10.1039/a900190e
Ralf Schmid, Friederike Goebel, André Warnecke, and Andreas Labahn study on the synthesis and redox potential measurements of various methylated vitamin K derivatives. The study aims to systematically vary the redox potentials of vitamin K derivatives by introducing different numbers of methyl groups in various positions to investigate their role in electron transfer reactions and structure-function relationships in vitamin K-dependent enzymes. The authors synthesized a range of vitamin K3, K1, and K2 derivatives with varying methyl substitutions and measured their redox potentials using cyclic voltammetry in DMF. They found that increasing the number of methyl substituents generally decreased the reduction potentials due to the electron-donating effect of alkyl groups. The study provides a wide range of reduction potentials for these derivatives, which are relevant for understanding electron transfer in photosynthetic reaction centers and for studying the binding affinity and steric properties of these compounds in biological systems.
10.1039/c2ob25229e
The research focuses on the exploration of the trifluoromenadione core as a template for designing antimalarial redox-active agents that interact with glutathione reductase. The study involves the synthesis, electrochemical analysis, enzyme kinetics, and antimalarial activities of a series of 1,4-naphthoquinone derivatives, specifically focusing on their reactivity under quasi-physiological conditions in NADPH-dependent glutathione reductase reactions. The experiments utilized various reactants, including menadione, its fluoro-analogues, and atovaquone derivatives, and employed techniques such as cyclic voltammetry, enzyme assays involving human and Plasmodium falciparum glutathione reductases, mass spectrometry, and in vitro parasite cultures for assessing antiparasitic and cytotoxic effects. The analyses encompassed the determination of IC50 values, redox potentials, enzyme inhibition properties, and the chemical stability of the synthesized compounds. The research aimed to develop multitarget-directed drugs by combining the trifluoromenadione core with the alkyl chain of the antimalarial drug atovaquone, revealing a mechanism for the CF3 group as a leaving group and demonstrating potent antimalarial activity against malarial parasites in culture.
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