The effect of ascorbic acid on sodium nitrite-induced methemoglobin formation in glucose-6-phosphate dehydrogenase-deficient erythrocytes.

Ascorbic acid significantly reduced the occurrence of sodium nitrite-induced methemoglobin (METHB) formation in a dose-dependent manner in erythrocytes from glucose-6-phosphate dehydrogenase (G-6-PD)-deficient humans in vitro. The ascorbic acid treatment, however, also decreased levels of reduced GSH in a dose-dependent manner, a response indicative of oxidant stress to the erythrocyte membrane. The latter findings are inconsistent with the hypothesis that ascorbic acid supplementation in G-6-PD-deficient humans may help compensate for inherently low levels of erythrocyte GSH. Finally, the ascorbic acid-induced reduction of METHB values, while of statistical significance, does not appear to be of clinical significance.