The selective lignin-degrading fungus, Ceriporiopsis subvermispora secretes alkylitaconic acids (ceriporic acids) during wood decay. We reported that ceriporic acid B (hexadecylitaconic acid) was protective against the depolymerization of cellulose by the Fenton reaction. To understand the redox silencing effects, we analyzed the physicochemical and redox properties of itaconic, octylitaconic and hexadecylitaconic acids. The initial rate of HO center dot production by the Fenton system with Fe3+, H2O2 and L-cysteine was suppressed by hexadecylitaconic and octylitaconic acids by 0.04 and 0.16 of the reaction rate without chelators. ESR, O-2 uptake and the assay of Fe2+ with BPS demonstrated that Fe3+ reduction by L-cysteine was suppressed by hexadecylitaconic and octylitaconic acids while the reaction of Fe2+ with H2O2 was not suppressed by the two alkylitaconic acids. Ligand exchange experiments with NTA demonstrated that Fe3+ chelation by two carboxyl groups of alkylitaconic acids is a critical step in iron redox modulation. In stark contrast, the production of HO center dot and reduction of Fe3+ were not suppressed by itaconic acid due to HO center dot-initiated degradation of the chelator. The strong redox silencing effects by a series of alkylitaconic acids have attracted interest in controlling microbial plant cell wall degradation and chemoprotection against cellular oxidative injury.