Studies on mitochondria directed plastoquinones

Abstract

Mitochondria-targeted cationic plastoquinone derivatives (SkQs, e.g. SkQ1, SkQR1) and their analogs lacking plastoquinol moiety (C12TPP, C12R1) can pass through bilayer phospholipid membrane. Their cationic forms are accumulated in isolated mitochondria or in mitochondria of living cells, driven by membrane potential. These compounds were extensively tested in model lipid membranes, isolated mitochondria and in living human cells in culture. It was found that SkQs are antioxidants that quench reactive oxygen species (ROS) in mitochondria, and mild uncouplers that facilitate transmembrane proton transport by fatty acids. Both properties result in efficient prevention of oxidative stress and protection of mitochondria and cells from damage by ROS, making SkQs a promising drug candidate against pathologies caused by excess mitochondrial ROS generation. Recent discovery of SkQ1 antibacterial activity at concentrations not toxic to human cells opens a perspective for development of new antibiotics. In this chapter, we summarize recent in vitro experiments with mitochondria-targeted plastoquinones.