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Helen L. Gensler - One of the best experts on this subject based on the ideXlab platform.
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Cumulative reduction of primary skin tumor growth in UV-irradiated mice by the combination of Retinyl Palmitate and canthaxanthin.
Cancer letters, 1990Co-Authors: Helen L. Gensler, M. Aickin, Y. M. PengAbstract:The effects of dietary supplementation with Retinyl Palmitate, canthaxanthin, or the combination of both, on photocarcinogenesis was determined in pigmented C3HHeN mice. The basal diet was the American Institute of Nutrition Diet 76A, to which was added 120 IU of Retinyl Palmitate per g diet, 1 % canthaxanthin, or the combination of both. Administration of the diets began 18 weeks before the first UVB radiation (280–320 nm) treatment and continued throughout the study. The UV source was a bank of 6 Westinghouse FS40 lamps which delivered to the mice a total dose of 9.9 × 105 J/m2, delivered over 24 weeks. These diets significantly reduced the tumor burden per mouse induced by UV irradiation, however they did not influence tumor incidence. The combination of Retinyl Palmitate plus canthaxanthin was more effective than either agent alone at reducing autochthonous tumor growth, a result which has not been previously reported.
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Enhanced resistance to an antigenic tumor in immunosuppressed mice by dietary Retinyl Palmitate plus canthaxanthin.
Cancer letters, 1990Co-Authors: Helen L. Gensler, K. HolladayAbstract:Abstract Retinoids and certain carotenoids, e.g., β- catotene and canthaxanthin, have been found to prevent photocarcinogenesis in mice and also to act as immunoenhancers. The hypothesis that retinoids and carotenoids inhibit photocarcinogenesis by preventing UV induction of immunosuppression predicts that mice treated with these agents before and during periods of UV radiation treatments should be as resistant as unirradiated mice to an antigenic UV-induced tumor. To test this prediction, mice were fed 120 IU of Retinyl Palmitate per gram of diet, and/or 1% canthaxanthin, before UV irradiation treatments began, and during the entire experiment. After 4.95 × 10 5 Jm −2 , delivered over 12 weeks, resistance of mice to antigenic UV-induced tumor implants (UV20) was studied. Dietary supplementation with Retinyl Palmitate plus canthaxanthin, but not with either agent alone at these doses, prevented the enhanced growth of UV20 in UV irradiated mice.
Ronald R. Eitenmiller - One of the best experts on this subject based on the ideXlab platform.
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Stability of Tocopherols and Retinyl Palmitate in Snack Extrudates
Journal of Food Science, 2001Co-Authors: K. Suknark, Jeung-hee Lee, Ronald R. Eitenmiller, Robert D. PhillipsAbstract:: Fish- and peanut-containing half-products were obtained by extruding and drying tocopherol- and Retinyl Palmitate-fortified mixtures of tapioca starch and minced fish or partially defatted peanut flour (PDPF 60:40, wet basis). Half-products were puffed by deep-fat frying. Vitamins were determined simultaneously at each step of snack production using a direct solvent extraction method. Extrusion significantly reduced the content of tocopherols and Retinyl Palmitate in both products. Reduction of Retinyl Palmitate in fish and peanut extrudates during snack production was 48% and 27%, respectively. Final products contained more tocopherol than intermediates because of the high tocopherol content in the frying oil and its uptake.
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Liquid chromatographic analysis of all-trans-Retinyl Palmitate, β-carotene, and vitamin E in fortified foods and the extraction of encapsulated and nonencapsulated Retinyl Palmitate.
Journal of agricultural and food chemistry, 2000Co-Authors: William O Landen, Ronald R. EitenmillerAbstract:A liquid chromatographic method is described for the analysis of natural vitamin E homologues, all-rac-α-tocopheryl acetate, Retinyl Palmitate (encapsulated and nonencapsulated), and β-carotene in ...
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Analysis of all-rac-alpha-tocopheryl acetate and Retinyl Palmitate in medical foods using a zero control reference material (ZRM) as a method development tool.
Journal of AOAC International, 1999Co-Authors: Ronald R. Eitenmiller, Austin R LongAbstract:A liquid chromatographic method is described for analysis of all- rac-alpha-tocopheryl acetate and Retinyl Palmitate in medical food. The vitamins are extracted in isopropyl alcohol and hexane-ethyl acetate without saponification and quantitated by normal-phase chromatography with fluorescence detection. All rac-alpha-tocopheryl acetate and Retinyl Palmitate are chromatographed isocratically with a mobile phase of 0.5% (v/v) and 0.125% (v/v) isopropyl alcohol in hexane, respectively. Recovery studies performed on a medical food zero control reference material (ZRM) fortified with the analytes averaged 99.7% (n = 25) for Retinyl Palmitate and 101% (n = 25) for all- rac-alpha-tocopheryl acetate. Coefficients of variation were 0.87-2.63% for Retinyl Palmitate and 1.42-3.20% for all-rac-alpha-tocopheryl acetate. The method provides a rapid, specific, and easily controlled assay for analysis of vitamin A and vitamin E in medical foods. Use of chlorinated solvents is avoided.
