Design of the Complex between Manganese Porphyrins and Catalase−Poly(ethylene glycol) Conjugates for a New Antioxidant

Catalytic antioxidants for therapeutic medicine

In this Review, we focus on catalytic antioxidant study based on transition metal complexes, organoselenium compounds, supramolecules and protein scaffolds.

Poly(Ethylene glycol)-based backbones with high peptide loading capacities

Polymer-peptide conjugates are a promising class of compounds, where polymers can be used to overcome some of the limitations associated with peptides intended for therapeutic and/or diagnostic applications. Linear polymers such as poly(ethylene glycol) can be conjugated through terminal moieties and have therefore limited loading capacities. In this research, functionalised linear poly(ethylene glycol)s are utilised for peptide conjugation, to increase their potential loading capacities. These poly(ethylene glycol) derivatives are conjugated to peptide sequences containing representative side-chain functionalised amino acids, using different conjugation chemistries, including copper-catalysed azide-alkyne cycloaddition, amide coupling and thiol-ene reactions. Conjugation of a sequence containing the RGD motif to poly(allyl glycidyl ether) by the thiol-ene reaction, provided a conjugate which could be used in platelet adhesion studies.

Human serum albumin mutants complexed Mn(III) protoporphyrin IX as superoxide dismutase mimics

Genetically engineered human serum albumin (HSA) mutants complexed Mn(III) protoporphyrin IX (MnPP) in the haem pocket showed superoxide dismutase activity. Replacement of a proximal Tyr-161 by non-coordinating Leu caused a remarkable increase in enzyme activity.

Pharmaceutical effect of manganese porphyrins on manganese superoxide dismutase deficient mice

Mice lacking manganese-superoxide dismutase (Mn-SOD) activity exhibit typical pathology of dilated cardiomyopathy (DCM). In the present study, the structure-activity relationship between the water-soluble manganese (Mn) porphyrin with SOD activity and the in vivo pharmaceutical effect on DCM is reported. The Mn-SOD-deficient mice were treated with Mn-porphyrins for 3 weeks. The treatment of a Mn-porphyrin, MnM2Py(2)P, suppressed the progression of cardiac dilation. These results suggest that the Mn-porphyrin MnM2Py(2)P treatment is proposed as a potential therapy for DCM.

Highly amphiphilic manganese porphyrin for the mitochondrial targeting antioxidant

Here, we communicate that the design of the anti-oxidant consisting of amphiphilic manganese porphyrin with one dimethylimidazolium group and three phenyl groups for mitochondrion targeting. The resulting Mn-porphyrin MnMImP(3)P exhibited high partition coefficient (logP(ow) = +4.78) as well as significant superoxide dismutase and peroxynitrite decomposition activities. Accordingly, the MnMImP(3)P exhibited a little increase in fluorescence intensity attributed to 3,3'-dipropyl-2,2'-thiadicarbocyanine iodide [diS-C(3)-(5)], a tracer dye to assess the mitochondrial membrane potential, which suggested the interaction of the MnMImP(3)P, leading to the release of the fluorescence dye from the mitochondrial membrane, with the mitochondria. As a result, the MnMImP(3)P rescued the cell death under oxidative stress concerned with mitochondrial damage.

Protective effects of the complex between manganese porphyrins and catalase-poly(ethylene glycol) conjugates against hepatic ischemia/reperfusion injury in vivo

The complex between manganese (Mn) porphyrins and catalase-poly(ethylene glycol) (PEG) conjugates has been designed for the protective effect against hepatic ischemia/reperfusion injury in vivo. The resulting Mn-porphyrin/catalase-PEG complex with dual enzymatic activity of superoxide dismutase (SOD) and catalase enhanced the blood circulation. The spin reduction rate in the rats treated with the Mn-porphyrin/catalase-PEG complex was significantly higher than that in the untreated rats and almost equal to that in the sham group rats. Furthermore, the Mn-porphyrin/catalase-PEG complex significantly decreased the serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels. These results suggest that the Mn-porphyrin/catalase-PEG complex exhibited the antioxidative activity to protect hepatic ischemia/reperfusion injury in vivo.