Comparative study of the anti-HIV activities of ascorbate and thiol-containing reducing agents in chronically HIV-infected cells

Article Abstract:

Several studies have reported that ascorbic acid (vitamin C) can inactivate poliovirus, herpesvirus, vaccinia virus, and hepatitis virus. Other studies have found that ascorbic acid can prevent the intracellular replication of rhinovirus, Rous sarcoma virus and human T cell leukemia virus. Some studies have indicated that vitamin C can improve the conditions of patients with poliomyelitis, hepatitis and infectious mononucleosis. Twenty different studies have reported that vitamin C can protect against the common cold and reduce the severity of cold symptoms. In a recent study, ascorbic acid was shown to inhibit the activity and growth of the AIDS virus, also known as human immunodeficiency virus or HIV. Several reports have described clinical improvement in patients with AIDS after they took large doses of vitamin C. This study was performed to determine if ascorbic acid can inhibit the growth of HIV. This virus attacks and destroys white blood cells called T lymphocytes. When T lymphocytes infected with HIV were grown in culture, ascorbic acid inhibited the growth of the virus by inhibiting the activity of an enzyme called reverse transcriptase (an enzyme that makes DNA). When ascorbic acid was removed from the culture, HIV began to replicate again. Ascorbic acid is an antioxidant that protects cells from damage caused by oxidation. Two other antioxidants (thiol-containing reducing agents), N-acetyl-Cysteine (NAC) and glutathione (GSH), were tested for their ability to inhibit the growth of HIV in infected T lymphocytes. NAC inhibited HIV replication, but GSH had no effect. Although NAC was not as effective as ascorbic acid, the greatest effect was observed when NAC and ascorbic acid were used together. These results indicate that ascorbic acid has antiviral activity against HIV and may be of therapeutic value in controlling HIV replication in infected patients. Approximately 12 grams of vitamin C would have the be taken to equal the dose of ascorbic acid used in these experiments. Intravenous infusion would be the best way to deliver such a high dose of vitamin C. (Consumer Summary produced by Reliance Medical Information, Inc.)

HIV (Viruses), HIV

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An open trial of high-dosage antioxidants in early Parkinson's disease

Article Abstract:

Parkinson's disease is characterized by tremor, muscular rigidity and weakness, and an abnormal gait. This disease usually begins in individuals over 50 years old and progresses with time. The brain pathology in Parkinson's disease involves a loss of certain neurons leading to reduction of dopamine (a neurotransmitter) levels. Conventional therapy involves treatment with the drug levodopa to increase brain dopamine levels. During the neuronal damage and loss occurring in Parkinson's disease, catecholamines may be oxidized, resulting in the production of oxygen radicals (highly reactive atoms with unpaired electrons). These oxygen radicals cause further tissue damage and destruction. Antioxidant vitamins, such as vitamin E (tocopherol) and vitamin C (ascorbic acid), can protect tissues from damage caused by oxygen radicals. Tocopherol and ascorbic acid were administered to 15 patients showing early symptoms of Parkinson's disease to determine if antioxidants may slow the development of Parkinson's disease. In this preliminary study, the antioxidant vitamins delayed the requirement for treatment with levodopa by 2.5 years as compared with another group of patients (in another study) who were not taking antioxidant vitamins. It must be noted, however, that the second group was not an equivalent control group, and may not be comparable in some ways to the vitamin-treated group. It is concluded that antioxidants may be beneficial in Parkinson's disease, but that a placebo-controlled, double-blind study needs to be performed to evaluate these results further. (Consumer Summary produced by Reliance Medical Information, Inc.)

Evaluation, Vitamin therapy, Parkinsonism

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Scientific basis for medical therapy of cataracts by antioxidants

Article Abstract:

A cataract is a film that forms over the lens of the eye, thereby reducing the transparency of the lens and limiting vision. In the elderly, cataracts are the most common form of visual impairment. Several factors that may contribute to the formation of cataracts have been identified; they include the duration and intensity of exposure to sunlight, oxygen radicals (highly reactive atoms with unpaired electrons), tryptophan and vitamin B-2 deficiency, diabetes, and hypoparathyroidism. Oxygen in the air may be an important factor in the development of cataracts since oxygen inside the eye can be converted to highly reactive and damaging oxygen radicals. Superoxide dismutase is an enzyme present in the eye that removes oxygen radicals. Antioxidant vitamins such as vitamin E, vitamin C and beta-carotene can protect tissues from damage caused by oxygen radicals and thus may be effective in preventing cataracts. In animal studies, treatment with vitamin E, vitamin C and beta-carotene reduced cataract formation. Further studies are needed to determine if antioxidant vitamins will provide an effective therapy for cataracts in humans. (Consumer Summary produced by Reliance Medical Information, Inc.)

Usage, Risk factors, Cataract, Cataracts, Beta carotene

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