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Liquid Chromatographic Analysis of All-Rac-α-Tocopheryl Acetate, Tocopherols, and Retinyl Palmitate in SRM 1846
Journal of Liquid Chromatography & Related Technologies, 1997Co-Authors: G. W. Chase, Ronald R. Eitenmiller, Austin R LongAbstract:Abstract A liquid chromatographic method is described for the analysis of all-rac-α-tocopheryl acetate, tocopherols, and Retinyl Palmitate in the infant formula standard reference material 1846. The vitamins are extracted in isopropanol and hexane/ethyl acetate without saponification and quantitated by normal phase chromatography with fluorescence detection. Retinyl Palmitate, all-rac-α- tocopheryl acetate, and naturally occurring tocopherols are quantitated isocratically with a mobile phase of 0.5% isopropanol in hexane. The results were within the certified ranges for all-rac-α-tocopheryl acetate and Retinyl Palmitate. Recoveries averaged 97.5% for Retinyl Palmitate and 101% for all-rac-α- tocopheryl acetate (n = 20).
Regina Drabent - One of the best experts on this subject based on the ideXlab platform.
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Fluorescent Properties of Vitamin a Derivative, Retinyl Palmitate, in Binary Solvents with Aqueous Phase
Spectroscopy Letters, 1998Co-Authors: Krzysztof Bryl, Regina Drabent, Teresa OlszewskaAbstract:Abstract Fluorescence emission and fluorescence excitation spactra of Retinyl Palmitate molecules in binary water/p-dioxane and water/isopropyl alcohol solvents under different solvents polarities were studied. The binary solvents polarities were changed by changing the molar ratios of water to p-dioxane (or isopropyl alcohol). It was suggested that the observed changes of spectral properties were caused by the formation of different Retinyl Palmitate self- organised structures that were induced by environments of different polarity. The role of non (low) polar components of binary solvents in the process of resultant structures creation is also discussed.
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Retinyl Palmitate IN WATER ENVIRONMENT
Journal of Photochemistry and Photobiology B: Biology, 1997Co-Authors: Regina Drabent, Krzysztof Bryl, Bogdan Smyk, Krystyna UlbrychAbstract:Abstract The interaction between Retinyl Palmitate molecules and their environment in binary water- p -dioxane solvent (at different molar ratios of water to p -dioxane) was studied. The absorption, fluorescence emission and fluorescence excitation spectra were analysed. In this binary solvent, the interaction between Retinyl Palmitate molecules and environments of different polarity leads to the self-organization of Retinyl Palmitate. The possible consequences of the existence of self-organized structures for retinoid transport through the water phase are discussed.
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A Water Environment Forces Retinyl Palmitate to Create Self-Organized Structures in Binary Solvents
Journal of Fluorescence, 1997Co-Authors: Regina Drabent, Krzysztof Bryl, Teresa OlszewskaAbstract:The interaction between Retinyl Palmitate molecules and their environment in binary water/p-dioxane and water/isopropyl alcohol solvents was studied under different solvent polarities. The binary solvent polarities were changed by changing the molar ratios of water to p-dioxane (or isopropyl alcohol). The fluorescence emission and fluorescence excitation spectra were analyzed. In binary solvents, the interaction between Retinyl Palmitate molecules and environments of different polarities leads to the self-organization of Retinyl Palmitate, and as a result, different fluorescence centers are created. The similar fluorescence properties of these centers in different binary solvents were interpreted as a water driving force inducing the self-organization of Retinyl Palmitate. The possible consequences of this phenomenon for misleading interpretation of model studies of retinol interaction with retinol transporting proteins are also discussed.
Y. M. Peng - One of the best experts on this subject based on the ideXlab platform.
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Cumulative reduction of primary skin tumor growth in UV-irradiated mice by the combination of Retinyl Palmitate and canthaxanthin.
