Lycopene
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| Surname | Lycopene | ||||||||||||||||||
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| Molecular formula | C 40 H 56 | ||||||||||||||||||
| Brief description |
dark red needles |
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| Molar mass | 536.85 g mol −1 | ||||||||||||||||||
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firmly |
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172-173 ° C |
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| As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions . | |||||||||||||||||||
Lycopene , also lycopene or leukopene, belongs to the class of carotenoids and is found in high concentrations in tomatoes - from whose scientific name Solanum lycopersicum the name of the substance derives - and rose hips . The substance belongs to the tetraterpenes and has a red color due to its polyene structure , which also gives the tomatoes their characteristic color. It is approved as food coloring E 160d in the EU . Lycopene is one of the antioxidants and is considered a radical scavenger , i. that is, it can render certain reactive molecules harmless in the human body.
properties
Lycopene is a linear, acyclic polyene and one of the unsaturated carotenoids. It has 13 double bonds , 11 of which are conjugated . Methyl groups are at positions 1, 5, 9, 13 and mirrored at 1 ', 5', 9 'and 13'. The many conjugated double bonds give lycopene a ruby red color. The absorption maximum in hexane is 472 nm. Because of its strongly hydrophobic character, lycopene is almost insoluble in water, ethanol or methanol, but is good in chloroform , benzene , hexane, acetone or other organic solvents.
Lycopene is sensitive to light, heat, oxygen and acids. Metal ions such as Cu (II) or Fe (III) catalyze its oxidation.
meaning
Lycopene is one of the most widespread natural red pigments and is only synthesized by plants, fungi and microorganisms. In plants, it absorbs light with other carotenoids for photosynthesis and protects chlorophyll molecules from oxidative damage caused by light and oxygen.
In green vegetables or in (green) leaves, the natural color of lycopene is masked by green pigments (e.g. chlorophylls). If these chlorophyll molecules are broken down during ripening, lycopene and the remaining carotenoids contribute to the bright colors in fruits (orange, tomato, pepper, strawberry) but also in many flowers.
Occurrence and extraction
Lycopene was discovered as a red pigment in tomatoes by Pierre-Marie Alexis Millardet in 1876 . The naming was based on the Latin name of the tomato ( Lycopersicon esculentum ) in 1903 by CA Schunck.
Ripe tomatoes usually have a lycopene content of around 3 to 5 mg per 100 g of fruit, the lycopene content generally depends on the variety and the conditions of the ripening process. Also watermelons may be about this concentration of lycopene (up to 100 ppm included), which constitutes also the color of their flesh
Canned tomatoes contain considerably more lycopene at around 10 mg per 100 grams, as they are usually only harvested when they are ripe. Concentrated tomato paste contains very high concentrations of lycopene (approx. 62 mg lycopene per 100 grams). The red lattice ( Clathrus ruber ) also owes its red color to carotenoids, primarily to lycopene.
The availability of lycopene is higher for processed and heated products (e.g. tomato juice ) than for raw ones, since the plant cell structures are broken up when heated and the lycopene is released. A significant increase in absorption is achieved through the combination with fat. On an industrial scale, lycopene is extracted from tomato concentrates using organic solvents ( hexane , dichloromethane , methanol ).
With a few exceptions, the all- trans isomer (also all -E isomer) is most common in fruits and vegetables (94–96% in tomatoes), and it is also the thermodynamically most stable form. In contrast, the cis isomer (7 Z, 9 Z ) lycopene dominates in apricots with 53%, while the all-trans isomer is present in 8%. In ripe tomatoes, lycopene is stored in chromoplasts as needle-shaped crystals or embedded deep in the membrane.
Commercial use
Lycopene is declared as a carotenoid as a red food coloring (see also Carotenes (E 160a – 160f)) and is used to color foods. It is mainly used to color savory products, soups and sauces.
metabolism
admission
Due to their strongly hydrophobic character, carotenoids such as lycopene cannot dissolve in water without amphiphilicity . In the small intestine , therefore, the lipids, bile salts and phospholipids present in the bile that are made available during the digestive process mediate an inclusion in lipid micelles or chylomicrons . The better lycopene can be enclosed in micelles and thus absorbed into the brush border membrane, the higher the bioavailability. However, most of it is excreted (around 70–90%). The micelles or chylomicrons are taken up by passive diffusion . Animal studies show that humans ingest carotenoids more selectively than mice, for example. Therefore, in addition to passive diffusion, there must also be another absorption mechanism. There is evidence that lycopene is actively taken up by a scavenger receptor class B type 1 protein (SR-BI or also referred to as SR-B1). Lycopene then enters the lymphatic system .
