Trans lycopene

J w, Jr. (1996) Cis-trans lycopene isomers, carotenoids and retinol in the human prostate. Cancer Epidemiol Biomarkers Prev. 5(10) 823-33. 

Kucuk, O. et al.. Effects of lycopene supplementation in patients with localized prostate cancer, Exp. Biol. Med. (Maywood), 227, 881, 2002. van Breemen, R.B. et al.. Liquid chromatography-mass spectrometry of cis- and all-trans-lycopene in human serum and prostate tissue after dietary supplementation with tomato sauce, J. Agric. Food Chem., 50, 2214, 2002. 

AW-trans lycopene X-carotene y-carotene All-trans lycopene p-carotene p-cryptoxanthin a-carotene... 

All-trans P-carotene, 15-cis-lycopene, all-trans y-carotene, 13-cis-lycopene, 9-cis-lycopene, all-trans-lycopene + 5-cis-lycopene... 

A dry, thin lycopene layer heated at 50°C, 100°C, and 150°C showed first-order kinetic decay (Lee and Chen 2002). At 50°C, isomerization dominated in the first 9h however, degradation was favored afterward. On the other hand, at 100°C and 150°C degradation proceeded faster than isomerization. Although cis isomer identification was not confirmed by standards, the mono-civ lycopene isomers, 5-cis-, 9-cis-, 13-cis-, and 15-m-, degraded at the same rate as did all-trans-lycopene,... 

A second enzyme, BC02, was identified that cleaves carotenoids asymmetrically at the 9,10-double bond to produce the 10-apocarotenal (C27) and (3-ionone (C13), in a reaction similar to the Arabidopsis CCD7. Examples of BC02 have been cloned from mouse, zebra fish, ferret, and human (Kiefer et al. 2001, von Lintig et al. 2005, Hu et al. 2006). Substrate studies with different BC02s showed that these enzymes prefer acyclic carotenoids such as lycopene over cyclic carotenoids (Kiefer et al. 2001, von Lintig et al. 2005, Hu et al. 2006). These enzymes also seem to be selective for different carotenoid isomers. BC02 from ferret for example cleaves d,v-isomers of lycopene but not all-trans-lycopene (Hu et al. 2006). 

Boileau, A. C., N. R. Merchen, K. Wasson, C. A. Atkinson, and J. W. Erdman, Jr. 1999. Cis-lycopene is more bioavailable than trans-lycopene in vitro and in vivo in lymph-cannulated ferrets. J Nutr 129(6) 1176—1181. 

All-trans lycopene is rapidly isomerized to an equilibrium mixture with its cis isomers both in cell culture medium (Liu et al. 2006) and in vivo in prostate tissue (Clinton et al. 1996, van Breemen et al. 2002). The cis isomers of lycopene are absorbed better than the all -trans isomers when fed to humans (Unlu et al. 2007). The 5 -cis isomer predominates in plasma (Gustin et al. 2004). Since lycopene absorption by prostate cells might be due to facilitated diffusion (Liu et al. 2006), it is likely that the cis isomers of lycopene form a significant proportion of intracellular lycopene in the experiments that are reviewed later. 

An elegant study of lycopene uptake in LNCaP, PC-3, and DU-145 cells using beadlet-delivered 1.48 J.M all-trans lycopene (a maximal level in human plasma) found that all three cell lines rapidly took up lycopene during the first 10 h of incubation. Cells continued to accrue lycopene, but more slowly, over the next 48h. The uptake by the LNCaP cells was 2.5-fold higher than PC-3 cells and 4.5-fold higher than DU-145 cells at 24h of incubation but lycopene showed no affinity for the AR receptor, which is expressed in the LNCaP cells (Liu et al. 2006). LNCaP uptake followed Michaelis-Menten kinetics with a V m i, of 66.3pmol/106 cells/h and a Km of 7.72 pM lycopene. Because of the sensitivity of their LC-MS-MS lycopene assay, Liu et al. were also able to investigate the subcellular lycopene distribution. The nuclear membrane contained 55%, the nuclear matrix 26%, and the microsomal fraction 19% of the intracellular fraction. The cytosol contained no lycopene(Liu et al. 2006). 

Gomez-Prieto MS, Caja MM, Herraiz M and Santa-Maria G. 2003. Supercritical fluid extraction of all trans-lycopene from tomato. J Agric Food Chem 51(1 ) 3—7. 

Fig. 2.12. HPLC of the extract at 40°C and 4 000 psi with the entrainer. The identified components are in the order first peak (retention time 2.60min) = reference second peak (retention time 22.69min) = trans-lycopene third peak (retention time 25.22min = /(-carotene. Reprinted with permission from E. Cadoni et al. [36].

Fig. 2.24. C30 chromatograms of carotenoids extracted from human serum (a) xanthophylls fraction, 7 93 (v/v) MTBE-methanol mobile phase (b) a- and / -carotenes fraction, 11 89 (v/v) MTBE-methanol mobile phase (c) lycopene fraction, 38 62 (v/v) MTBE-methanol mobile phase. Tentative peak identifications (a) 1, 13-c/s-lu- lutein 2, 13 r/.vlutein 3, a//-/ra s-lutein 4, zeaan-thin 5-7, unidentified P,e-carotenoids and 8, / -cyrptoanthin (b) 1-2, unidentified ae-carotene isomers 3, 15-eH -/f-carotenc 4, 13-cw-/ -carotene 5, all-trans-a-carotene 6, all-trans-P-carotene and 7, 9-ci.v-/3-carotene and (c) 1-11 and 13, c/s-lycopene isomers and 12, all-trans-lycopene. Reprinted with permission from C. Emenhiser el al. [51].

FIG. 5 Cis and trans lycopene isomers in rat serum and tissues. Values expressed are mean SEM, n = 3. 

IMS is a relatively new technique in which ions are separated based on size and shape using an electric field. IMS was utilized by Dong et ah (2010) to separate all-trans -lycopene from cw-lycopene and all-irans -(3-carotene from cw-(3-carotene. Unfortunately, the various cis isomers could not be separated from each other using IMS alone. The authors provided evidence to suggest that cis/trans isomerization of carotenoids occur in-source (ESI positive mode was used in these experiments). Because of this isomerization, it does not appear likely that IMS will replace HPLC as a means of separating geometrical isomers of carotenoids in the near future (Dong et ah, 2010). 

Clinton, S.K., Emenhiser, C., Schwartz, S.J., Bostwick, D.G., Williams, A.W., Moore, B.J. and Erdman, J.W. 1996. Cis-trans lycopene isomers, carotenoids, and retinol in the human prostate. Cancer Epidemiol., Biomarkers Prevent., 5 823-833. 

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