Cancer letters, 1990Co-Authors: Helen L. Gensler, M. Aickin, Y. M. PengAbstract:The effects of dietary supplementation with Retinyl Palmitate, canthaxanthin, or the combination of both, on photocarcinogenesis was determined in pigmented C3HHeN mice. The basal diet was the American Institute of Nutrition Diet 76A, to which was added 120 IU of Retinyl Palmitate per g diet, 1 % canthaxanthin, or the combination of both. Administration of the diets began 18 weeks before the first UVB radiation (280–320 nm) treatment and continued throughout the study. The UV source was a bank of 6 Westinghouse FS40 lamps which delivered to the mice a total dose of 9.9 × 105 J/m2, delivered over 24 weeks. These diets significantly reduced the tumor burden per mouse induced by UV irradiation, however they did not influence tumor incidence. The combination of Retinyl Palmitate plus canthaxanthin was more effective than either agent alone at reducing autochthonous tumor growth, a result which has not been previously reported.
Alejandro Catala - One of the best experts on this subject based on the ideXlab platform.
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The effect of alpha tocopherol, all-trans retinol and Retinyl Palmitate on the non enzymatic lipid peroxidation of rod outer segments.
Molecular and cellular biochemistry, 1999Co-Authors: Mario Guajardo, A Terrasa, Alejandro CatalaAbstract:The effect of a tocopherol, all-trans retinol and Retinyl Palmitate on the non enzymatic lipid peroxidation induced by ascorbate-Fe2+ of rod outer segment membranes isolated from bovine retina was examined. The inhibition of light emission (maximal induced chemiluminescence) by alpha tocopherol, all-trans retinol and Retinyl Palmitate was concentration dependent. All trans retinol showed a substantial degree of inhibition against ascorbate-Fe2+ induced lipid peroxidation in rod outer segment membranes that was 10 times higher than the observed in the presence of either at tocopherol or Retinyl Palmitate. Inhibition of lipid peroxidation of rod outer segment membranes by alpha tocopherol and Retinyl Palmitate was almost linear for up to 0,5 micromol vitamin/mg membrane protein, whereas all-trans retinol showed linearity up to 0,1 micromol vitamin/mg membrane protein. Incubation of rod outer segments with increasing amounts of low molecular weight cytosolic proteins carrying I-[14C] linoleic acid, [3H] Retinyl Palmitate or [3H] all-trans retinol during the lipid peroxidation process produced a net transfer of ligand from soluble protein to membranes. Linoleic acid was 4 times more effectively transferred to rod outer segment membranes than all-trans retinol or Retinyl Palmitate. Incubation of rod outer segments with delipidated low molecular weight cytosolic proteins produced inhibition of lipid peroxidation. The inhibitory effect was increased when the soluble retinal protein fraction containing alpha tocopherol was used. These data provide strong support for the role of all-trans retinol as the major retinal antioxidant and open the way for many fruitful studies on the interaction and precise roles of low molecular weight cytosolic retinal proteins involved in the binding of antioxidant hydrophobic compounds with rod outer segments.
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The effect of α tocopherol, all-trans retinol and Retinyl Palmitate on the non enzymatic lipid peroxidation of rod outer segments
Molecular and Cellular Biochemistry, 1999Co-Authors: Mario Guajardo, A Terrasa, Alejandro CatalaAbstract:The effect of α tocopherol, all-trans retinol and Retinyl Palmitate on the non enzymatic lipid peroxidation induced by ascorbate-Fe2+ of rod outer segment membranes isolated from bovine retina was examined. The inhibition of light emission (maximal induced chemiluminescence) by α tocopherol, all-trans retinol and Retinyl Palmitate was concentration dependent. All trans retinol showed a substantial degree of inhibition against ascorbate-Fe2+ induced lipid peroxidation in rod outer segment membranes that was 10 times higher than the observed in the presence of either α tocopherol or Retinyl Palmitate. Inhibition of lipid peroxidation of rod outer segment membranes by α tocopherol and Retinyl Palmitate was almost linear for up to 0,5 μmol vitamin/mg membrane protein, whereas all-trans retinol showed linearity up to 0,1 μmol vitamin/mg membrane protein. Incubation of rod outer segments with increasing amounts of low molecular weight cytosolic proteins carrying 1-[14C] linoleic acid, [3H] Retinyl Palmitate or [3H] all-trans retinol during the lipid peroxidation process produced a net transfer of ligand from soluble protein to membranes. Linoleic acid was 4 times more effectively transferred to rod outer segment membranes than all-trans retinol or Retinyl Palmitate. Incubation of rod outer segments with delipidated low molecular weight cytosolic proteins produced inhibition of lipid peroxidation. The inhibitory effect was increased when the soluble retinal protein fraction containing a tocopherol was used. These data provide strong support for the role of all-trans retinol as the major retinal antioxidant and open the way for many fruitful studies on the interaction and precise roles of low molecular weight cytosolic retinal proteins involved in the binding of antioxidant hydrophobic compounds with rod outer segments.
