Vitamin inhibitory effect

In contrast to heparin, the coumarinic acid anticoagulants are inactive in vitw ]6k.e heparin they are active in vivo. The phenylindanedione-type compounds (7) (36) and warfarin (2) produce their in vivo inhibitory effect on the coagulation system by competitively antagonizing the normal activity of vitamin (8) (37—44). 

Moreno FS, S-Wu T, Naves MM, Silveira ER, Oloris SC, Costa MA, Dagli ML and Ong TP. 2002. Inhibitory effects of beta-carotene and vitamin A during progression phase of hepatocarcinogenesis involve inhibition of cell proliferation but not alterations in DNA methylation. Nutr Cancer 44 80-... 

Sampaio ARD, Chagas CEA, Ong TP and Moreno FS. 2007. Vitamin A and 3-carotene inhibitory effect during 1,2-dimethylhydrazine induced hepatocarcinogenesis potentiated by 5-azacytidine. Food Chem... 

Olas and Wachowicz (2002) investigated the effects of tranx-resveratrol and vitamin C on oxidative stress in blood platelets. The level of 02 in control blood platelets and platelets incubated with resveratrol or vitamin C was recorded using a chemiluminescence method. On the other hand, Oh and others (2006) reported the x02 quenching activities of various freshly squeezed fruit and vegetable juices by measuring their inhibitory effects on the rubrene oxidation induced by x02 from disproportionation of hydrogen peroxide by sodium molybdate in a microemulsion system. 

Studies on competitive inhibition of Bi2 activity show that certain substituted benzimidazoles, purines, and pteridines have weak inhibitory effects in bacterial systems (SlOa). Substituted amides of Bi2 (S9) inhibited the growth-promoting effects of vitamin B12 in protozoic and bacterial systems (B5, B6). The anilide of B12 shows a definite inhibitory effect on maturation and proliferation of blood-forming cells of the chick embryo an opposite effect is induced by vitamin Bi2 (E2). 

Takagi, A., Sai, K., Umemura, T., Hasegawa, R. Kurokawa, Y. (1995) Inhibitory effects of vitamin E and ellagic acid on 8-hydroxydeoxyguanosine formation in liver nuclear DNA of rats treated with 2-nitropropane. Cancer Lett., 91, 139-144... 

We had previously eliminated the possibility that retinol affected bacterial viability in this assay. The likelihood of a non-specific inhibitory effect of retinol was also eliminated, since there was no effect of vitamin A alcohol on mutagenicity induced by adriamycin, a direct-acting mutagen in Salmonella (23). Thus, these findings demonstrated that retinol inhibited the metabolism of 2-fluorenamine by rat liver tissue preparations to forms capable of producing mutations in S typhimurium. 

D7. Doscherholmen, A., McMahon, J., and Ridley, D., Inhibitory effects of eggs on vitamin BI2 absorption Description of a simple ovalbumin Co-vitamin B12 absorption test. Br. ]. Haematol. 33, 261-272 (1976). 

Several terpenoids have been evaluated for their inhibitory effects on EBV-EA activation induced by TPA. Table 6 shows the inhibitory effects of monoterpenoids [70,71], sesquiterpenoids [20,119-123], diterpenoids [21,123-131], and meroterpenoids [117] against TPA (32 pmol, 20 ng)-induced EBV-EA activation in Raji cells. The inhibitory effects were compared with that of [3-carotene, a vitamin A precursor that has been studied intensively in cancer chemoprevention using animal models [2,4]. All of the terpenoids tested caused higher viability (60-80%) of Raji cells even at mol ratio of compound to TPA = 1000 1 indicating their very low cytotoxicity at that high concentration (refer to Table 6). 

However, this reaction cannot possibly account for the inhibitory effect of sulfite. It is thought that sulfur dioxide reacts with the degradation products of the amino sugars, thus preventing these compounds from condensing into melanoidins. A serious drawback of the use of sulfur dioxide is that it reacts with thiamine and proteins, thereby reducing the nutritional value of foods. Sulfur dioxide destroys thiamine and is therefore not permitted for use in foods containing this vitamin. 

The degradation rate of vitamin A palmitate under UV radiation was significantly lower in the presence of mixtures of amino acids (85). Tween 80 provides a good inhibitory effect on chloramphenicol photolysis due to incorporation of the drug within the micelles (86). 

An increased incidence of infection, even sepsis after intramuscular injection, as an adverse effect of megadose vitamin E therapy in very low birth weight infants was first reported in Japan in 1986 (SEDA-12, 330). In a review of the literature in 1992 it was concluded that pharmacological serum concentrations of vitamin E might predispose premature infants to infectious complications, possibly caused by an inhibitory effect of vitamin E on the formation of superoxide anion in leukocytes (27). 

In more recent times, large doses of vitamin C have been claimed to prevent the common cold, cure infertility, delay the onset of symptoms in AIDS, and inhibit the development of gastric and cervical cancers. Proof is still lacking for most of these claims, but a recent study in Europe did find statistical evidence for an inhibitory effect against gastric cancers. Although large daily doses of vitamin C are probably not warranted, the harmful side effects of vitamin C appear minimal, and many people have adopted a better safe than sorry approach. 

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