Lycopene isomers

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

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,... 

Similar results were obtained during hot-break processing of tomato juice and even of tomato paste, the amounts of trans- and cis- lycopene isomers remained almost unchanged, whereas increased levels of ris-P-carotene were found during these processes (Abushita et al. 2000). 

Presence of Lycopene Isomers and Oxidation Products in Culture Media.442... 

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].

EFFECT OF HEATING TOMATO JUICE IN THE PRESENCE OF LIPIDS ON LYCOPENE ISOMERS... 

Configurational stability of lycopene isomers established at two levels of ab initio computation... 

Antioxidant properties of lycopene isomers as indicated by their ionization potential... 

FIG. 3 Stability and antioxidant properties of lycopene isomers (Chasse et al.9 2001). 

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

Tomato Lycopene isomers, P-carotene SFE C-30 MeOH-H20- MTBE HPLC/PAD (285, 347, 450 nm) 40... 

Tomato, human prostate Lycopene isomers, a/p-carotene Tomato extraction with acetone-hexane Prostate protein precipitation, extraction with acetone-hexane C-30 MeOH-MTBE- ammonium acetate HPLC/ECD 50 fmol for lycopene 34... 

Human plasma Lycopene isomers, a/p/y-carotene Extraction with hexane, centrifugation, saponification with KOH C-18/C-30 ACN-MTBE HPLC/MS/MS/ APCI(+/-) 11.2 fmol for lycopene 32... 

Human serum, prostate Lycopene isomers, a/p-carotene Saponification with KOH, extraction with hexane, centrifugation C-30 MeOH-MTBE HPLC/PDA (450 nm)/MS/ APCI(+) 0.93 pmol for lycopene 109... 

Fang L, Pajkovic N, Wang Y, Gu C and van Breemen RB, Quantitative analysis of lycopene isomers in human plasma using high-performance liquid chromatography-tandem mass spectrometry. Anal Chem 75 812-817 (2003). 

A C30 column can be used to distinguish between all-trans -lutein and all-tra 5-zeaxanthin and their cis isomers (Updike and Schwartz, 2003), P-carotene and P-carotene cis isomers (Emenhiser et al., 1995), and lycopene and cA-lycopene isomers (Frohlich et al., 2007). C30 columns can allow the separation of isomers induced by heat processing (Figure 4.4) and induced in vivo (Figure 4.5). Extensive reviews on... 

Figure 4.5 Representative HPLC chromatogram of (a) tomato product lycopene isomers in (b) plasma lyeopene isomers from healthy individuals consuming different lyeopene-containing tomato products for 15 days, demonstrating the presence of isomers in human blood plasma versus the -trans form found in most foods (Hadley et al., 2003).

Allen, C.M. Schwartz, S.J. Craft, N.E. Giovannucci, E.L. De Groff, V.L. Clinton, S.K. 2003. Changes in plasma and oral mucosal lycopene isomer concentrations in healthy adults consuming standard servings of processed tomato products. Nutr. Cancer 47 48-56. 

Lycopene Isomers in Various Commercial Tomato Products... 

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. 

Z-isomers con tribute up to about 50% of total plasma lycopene content [16, 20]. Schierle et al. [8] and others [26] found the 5-Z-isomer to be the next most abundant form after all-E-lycopene (Fig. 3). It should be noted that some analytical methods are unable to resolve the 5-Z- and all-E-lycopene isomers because of congruency in the UV/ Vis spectra (e.g., from photo-diode array detection) used for identification (Fig. 3, insert). 13-Z-, 15-Z-, and 9-Z-Lycopene isomers are also detectable in human plasma at low concentrations, typically less than 5% of the all-E compound. 

Figure 3 Pattern of lycopene isomers in a human blood sample. (Insert) Photo-diode array detection spectra of all-E-lycopene and 5-Z-lycopene. (From Ref. 8.)...

Upon exposure to thermal energy, absorption of light, or involvement in specific chemical reactions, interconversion of lycopene isomers is known to take place. The cis isomers of lycopene, formed by rotation around any of its conjugated double bonds, have chemical and physical characteristics distinctly different from their all-frans counterparts. Some of the differences resulting from trans-to-cis isomerization include lower melting point, decreased color intensity, a shift in the lambda max, smaller extinction coefficients, and the appearance of a new maximum in the ultraviolet spectrum. ... 

C/5-isomers preferentially accumulate in tissnes, and all dietary carotenoids that are present in human seram may be accnmnlated in prostate. Lycopene and other major carotenoids have been shown to be present in higher concentrations in malignant prostate tissue relative to normal prostate tissue, although no apparent difference in the lycopene isomer ratio existed between benign and malignant tissnes S -trans lycopene 12 to 21% and cis isomers 79 to 88% of total lycopene). A hypothesis to explain this is that since the metabolism of the prostate is regulated by the neuroendocrine axis and uptake of... 

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