Lycopene has a half-life of 2–3 days in the bloodstream and is present as a mixture of isomers (41–50% as cis isomer). Of the cis isomers, the (5 Z ) isomer has the largest proportion . The cis isomer could also be detected in the blood of mice fed trans -licopene , so that a cis - trans isomerization must take place in the metabolism. Lycopene passes through the blood to various organs and tissues; the highest concentrations are found in the testes , adrenal glands , liver and prostate. It has also been detected in breast milk and other body fluids along with other oxidation products.
Dismantling
In humans, lycopene is broken down with the help of β-carotene dioxygenase 2 (also known as β-β-9'-10'-carotene dioxygenase 2, BCDO2, BCO2). The mitochondrial enzyme is largely expressed in the liver and testes and splits the cis isomer into apo-10'-lycopinal. This can then be metabolized to either acid or alcohol.
Biological effect
Carotenoids, especially lycopene, are among the most effective naturally occurring quenchers for singlet oxygen 1 O 2 . This is formed, for example, by photochemical reactions during light absorption and is highly reactive. In photosynthesis, carotenes such as lycopene play an important role as a pigment in plants, photosynthetic bacteria, fungi and algae. They protect the photosynthetic apparatus from severe light damage and are an intermediate in the biosynthesis of important carotenes and xanthophylls.
Singlet oxygen can oxidize various amino acids in proteins , nucleic acids and unsaturated fatty acids . During the quenching reaction, the carotenoids change into an excited triplet state ( 1 O 2 + 1 Car → 3 O 2 + 3 Car). The carotenoids return to their basic state by releasing heat ( 3 car → 1 car + heat). The carotenoid molecules are not chemically converted during this reaction and are therefore available for further quenching processes. From in vitro measurements show that the Quenchingrate lycopene is particularly high (about twice as large as that of β-carotene and 100 times as great as with α-tocopherol ). However, this antioxidant effect found in the laboratory does not automatically mean that lycopene has a health-promoting effect. Lycopene, like other carotenoids, also intercepts harmful free radicals (nitrogen dioxide, thiyl sulphonyl radicals or ROS (e.g. O2 + -)) and thus makes them harmless.
There has been evidence that lycopene consumption leads to a reduced risk of cardiovascular disease , cancer (especially prostate cancer ), diabetes mellitus , osteoporosis and infertility. A recent, large study with around 28,000 test persons suggests, however, that there is no connection between lycopene and cancer risk. A protective effect in exertional asthma could not be shown.
Prostate cancer
Lycopene accumulates in the prostate along with other secondary metabolites of tomatoes ( e.g. polyphenols and other carotenoids ). However, it is not known whether these are effective against prostate cancer on their own or synergistically. An in vitro study (2012) showed that lycopene can inhibit the binding of certain cancer cells to the blood supply and thus prevent growth. In 2016, the results of six clinical trials were available that examined whether lycopene influenced the PSA value (prostate-specific antigen) or the prostate incidence before tumor resection or during adjuvant chemotherapy . However, due to the different results, no general statements can be made. No clinical benefit has been shown to date for castration-resistant prostate cancer. The DKFZ also warns against examples in advertising whose effectiveness has not been proven.
Whether there is a connection between the consumption of products made from tomatoes and a possible associated reduction in prostate cancer risk is still the subject of research. Many studies have been carried out on this, but the results can be interpreted as controversial. There are studies that see the risk of consuming products made from tomatoes reduced. In contrast, no significant conclusions can be drawn from other studies. One study even shows that eating tomatoes promotes the occurrence of prostate cancer. In a meta-analysis of 24 analyzed studies carried out at the end of 2016, the authors came to the conclusion that no concrete statements could yet be made. This is because the cohort studies and high quality studies examined did not yield significant results. The remaining study data can be interpreted in such a way that the consumption of tomatoes is associated with a reduced risk of disease in Asians and people from Oceania , but not in people from other parts of the world.
