Nutrient Interactions and Toxicity alpha-Tocopherol and Ascorbic Acid Decrease the Production of ß-Apo-carotenals and Increase the Formation of Retinoids from ß-Carotene in the Lung Tissues of Cigarette Smoke–Exposed Ferrets In Vitro1 Chun Liu, Robert M. Russell and Xiang-Dong Wang2 Nutrition and Cancer Biology Laboratory, Jean Mayer U.S. Department of Agriculture Human Nutrition Research Center on Aging at Tufts University, Boston, MA 02111 2To whom correspondence should be addressed. E-mail: xiang-dong.wang@Tufts.edu. Previously, we found that exposing ferrets to cigarette smoke enhanced oxidative excentric cleavage of ß-carotene. In the present study, we examined whether alpha-tocopherol, ascorbic acid, or the two combined can prevent smoke-altered ß-carotene metabolism. In vitro incubation of ß-carotene (10 µmol/L) with lung postnuclear fractions from ferrets exposed to cigarette smoke was carried out in the absence or presence of -tocopherol (50 µmol/L), ascorbic acid (10 or 50 µmol/L), or both vitamins to evaluate their effects on the production of ß-apo-carotenals and retinoids from ß-carotene. The oxidative cleavage metabolites of ß-carotene, ß-apo-carotenals (ß-apo-14', ß-apo-12', ß-apo-10', and ß-apo-8'), retinoic acid (RA), and retinal were analyzed by HPLC. We found that the smoke-enhanced production of individual ß-apo-carotenals was significantly decreased by 36–77% when -tocopherol (50 µmol/L) and ascorbic acid (50 µmol/L) were added together to the incubation mixture. alpha-Tocopherol alone had a modest effect. Ascorbic acid in the presence of alpha-tocopherol inhibited the production of ß-apo-carotenals in a dose-dependent manner, although ascorbic acid alone had no effect. In contrast, the production of RA and retinal among smoke-exposed ferrets was substantially increased (3-fold, P < 0.05) when both alpha-tocopherol and ascorbic acid were added to the incubation mixtures. However, when ascorbic acid or alpha-tocopherol alone was added, the production of RA among smoke-exposed ferrets increased only modestly (80%, P < 0.05) and did not differ from the RA levels in control ferrets. In conclusion, these data indicate that alpha-tocopherol and ascorbic acid may act synergistically in preventing the enhanced oxidative excentric cleavage of ß-carotene induced by smoking exposure, thereby facilitating the conversion of ß-carotene into RA and retinal. J. Nutr. 134:426-430, February 2004 Remember we are NOT Doctors and have NO medical training. This site is like an Encylopedia - there are many pages, many links on many topics. Support our work with any size DONATION - see left side of any page - for how to donate. You can help raise awareness of CAM.