Metabolism and Metabolites

Carotenoid Metabolism and Metabolites. A scheme has been proposed for the metabolism of /3-carotene by the stick insect Carausius morosus to give /3,/8-caroten-2-ol (20) and /3,/3-carotene-2,2 -diol (21) via intermediate 2-oxo-compounds such as (27). Feeding experiments have shown that in the goldfish lutein [ S, -carotene-3,3 -diol (150)] and zeaxanthin are converted into astaxanthin (60) whereas /8-carotene and canthaxanthin (130) are not. Further studies suggest that marine red fish such as sea bream cannot oxidize the 3- and 4-positions of the /8-ring. 

In the intestine of a freshwater fish, Sacchobranchus fossilis, /8-carotene was converted into retinoic acid (40) whereas 3,4-didehydroretinol (152) and 3-hydroxyretinol (153) were obtained from lutein. The breakdown of 

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RB Sund, F Lauterbach. 1-Naphthol metabolism and metabolite transport in the small and large intestine. Pharmacol Toxicol 60 262-268, 1987. 

Oral absorption is good. It is largely metabolized and metabolites are excreted in urine and bile. 

Haslam E (1993) Shikimic Acid Metabolism and Metabolites Wiley, New York... 

E. Haslam, Shikimic Add Metabolism and Metabolites, Wiley, New York, 1993. 

Leung et al. 1988). However, these studies are limited to the biotransformation of individual compounds. Since most metabolic pathways have been identified or can be predicted for the individual PAHs. it is now important to understand how these metabolic pathways are affected when the PAHs compete. The carcinogenic and toxic potential of PAHs is associated with their metabolites. Alterations in rates of metabolism and metabolite profiles may affect the toxic consequences of PAHs. 

Capsaicin and capsaicinoids may be involved in complex interactions in vivo related to carcinogenesis, cocarcinogenesis and anticarcinogenesis, which are a reflection, in part, of metabolism and metabolite activity. Capsaicin... 

LU Haslam. Shikimic Acid Metabolism and Metabolites, p. 238-245, Chichester Wiley 1993 J. Chromatogr. 661, 93-104 (1994) (synthesis) Kerkut Gilbert (eds.). Compre-... 

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