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ARS Home » Northeast Area » Boston, Massachusetts » Jean Mayer Human Nutrition Research Center On Aging » Research » Publications at this Location » Publication #163977
Title: EFFECTS OF ALPHA-TOCOPHEROL AND ASCORBIC ACID ON THE PRODUCTION OF BETA-APO-CAROTENALS AND RETINOIDS FROM BETA-CAROTENE IN THE LUNG TISSUES OF CIGARETTE SMOKE-EXPOSED FERRETS IN VITRO

Author
item LIU, CHUN - TUFTS-HNRCA
item RUSSELL, ROBERT - TUFTS-HNRCA
item WANG, XIANG-DONG - TUFTS-HNRCA

Submitted to: Journal of Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/11/2003
Publication Date: 2/1/2004
Citation: LIU, C., RUSSELL, R.M., WANG, X. EFFECTS OF ALPHA-TOCOPHEROL AND ASCORBIC ACID ON THE PRODUCTION OF BETA-APO-CAROTENALS AND RETINOIDS FROM BETA-CAROTENE IN THE LUNG TISSUES OF CIGARETTE SMOKE-EXPOSED FERRETS IN VITRO. JOURNAL OF NUTRITION. 2004;134:426-430.

Interpretive Summary: Previously, we found that exposing ferrets to cigarette smoke enhanced oxidative excentric cleavage of beta-carotene. In the present study, we examined whether alpha-tocopherol, ascorbic acid, or both combined can prevent smoke-altered beta-carotene metabolism. We found that the smoke-enhanced production of individual beta-apo-carotenals was decreased when alpha-tocopherol and ascorbic acid were added together into the incubation mixture. alpha-Tocopherol alone had a modest effect. Ascorbic acid in the presence of alpha-tocopherol inhibited the production of beta-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 when both alpha-tocopherol and ascorbic acid were added into the incubation mixtures. In conclusion, these data indicate that alpha-tocopherol and ascorbic acid act synergistically in preventing the enhanced oxidative excentric cleavage of beta-carotene induced by smoking exposure, thereby facilitating the conversion of beta-carotene into RA and retinal.

Technical Abstract: Previously, we found that exposing ferrets to cigarette smoke enhanced oxidative excentric cleavage of beta-carotene. In the present study, we examined whether alpha-tocopherol, ascorbic acid, or both combined can prevent smoke-altered beta-carotene metabolism. In vitro incubation of beta-carotene with lung post-nuclear fractions from ferrets exposed to cigarette smoke was carried out in the absence or presence of alpha-tocopherol, ascorbic acid, or both vitamins. The oxidative cleavage metabolites of beta-carotene, beta-apo-carotenals (beta-apo-14', beta-apo-12', beta-apo-10', and beta-apo-8'), retinoic acid (RA), and retinal were analyzed by HPLC. We found that the smoke-enhanced production of individual beta-apo-carotenals was decreased by 36% to 75% when alpha-tocopherol (50 micro-mol/L) and ascorbic acid (50 micro-mol/L) were added together into the incubation mixture. Alpha-tocopherol alone had a modest effect. Ascorbic acid in the presence of alpha-tocopherol inhibited the production of beta-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 folds) when both alpha-tocopherol and ascorbic acid were added into the incubation mixtures. However, when ascorbic acid or alpha-tocopherol alone were added, the production of RA among smoke exposed ferrets was only modestly increased (~1.8 folds) and approached to the RA levels among control ferrets. In conclusion, these data indicate that alpha-tocopherol and ascorbic acid act synergistically in preventing the enhanced oxidative excentric cleavage of beta-carotene induced by smoking exposure, thereby facilitating the conversion of beta-carotene into RA and retinal.