Iron and its complexation by phenolic cellular metabolites

Abstract

Iron is a transition metal that forms chelates and complexes with various organic compounds, also with phenolic plant secondary metabolites. The ligands of iron affect the redox potential of iron. Electrons may be transferred either to hydroxyl radicals, hydrogen peroxide or molecular oxygen. In the first case, oxidative stress is decreased, in the latter two cases, oxidative stress is increased. This milieu-dependent mode of action may explain the non-linear mode of action of juglone and other secondary metabolites. Attention to this phenomenon may help to explain idiosyncratic and often nonlinear effects that result in biological assays. Current chemical assays are discussed that help to explore these aspects of redox chemistry.

The cytoskeleton is disrupted by the bacterial effector HrpZ, but not by the bacterial PAMP flg22, in tobacco BY-2 cells

“…Cell divisions in tobacco suspension cells are synchronized by signals that depend on polar auxin transport which can be monitored as frequency peak of cells composed of six cells (Campanoni et al ., 2003). Since polar auxin transport is strongly dependent on actin organization (reviewed in Nick, 2010), the division synchrony can be used as highly sensitive marker for actin remodelling and had been used successfully to monitor cell-death-related actin bundling (Chang et al ., 2011). In response to flg22, the amplitude of this peak increased progressively up to 3-fold as compared to the control (Supplementary Fig.…”

Exploration of pro-oxidant and antioxidant activities of the flavonoid myricetin

“…Flavonoids also slow the Fenton reaction by chelating iron ions, which affects the redox potentials of both the ligand and the central atom. [20][21][22][23] Iron-flavonoid complexes are more efficient antioxidant agents than the free flavonoids. 22 Myricetin-iron(II) complexes have been shown to be stable and to compare with the well-known chelation agent desferoxamine at a neutral pH.…”

Pro- and Antioxidant Activity of Three Selected Flavan Type Flavonoids: Catechin, Eriodictyol and Taxifolin

“…Its redox activity is especially interesting in the context of various biological effects [16,17,18,19]. Bais et al formulated a hypothesis about the phytotoxicity of catechin that is exuded by the roots of Centaurea stoebe , an invasive spotted knapweed in North America [20].…”