Cardiovascular diseases
In a placebo-controlled study (2014), daily intake of 7 mg lycopene improved endothelial dysfunction in patients with cardiovascular diseases . No effect could be seen in healthy individuals.
biosynthesis
Lycopene is formed in green plants and cyanobacteria , and the metabolic pathway used is similar. The synthesis starts with mevalonic acid , which is converted to dimethylallyl pyrophosphate . This condenses with three molecules of isopentenyl pyrophosphate to geranylgeranyl pyrophosphate . Two molecules of geranylgeranyl pyrophosphate are then combined to form phytoene . Starting from phytoene, lycopene is then formed through several intermediate stages. All- trans- lycopene is produced in bacteria by a single enzyme, phytoene desaturase (CRTI), and the bonds at positions 7, 11, 11 'and 7' are dehydrogenated. On the other hand, cyanobacteria, green algae and plants require four enzymes for biosynthesis, which is known as the poly-cis metabolic pathway. The substrate undergoes multiple dehydrogenation and isomerization, which is catalyzed by two desaturases (plant type phytoene desaturase PDS and ζ-carotene desaturase ZDS) and two isomerases (15- cis -is-carotene isomerase Z-ISO and carotene-cis-trans isomerase CRTISO) become.
Lycopene could then be further processed via β-carotene to form various xanthophylls .
literature
- Deutsches Ärzteblatt : Tomatoes and ketchup protect against prostate cancer , September 5, 2014.
- The influence of lycopene on the endothelial function of postmenopausal women , Sonja Schmidt, dissertation, 2016.
Web links
Individual evidence
- ↑ Entry on CI 75125 in the CosIng database of the EU Commission, accessed on March 11, 2020.
- ↑ Entry on E 160d: Lycopene in the European database on food additives, accessed on June 16, 2020.
- ↑ a b c d Entry on lycopene. In: Römpp Online . Georg Thieme Verlag, accessed on November 12, 2014.
- ↑ Christina Chai, WLF Armarego: Purification of Laboratory Chemicals . Elsevier, 2003, ISBN 978-0-08-051546-5 , pp. 593 ( limited preview in Google Book search).
- ↑ a b Data sheet Lycopene, ≥98% (HPLC), from tomato at Sigma-Aldrich , accessed on February 8, 2019 ( PDF ).
- ↑ a b c d e J. Shi and M. Le Maguer: Lycopene in tomatoes: chemical and physical properties affected by food processing . In: Critical Reviews in Food Science and Nutrition . tape 40 , no. 1 , January 1, 2000, p. 1-42 , doi : 10.1080 / 10408690091189275 , PMID 10674200 .
- ↑ a b c d Emmanouil H. Papaioannou et al .: Natural Origin Lycopene and Its “Green” Downstream Processing . In: Critical Reviews in Food Science and Nutrition . tape 56 , no. 4 , March 11, 2016, p. 686-709 , doi : 10.1080 / 10408398.2013.817381 , PMID 25671774 .
- ↑. Perkins-Veazie P, Collins JK, Davis AR, Roberts W .: Carotenoid content of 50 watermelon cultivars . In: Journal of Agricultural and Food Chemistry . tape 54 , no. 7 , 2006, p. 2593-7 , doi : 10.1021 / jf052066p .
- ^ John Webster and Roland WS Webster: Introduction to Fungi, p. 591, Third Edition, 2007, Cambridge University Press.
- ↑ a b Joseph Schierle et al .: Content and isomeric ratio of lycopene in food and human blood plasma . In: Food Chemistry . tape 59 , no. 3 , p. 459-465 , doi : 10.1016 / s0308-8146 (96) 00177-x .
- ↑ a b c Akihiko Nagao: Absorption and metabolism of dietary carotenoids . In: BioFactors (Oxford, England) . tape 37 , no. 2 , March 1, 2011, p. 83-87 , doi : 10.1002 / biof.151 , PMID 21488131 .
