The effectiveness of a mixture of β‐carotene, α‐tocopherol, glutathione, and ascorbic acid for cancer prevention

Abstract

Previous studies have shown that β‐carotene and α‐tocopherol can act synergistically to inhibit the growth of experimentally induced oral cancer. The initial studies on the synergistic anticancer activity of antioxidants have been extended to include reduced glutathione and ascorbic acid.

Sixty male hamsters (4–5 wks old) were divided into six equal groups. Groups 1–6 were treated with 7,12‐dimethylbenz[a]anthracene (DMBA) (0.5% solution). Group 2 received a mixture containing equal amounts of β‐carotene, dl‐α‐tocopherol (vitamin E), glutathione, and l‐ascorbic acid (vitamin C) (12.5 μg) delivered orally by pipette. Groups 3–6 were treated with β‐carotene alone (50 μg), vitamin E alone (50 μg), glutathione (50 μg) alone, and vitamin C alone (50 μg). Animals were euthanized at 12 and 14 weeks. Tumors were counted and measured, and tumor burden was calculated for each experimental group. The mixture of antioxidants significantly reduced tumor burden, whereas the β‐carotene, vitamin E, and reduced glutathione treatments also reduced tumor burden. β‐Carotene and glutathione provided greater levels of chemoprevention than vitamin E as single agents. In contrast, vitamin C treatment produced no antitumor effect but increased tumor burden by Week 14. This mixture of antioxidants produced a significant synergistic chemoprevention of oral cancer.