Peroxidase-thiocyanate-peroxide antibacterial system does not damage DNA

Area of Science:

• Biochemistry
• Microbiology
• Genotoxicology

Background:

• Hypothiocyanite ion (OSCN(-)) is present in human saliva and acts as an oxidizing agent.
• Elevated OSCN(-) levels can inhibit oral bacteria, suggesting potential for enhanced salivary antibacterial properties.
• Concerns exist regarding potential DNA damage and oral mucosa effects from high OSCN(-) concentrations.

Purpose of the Study:

• To assess the genotoxic effects of high hypothiocyanite ion (OSCN(-)) concentrations.
• To evaluate the safety of elevated OSCN(-) levels on bacterial and yeast strains.
• To determine the in vitro reactivity of OSCN(-) with DNA.

Main Methods:

• Mutagenicity testing using Salmonella typhimurium strains sensitive to base-pair substitutions and frameshift mutations.
• Assessing effects on Saccharomyces cerevisiae for gene conversion, mitotic crossing-over, and reverse mutation.
• UV spectroscopy to analyze in vitro reactions between calf thymus DNA and OSCN(-).

Main Results:

• OSCN(-) exhibited toxicity to Salmonella typhimurium strains above 10 muM, with greater impact on strains with lipopolysaccharide defects.
• No mutagenic effects were observed in tested Salmonella typhimurium strains.
• Saccharomyces cerevisiae showed no adverse effects even at concentrations exceeding 800 muM.
• In vitro studies indicated no oxidation of calf thymus DNA by OSCN(-).

Conclusions:

• Elevated hypothiocyanite ion (OSCN(-)) concentrations, while toxic to certain bacteria, do not pose a genotoxic risk to host tissues.
• The findings support the potential use of supplements to enhance salivary antibacterial effects without compromising genetic material safety.