Bromine biological roles

Bromine is thought to be essential for plants and animals, although no known biological role has been established. It has flame-extinguishing characteristics and is used in fireproofing agents and to make flame-resistant plastics. 

Bromine exists as the molecule Br2, with no biological role in humans. 

The above discussions clearly demonstrates the importance of 6-pyrrole brominated porphyrins in both fundamental and applied fields of porphyrin chemistry. While one aim of these studies has been to gain insights into the role of macrocycle distortion in relation to biological systems containing porphyrins or related macrocycles , another has been to determine which factors influence the robustness of such catalysts in the oxidation of organic substrates ". Both measurements of electrochemical redox potentials and spectral properties of the porphyrins are needed to understand these properties and both are reviewed in this chapter on yS-pyrrole brominated porphyrins. 

It has been reported that a dietary deficiency of bromide results in depression of growth, fertility, hematocrit, hemoglobin, and life expectancy, and increases in milk fat and spontaneous abortions in goats. Other biological actions that suggest bromine could possibly act in an essential role include the findings that bromide alleviates growth retardation caused by hyperthyroidism in mice and chicks, and insomnia exhibited by many hemodialysis patients has been associated with bromide deficit. 

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