- ↑ Binxing Li et al .: Inactivity of human β, β- carotene-9 ', 10'-dioxygenase (BCO2) underlies retinal accumulation of the human macular carotenoid pigment . In: Proceedings of the National Academy of Sciences . tape 111 , no. 28 , July 15, 2014, p. 10173-10178 , doi : 10.1073 / pnas.1402526111 , PMID 24982131 .
- ↑ BCO2 beta-carotene oxygenase 2 , NCBI database.
- ↑ Kiefer et al .: Identification and characterization of a mammalian enzyme catalyzing the asymmetric oxidative cleavage of provitamin A. J. Biol. Chem. 276 / - / 2001: 14110-14116, PMID 11278918 .
- ^ A b Xiang-Dong Wang: Lycopene metabolism and its biological significance . In: The American Journal of Clinical Nutrition . tape 96 , no. 5 , November 1, 2012, p. 1214S-22S , doi : 10.3945 / ajcn.111.032359 , PMID 23053559 .
- ↑ Paolo Di Mascio et al .: Carotenoids, tocopherols and thiols as biological singlet molecular oxygen quenchers . In: Biochemical Society Transactions . tape 18 , no. 6 , December 1, 1990, pp. 1054-1056 , doi : 10.1042 / bst0181054 , PMID 2088803 .
- ↑ Avoxa & # 150; Mediengruppe Deutscher Apotheker GmbH: Pharmaceutical newspaper online: radical scavengers from tomatoes and carrots. Retrieved May 3, 2017 .
- ↑ A. Mortensen et al .: Comparative mechanisms and rates of free radical scavenging by carotenoid antioxidants . In: FEBS letters . tape 418 , no. 1-2 , November 24, 1997, pp. 91-97 , PMID 9414102 .
- ↑ Giovannuci, E. et al. (2002): A Prospective Study of Tomato Products, Lycopene and Prostate Cancer Risk. In: J Natl Cancer Inst Vol. 94, pp. 391-398, PMID 11880478 .
- ↑ Bowen P. et al .: Tomato sauce supplementation and prostate cancer: lycopene accumulation and modulation of biomarkers of carcinogenesis . In: Experimental Biology and Medicine . 227, No. 10, 2002, pp. 886-893. doi : 10.1177 / 153537020222701008 . PMID 12424330 .
- ↑ American Association for Cancer Research : No Magic Tomato? Study Breaks Link between Lycopene and Prostate Cancer Prevention , Science Daily. May 17, 2007.
- ↑ B. Falk et al .: Annals of Allergy, Asthma & Immunology . 94, No. 4, 2005, pp. 480-485.
- ↑ a b Hussain SS. Et al .: Food-based natural products for cancer management: Is the whole greater than the sum of the parts? . In: Seminars in Cancer Biology . 40–41, 2016, pp. 233–246. doi : 10.1016 / j.semcancer.2016.06.002 . PMID 27397504 .
- ^ Tomato nutrient may intercept cancer growth. ( Memento of the original from October 17, 2013 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. News from the University of Portsmouth dated February 1, 2012.
- ↑ Prostate cancer: risk factors and prevention - few triggers known , information portal of the DKFZ, accessed on January 23, 2016.
- ↑ a b Xu, X. et al .: Tomato consumption and prostate cancer risk: a systematic review and meta-analysis. . In: Sci Rep. . 6, No. 37091, 2016, pp. 1-8. doi : 10.1038 / srep37091 . PMID 27841367 .
- ^ Parag R. Gajendragadkar et al .: Effects of Oral Lycopene Supplementation on Vascular Function in Patients with Cardiovascular Disease and Healthy Volunteers: A Randomized Controlled Trial. In: PLoS ONE. 9, 2014, p. E99070, doi: 10.1371 / journal.pone.0099070 .
- ↑ aerzteblatt.de: "Tomato Pill" to improve vascular function , June 10, 2014.
- ↑ Claudia Stange: Carotenoids in Nature - Biosynthesis, Regulation and Function . Springer, Cham 2016, ISBN 978-3-319-39124-3 , pp. 45 .
- ↑ Alexander R. Moise et al .: Mechanistic aspects of carotenoid biosynthesis . In: Chemical Reviews . tape 114 , no. 1 , January 8, 2014, p. 164-193 , doi : 10.1021 / cr400106y , PMID 24175570 , PMC 3898671 (free full text).
