopt af olded geometry to form ap imer.I ts redox properties are similart o those of p-IV [22] with a p-xylylene-a,a'-diyl (p-XY)s pacer, in which two BIC units are too far apart to interact. After as ystematice xamination of severalo ther spacers ( Figure S3 in the Supporting Information), the hitherto uncommon [24,25] metaxylene-a,a'-diyl (m-XY)s pacerw as found to be quite suitable for pimer formation as evident from the redox properties of m-IV. [14] In addition, m-IV is reluctant to form a p-dimeri ns olu- tion.…”

Mechanistic studies on versatile metal-assisted hydrogen peroxide activation processes for biomedical and environmental incentives

“…Manganese 5-(N-methylpyridinium-4-yl)-10,15, 20-triphenyl porphyrin is a complex capable of both O2 •− dismutation and ONOO − reduction, whereas its dimer efficiently mimics catalase activity. The difference in the activity results from the synergism of two metal centers and the ability to create Mn IV -OH as oxidizing intermediate [160].…”

Dinuclear Cu(II) complexes based on p‐xylylene‐bridged bis(1,4,7‐triazacyclononane) ligands: Synthesis, characterization, DNA cleavage abilities and evaluation of superoxide dismutase‐ and catalase‐like activities

“…This result hints that rigid or semi‐rigid spacers should be introduced into the bis‐tacn (or multi‐tacn) ligands to facilitate the formation of dinuclear (or polynuclear) metal compounds. Since SOD mimics usually produce toxic hydrogen peroxide during the catalytic cycles by a ping‐pong mechanism, the mimicking compounds exhibiting both SOD‐ and catalase‐like activities are intensively pursued which demonstrate special advantage over those merely having SOD activity . Therefore, there is a growing requirement to develop small molecular mimics showing dual SOD/catalase activity to be used as antioxidant drugs.…”