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Cyanate causes depletion of ascorbate in organisms
I Koshiishi1, Y Mamura, T Imanari
1Faculty of Pharmaceutical Sciences, Chiba University, Inage, Japan.
Biochimica Et Biophysica Acta
|November 21, 1997
Summary
Cyanate causes oxidative stress by depleting ascorbate, a key antioxidant. This reaction disrupts the ascorbate-dehydroascorbate redox cycle, leading to cellular damage and organism toxicity.
Area of Science:
- Biochemistry
- Plant Science
- Toxicology
Background:
- The ascorbate-dehydroascorbate redox cycle is crucial for cellular protection against oxidants.
- Ascorbate (vitamin C) and its oxidized form, dehydroascorbate, are vital antioxidants.
- Understanding antioxidant cycles is key to comprehending cellular defense mechanisms.
Purpose of the Study:
- To investigate the novel reaction between dehydroascorbate and cyanate.
- To determine the effect of cyanate on the ascorbate-dehydroascorbate redox cycle.
- To elucidate the mechanism of cyanate toxicity in biological systems.
Main Methods:
- Studied the reaction kinetics of dehydroascorbate with cyanate at neutral pH and ambient temperature.
- Applied sodium cyanate solution to weed (Erigeron canadensis) leaves.
- Quantified ascorbate and dehydroascorbate levels in treated plant tissues.
- Observed visual changes in plant tissues post-treatment.
Main Results:
- A novel, irreversible reaction between dehydroascorbate and cyanate was identified.
- Cyanate treatment led to significant depletion of both ascorbate and dehydroascorbate in plant tissues.
- Treated weed leaves exhibited a color change from green to brown, indicating cellular damage.
- The ascorbate-dehydroascorbate redox cycle was disrupted by cyanate exposure.
Conclusions:
- Cyanate toxicity may stem from its ability to induce oxidative stress.
- The reaction with cyanate depletes essential antioxidants, compromising cellular defense.
- This finding provides a biochemical basis for cyanate's herbicidal and toxic effects.