Indicadores
The orally bioavailable alpha form of the naturally-occurring fat-soluble vitamin E, with potent antioxidant and cytoprotective activities. Upon administration, alpha-tocopherol neutralizes free radicals, thereby protecting tissues and organs from oxidative damage. Alpha-tocopherol gets incorporated into biological membranes, prevents protein oxidation and inhibits lipid peroxidation, thereby maintaining cell membrane integrity and protecting the cell against damage. In addition, alpha-tocopherol inhibits the activity of protein kinase C (PKC) and PKC-mediated pathways. Alpha-tocopherol also modulates the expression of various genes, plays a key role in neurological function, inhibits platelet aggregation and enhances vasodilation. Compared with other forms of tocopherol, alpha-tocopherol is the most biologically active form and is the form that is preferentially absorbed and retained in the body.
Indicadores
Hexahydro-2-oxo-1H-thieno(3,4-d)imidazole-4-pentanoic acid. Growth factor present in minute amounts in every living cell. It occurs mainly bound to proteins or polypeptides and is abundant in liver, kidney, pancreas, yeast, and milk. The biotin content of cancerous tissue is higher than that of normal tissue.
Indicadores
A collective term for pteroylglutamic acids and their oligoglutamic acid conjugates. As a natural water-soluble substance, folic acid is involved in carbon transfer reactions of amino acid metabolism, in addition to purine and pyrimidine synthesis, and is essential for hematopoiesis and red blood cell production. (NCI05)
Indicadores
An antimetabolite and antifolate agent with antineoplastic and immunosuppressant activities. Methotrexate binds to and inhibits the enzyme dihydrofolate reductase, resulting in inhibition of purine nucleotide and thymidylate synthesis and, subsequently, inhibition of DNA and RNA syntheses. Methotrexate also exhibits potent immunosuppressant activity although the mechanism(s) of actions is unclear.
Indicadores
A water-soluble vitamin ubiquitously found in plants and animal tissues with antioxidant property. Vitamin B5 is a component of coenzyme A (CoA) and a part of the vitamin B2 complex. Vitamin B5 is a growth factor and is essential for various metabolic functions, including the metabolism of carbohydrates, proteins, and fatty acids. This vitamin is also involved in the synthesis of cholesterol, lipids, neurotransmitters, steroid hormones, and hemoglobin.
Indicadores
A long-acting barbituric acid derivative with antipsychotic property. Phenobarbital binds to and activates the gamma-aminobutyric acid (GABA)-A receptor, thereby mimicking the inhibitory actions of GABA in the brain. The activation effects of the phenobarbital-receptor-ionophore complex include increased frequency of chloride channel openings, membrane hyperpolarization and ultimately synaptic inhibition and decreased neuronal excitability. In addition, this agent inhibits glutamate induced depolarization.
Indicadores
A hydantoin derivative and a non-sedative antiepileptic agent with anticonvulsant activity. Phenytoin potentially acts by promoting sodium efflux from neurons located in the motor cortex reducing post-tetanic potentiation at synapses. The reduction of potentiation prevents cortical seizure foci spreading to adjacent areas, stabilizing the threshold against hyperexcitability. In addition, this agent appears to reduce sensitivity of muscle spindles to stretch causing muscle relaxation.
Indicadores
The fat soluble vitamin retinol. Vitamin A binds to and activates retinoid receptors (RARs), thereby inducing cell differentiation and apoptosis of some cancer cell types and inhibiting carcinogenesis. Vitamin A plays an essential role in many physiologic processes, including proper functioning of the retina, growth and differentiation of target tissues, proper functioning of the reproductive organs, and modulation of immune function.
Indicadores
A natural alkaloid derivative of xanthine isolated from the plants Camellia sinensis and Coffea arabica. Theophylline appears to inhibit phosphodiesterase and prostaglandin production, regulate calcium flux and intracellular calcium distribution, and antagonize adenosine. Physiologically, this agent relaxes bronchial smooth muscle, produces vasodilation (except in cerebral vessels), stimulates the CNS, stimulates cardiac muscle, induces diuresis, and increases gastric acid secretion; it may also suppress inflammation and improve contractility of the diaphragm. (NCI04)
Indicadores
A heat-labile and water-soluble essential vitamin, belonging to the vitamin B family, with antioxidant, erythropoietic, mood modulating, and glucose-regulating activities. Thiamine reacts with adenosine triphosphate (ATP) to form an active coenzyme, thiamine pyrophosphate. Thiamine pyrophosphate is necessary for the actions of pyruvate dehydrogenase and alpha-ketoglutarate in carbohydrate metabolism and for the actions of transketolase, an enzyme that plays an important role in the pentose phosphate pathway. Thiamine plays a key role in intracellular glucose metabolism and may inhibit the action of glucose and insulin on arterial smooth muscle cell proliferation. Thiamine may also protect against lead toxicity by inhibiting lead-induced lipid peroxidation.
