YOU ARE NOW CONNECTED TO THE TOXLINE (1981 FORWARD, NON-ROYALTY) FILE. ==ANTIOXIDANT VITAMINS== 2 AUTHOR Diplock AT TITLE Safety of antioxidant vitamins and beta-carotene. SOURCE Am J Clin Nutr 1995 Dec;62(6 Suppl):1510S-1516S ABSTRACT Epidemiologic evidence links high antioxidant status with low risk of degenerative disease. Optimal intakes of antioxidants may not be achievable by diet alone; supplements may be taken, particularly in subgroups of the population at high risk. It is thus necessary to ensure that antioxidant supplements are safe and free from side effects. The toxicity of vitamin E is low; no mutagenic, teratogenic, or carcinogenic effects are known and in double-blind studies in which large amounts of vitamin E were used in humans, no side effects occurred. High concentrations are contraindicated in subjects with vitamin K-associated blood coagulation disorders, and the toxicity in normal subjects ingesting large amounts of vitamin E over long periods requires additional investigation. Toxicity of beta-carotene also is low. Evidence from human toxicity trials is not available but there is much circumstantial evidence that 15-50 mg/d is without side effects except for hypercarotenemia in some subjects at high intakes. The findings of more lung cancer in subjects who smoked and who were given 20 mg beta-carotene/d than in those given a placebo could be influenced by the cancer being well advanced before beta-carotene administration. Massive anecdotal evidence exists that vitamin C (at > or = 1 g/d) is safe. Exhaustive literature searches have failed to reveal a controlled study of vitamin C toxicity in human subjects. Anxiety exists about oxalate stone formation, uricosuria, vitamin B-12 destruction, mutagenicity, and iron overload, but the consensus is that adverse effects do not occur in healthy subjects ingesting large amounts of vitamin C. 5 AUTHOR Vasarhelyi B AUTHOR Blazovics A AUTHOR Feher J TITLE [The role of vitamin A analogues and derivatives in the regulation of cell function] SOURCE Orv Hetil 1993 Apr 18;134(16):845-8 ABSTRACT The vitamin A and the retinoids, the vitamin A derivatives play an important role in the embryogenesis, in the modulation of the growth, in the differentiation of normal, premalignant and malignant epithelial and mesenchymal cells and in the maintenance of immune response. The effects of vitamin A are executed by two different mechanisms. While the carotenoids of provitamin A activity and the vitamin A--the retinol--itself are mainly antioxidant molecules and so some of their effects are partly similar to the effects of tocopherol, the retinoids, the derivatives of vitamin A, exert their diverse effects by regulating the expression of specific genes by the aid of specific nuclear receptors belonging to the family of steroid, thyroid hormone, and vitamin D3 receptors. The retinoids play a role in the modulation of the effect of these hormones as well. 6 AUTHOR Coppi G TITLE [Dihydroergocristine. A review of pharmacology and toxicology] SOURCE Arzneimittelforschung 1992 Nov;42(11A):1381-90 ABSTRACT A pharmacological and toxicological review of dihydroergocristine (DHEC, CAS 17479-19-5) is reported. Dihydroergocristine exercises a double agonistic/antagonistic activity on dopaminergic and adrenergic receptors; it also shows a non competitive antagonistic effect on serotonin receptors. The central effects of DHEC depend on the initial cerebrovascular resistance. DHEC exercises an inhibiting effect on the anaerobic glycolysis and on aerobic oxidation processes. It increases the cerebral blood flow and the oxygen consumption of the brain. Dihydroergocristine protects the brain against the metabolic effects of ischaemia by acting at a cellular level. In age-related modifications of the cerebral enzymatic antioxidant system DHEC increases the reduced glutathione. DHEC exercises a vasoregulating amphoteric action which depends on the initial tonus: it is hypotensive in hypertensive and normotensive animals but it is hypertensive in hypotensive animals. The results of acute and chronic toxicity in rats, dogs and monkeys, of teratogenesis and fertility in rats and rabbits and of mutagenic tests show that DHEC is a non toxic and well tolerated drug. 6 AUTHOR Sen CK TITLE Oxygen toxicity and antioxidants: state of the art. SOURCE Indian J Physiol Pharmacol; VOL 39, ISS 3, 1995, P177-96 (REF: 91) ABSTRACT Although the use of oxygen as metabolic fuel allows an attractive harvest of energy rich phosphates per molecule of glucose, a significant fraction of oxygen utilized by the body incompletely reduced and is known to be toxic. Such partially reduced forms of oxygen and some of their derivatives are highly reactive pro-oxidants that are collectively referred to as reactive oxygen species (ROS). A multitude of factors are known to modulate the amount of ROS formation in the body. To escape ROS dependent toxicity biological structures have their protective machinery in the form of physiological antioxidants. It appears that the physiological antioxidants are not independently capable of completely detoxifying the ROS constantly produced by the body. The supply of exogenous antioxidants is thus crucial. Endo- and exogenous antioxidants act in concert to minimize ROS dependent damage. ROS are involved in the pathogenesis of a large number of clinical disorders. The sensitive balance between the pro- and anti- oxidant forces in the body appears to be very crucial in determining the state of health, well being and longevity. This article presents an introductory overview covering the current concepts related to oxidants and antioxidants with special reference to human health.