Cellular and microbial macromolecules modified by free iodine

Cellular and microbial macromolecules modified by free iodine represent the collective pharmacological targets of iodine-based antiseptics and disinfectants. Free iodine (I2) is a highly reactive oxidizing agent that rapidly penetrates the cell walls of bacteria, fungi, viruses, and protozoa. Once inside the cell, it targets a wide array of biological molecules, including proteins, nucleotides, and fatty acids. Specifically, iodine reacts with the sulfhydryl groups of cysteine and methionine, the phenolic groups of tyrosine, and the nitrogen atoms of histidine and nucleic acids (Gottardi, 1991). This non-specific interaction causes the denaturation of vital enzymes and structural proteins, effectively halting microbial metabolism and replication. Additionally, the iodination of unsaturated fatty acids disrupts the integrity of the cell membrane, leading to lysis. Because iodine attacks multiple essential cellular components simultaneously, it possesses a broad spectrum of activity and a very low risk of inducing antimicrobial resistance (Cooper, 2007). In clinical practice, iodine is typically delivered via carriers like povidone to provide a sustained release of free iodine, which balances potent biocidal activity with reduced toxicity to host tissues.

Other names

Microbial proteins and lipidsIodinated macromoleculesTargets of povidone-iodineIodine-modified cellular componentsIodinated microbial proteins

Free iodine (I2) acts as a potent oxidizing agent that penetrates microbial cell walls and membranes to iodinate and oxidize key amino acids (such as cysteine, tyrosine, and histidine) and unsaturated fatty acids. This process leads to the rapid denaturation of essential enzymes and structural proteins, as well as the disruption of cell membrane integrity, resulting in microbial cell death (McDonnell & Russell, 1999; Bigliardi et al., 2017).