Ascorbic acid and adriamycin toxicity

Article Abstract:

Adriamycin (ADR, or doxorubicin) is an antibiotic with potent antitumor activity. It has been used in combination with other drugs to treat patients with leukemia, lymphoma, thyroid cancer, breast cancer, ovarian cancer, lung cancer, and Hodgkin's disease. However, the clinical use of ADR is limited by its toxic effects on the heart, which can be fatal. Damage to the heart muscle following treatment with ADR is believed to be caused by the formation of free radicals (highly reactive atoms with an unpaired electron). These radicals oxidize tissues and cell membranes (lipid peroxidation), causing cell death. Several studies have reported that antioxidants (substances that inactivate free radicals) may be effective in protecting the heart muscle from ADR-related lipid peroxidation. Ascorbic acid (vitamin C) is a potent antioxidant that has been reported to prolong the survival time of patients with advanced, untreatable cancer. This study was performed to determine if ascorbic acid and two derivatives of ascorbic acid, 2-O-octadecylascorbic acid (CV-3611) and ascorbyl palmitate, could be used to protect the heart from the toxic effects of ADR. Ascorbic acid prolonged the survival time of mice with leukemia or Ehrlich ascites carcinoma following treatment with ADR. Ascorbyl palmitate, but not ascorbic acid, potentiated the antitumor activity of ADR in these mice. When healthy mice and guinea pigs were treated with ADR, all three forms of ascorbic acid prolonged the lives of the animals. Treatment with ADR increased the levels of lipid peroxide in mouse heart, and this effect was prevented by ascorbic acid. These results indicate that ascorbic acid can delay the toxic effects of ADR on the heart, and that the combined use of ADR and ascorbic acid (or the derivatives) may increase the effectiveness of ADR in the treatment of certain cancers. (Consumer Summary produced by Reliance Medical Information, Inc.)

Drug therapy, Cancer, Antioxidants, Antioxidants (Nutrients), Doxorubicin

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

Article Abstract:

Several studies have reported that ascorbic acid (vitamin C) may reduce the risk of developing certain types of cancer. It has been reported that patients with malignant disease have abnormally low levels of ascorbic acid stored in their body tissues and that adding ascorbic acid to the diet may be beneficial in treating patients with cancer. Although some studies have reported that sodium ascorbate (10 grams per day) increases the survival time of patients with advanced and untreatable tumors, other studies have not been able to confirm these findings. Many studies performed in mice have reported that ascorbic acid delays the appearance and reduces the size of tumors and prolongs survival time. In some of these studies, partially oxidized ascorbic acid was more effective than fresh ascorbic acid, and the antitumor activity was enhanced when cupric sulfate (a substance that oxidizes ascorbic acid) was added. These findings suggest that certain oxidation products of ascorbic acid may be responsible for the antitumor activity. When human mammary tumors were transplanted into mice that were fed water with ascorbic acid, tumor growth was inhibited. The amount of ascorbic acid used in this study ranged from 4 to 20 milligrams per day. When ascorbic acid was added to food, tumor growth was not inhibited unless cupric sulfate was present in the drinking water. In addition, injections of freshly prepared ascorbate did not inhibit tumor growth unless cupric sulfate was added to the solution. An isomer of ascorbic acid (D-isoascorbate) had similar antitumor activity, indicating that the antitumor activity of ascorbic acid is not related to its vitamin properties. The results of this study support the hypothesis that oxidation or degradation products of ascorbic acid inhibit tumor growth. (Consumer Summary produced by Reliance Medical Information, Inc.)

Prevention, Development and progression, Growth, Growth (Physiology), Breast tumors

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Interactions between ascorbic acid and the radiation of bone marrow, skin, and tumor

Article Abstract:

Radiation is used to treat certain types of cancer. However, radiation treatment destroys normal, healthy tissue as well as tumors. Several studies have reported that ascorbic acid (vitamin C) reduces the biological effects of radiation. However, other studies have produced contradictory results. To investigate this issue further, the ability of ascorbic acid to protect skin and bone marrow from the harmful effects of radiation was evaluated in mice. Fibrosarcomas (connective tissue tumors) were transplanted into male and female mice. The mice were given injections of high doses of ascorbic acid (4.5 grams per kilogram of body weight) 50 minutes prior to radiation treatment. The ascorbic acid did not interfere with the ability of the radiation treatments to kill the tumors, but it did reduce the amount of skin and bone marrow damage. When radiation is used to treat cancer patients, the amount of radiation used is limited by its effects on the spinal cord, brain, kidneys and lungs. These tissues respond differently to radiation than skin and bone marrow. Further studies are needed to determine if ascorbic acid protects the spinal cord, brain, kidneys and lungs from radiation damage before it can be recommended for cancer patients undergoing radiation treatment. (Consumer Summary produced by Reliance Medical Information, Inc.)

Skin, Radiotherapy, Radiation effects, Skin, Effect of radiation on the

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