Inhibiting effect of ascorbic acid on the growth of human mammary tumor xenografts

Abstract

The effect of ascorbic acid on the growth of a human mammary tumor in mice has been investigated using the 6-d subrenal capsule assay method. The results indicated that ascorbic acid administered in the drinking water significantly inhibited the growth of the tumor fragments implanted beneath the renal capsule of mice. Administration of a mixture of ascorbic acid and cupric sulfate orally or intraperitoneally significantly inhibited tumor growth in these mice, whereas neither alone was effective. These results support the hypothesis that certain oxidation or degradation products of ascorbic acid were active antineoplastic agents for the human mammary tumor studied. The activity of D-isoascorbic acid, an isomer of ascorbic acid, was similar to that of ascorbic acid. This suggests that the antitumor activity of ascorbic acid was not due to the metabolism of ascorbic acid as a vitamin, but due to its chemical properties.

Modulation of N-methyl-N-nitrosourea induced mammary tumors in Sprague–Dawley rats by combination of lysine, proline, arginine, ascorbic acid and green tea extract

“…Ascorbic acid has been shown to have growth inhibitory and antineoplastic activities in human mammary tumor bearing mice [12]. In addition, low levels of ascorbic acid have been reported in cancer patients [13-15].…”

Vitamin C in human health and disease is still a mystery? An overview

“…A mixture of ascorbic acid and cupric sulfate significantly inhibited human mammary tumor growth in mice, while administered orally [67]. Ascorbic acid decreased the incidence of kidney tumors by estradiol or diethylstilbesterol in hamsters due to decrease in the formation of genotoxic metabolites viz., diethylstilbesterol-4'-4"-qunione [68].…”

Orthomolecular Oncology Review: Ascorbic Acid and Cancer 25 Years Later

“…[34][35][36][37][38] Nevertheless, all reports are in accord that this cytotoxic effect produced by ascorbate in an array of cell lines (mostly malignant) has been associated with its prooxidant activity. 23,[39][40][41][42][43][44][45] Ascorbate and its radical potentiate the activation of transcription factor NF-κB, which has been associated with inhibition of cell growth. 46 The Role of Hydrogen Peroxide Ascorbate can generate hydrogen peroxide (a reactive oxygen species) on oxidation (with oxygen) in biological systems.…”

“…[28][29][30][31][32][33][34][50][51][52]63,[70][71][72][73] As mentioned previously, the antiproliferative action of ascorbate in malignant cultured cells, animal, and human tumor xenografts has been augmented by the addition of the cupric ion, a catalyst for the oxidation of ascorbate. 34,[39][40][41][74][75][76] In addition, the combination of ascorbate and copper has been shown to inactivate lactate dehydrogenase, 77 the enzyme responsible for the reduction of pyruvate to lactate (a metabolic dead-end product prevalent in anaerobic environments such as in cancer). Copper in the form of copper sulfate may also inhibit tyrosinase activity.…”

“…[92][93][94][95] Other AA Oxidation Products AA oxidation products such as dehydroascorbic acid, 2,3-diketogulonic acid, and 5-methyl 1-3, 4-dehydroxytetrone, all degradation products of AA, have demonstrated antitumor activity. 34,[39][40][41][42] In addition, other compounds arising from the oxidation or degradation of ascorbate can inhibit tumor growth. The most effective ones are γ-cronolactone and 3-hydroxy-2-pyrone.…”