Journal of Food Bioactives, ISSN 2637-8752 print, 2637-8779 online
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Volume 10, June 2020, pages 32-46

Chemistry and biochemistry of dietary carotenoids: bioaccessibility, bioavailability and bioactivities


Figure 1.
Figure 1. Common dietary carotenoids and different isomeric structures in free and ester forms of carotenoids as represented by astaxanthin. R represents saturated or unsaturated alkyl chains.
Figure 2.
Figure 2. The biosynthetic pathway of carotenoids in plants. The colors of the frames represent the appearance of different compounds. GAP represents glyceraldehyde 3-phosphate; MEP, methylerythritol 4-phosphate; IPP, isopentenyl pyrophosphate; DMAPP, dimethylallyl pyrophosphate; GGPP, geranylgeranyl pyrophosphate. CRTISO, carotenoid isomerase; LCYB, lycopene β-cyclase; LCYE, lycopene ε-cyclase; CYP97C, carotene ε-hydroxylase; CYP97A, cytochrome P450 carotene β-hydroxylase; ZEP, zeaxanthin epoxidase; VDE, violaxanthin de-epoxidase.
Figure 3.
Figure 3. Schematic depiction of inflammatory signaling pathways and actions of carotenoids. Increased ROS causes the oxidative stress inside cells. During exposure to oxidants, IκB (inhibitors of NF-κB) proteins which are bound with NF-κB are rapidly degraded and release NF-κB protein to the nucleus. NF-κB could then bind to DNA sequences, and activate the expression of pro-inflammatory cytokines. The mitogen-activated protein kinase (MAPK) pathway activation begins with the activation of MAPKK-kinases (MAPKKKs). MAPKKKs phosphorylates MAPK-kinases (MAPKKs) subsequently, and the MAPKK further activates and phosphorylates MAPKs. Activated MAPKs then mediate the gene expression in nucleus. Certain carotenoids can inactivate the NF-κB pathway and MAPK signaling pathways to exhibit the anti-inflammatory effects.


Table 1. Quantitative distribution of common carotenoids and their predominant isomers in selected dietary foods
CarotenoidFood sources (concentration)Reference
FW, fresh weight; DW, dry weight.
all-E-luteinSquash, Sweet Momma flesh (18.6μg/g FW); Spinach (37.4μg/g FW); Kale (123.1μg/g FW); Potato, Yukon Gold flesh (4.1μg/g FW); Tomato (6.41 μg/g DW)Tsao and Yang (2006); Li et al. (2012)
13Z- or 13′Z-luteinTomato (0.76 μg/g DW)Li et al. (2012)
9Z- or 9′Z-luteinTomato (0.53 μg/g DW)Li et al. (2012)
all-E-β-caroteneCassava root, sweet yellow (7.27 μg/g FW); Squash, Sweet Momma flesh (3.7 μg/g FW); Kale (23.8 μg/g FW); Tomato (81.29 μg/g DW)Carvalho et al. (2012); Tsao and Yang (2006); Li et al. (2012)
9Z-β-caroteneCassava root, sweet yellow (0.35μg/gFW); Tomato (2.15 μg/g DW)Carvalho et al. (2012); Li et al. (2012)
13Z-β-caroteneCassava root, sweet yellow (0.5μg/gFW); Tomato (1.85 μg/g DW)Carvalho et al. (2012); Li et al. (2012)
15Z- or 15′Z-β-caroteneTomato (1.15 μg/g DW)Li et al. (2012)
all-E-lycopeneTomato (145.85 μg/g DW)Li et al. (2012)
5Z- or 5′Z-lycopeneTomato (4.24 μg/g DW)Li et al. (2012)
15Z- or 15′Z-lycopeneTomato (2.79 μg/g DW)Li et al. (2012)
13Z- or 13′Z-lycopeneTomato (2.25 μg/g DW)Li et al. (2012)
9Z- or 9′Z-lycopeneTomato (1.75 μg/g DW)Li et al. (2012)
all-E-astaxanthinAntarctic krill, boiling (90.71μg/gDW)Cong et al. (2019)
13Z-astaxanthinAntarctic krill, boiling (15.65μg/gDW)Cong et al. (2019)
9Z-astaxanthinAntarctic krill, boiling (15.39μg/gDW)Cong et al. (2019)


Table 2. Potential health effects of carotenoids and comparison among carotenoid isomers
Summary of resultsReferences
Antioxidant activities
  ABTS+ assaylycopene > β-carotene > lutein > α-tocopherolZanfini et al. (2010)
  aTEAC assaylycopene > β-carotene = α-carotene > neurosporene > phytofluene = phytoeneMüller et al. (2011)
  ABTS+ assayviolaxanthin > lutein > β-caroteneFu et al. (2011)
  DPPH assayβ-carotene > lutein > violaxanthinFu et al. (2011)
  ROO scavenging capacityastaxanthin> lutein > zeaxanthin > α-tocopherol > fucoxanthin > β-carotene > lycopeneRodrigues et al. (2012)
  HO scavenging capacityα-tocopherol > astaxanthin > zeaxanthin > fucoxanthin > lutein > β-carotene > lycopeneRodrigues et al. (2012)
  ORAC-L, PLC and CAA assays13Z-astaxanthin > all-E-astaxanthin ≈ 9Z-astaxanthinYang et al. (2017)
  DPPH assay9Z-astaxanthin > 13Z-astaxanthin > all-E-astaxanthinLiu and Osawa (2007)
  Against oxidative stress in H2O2 induced Caco-2 cells9Z-astaxanthin ≈ 13Z-astaxanthin > all-E-astaxanthinYang et al. (2017)
  Extending the median lifespan of Caenorhabditis elegans9Z-astaxanthin > all-E-astaxanthin > 13Z-astaxanthinLiu et al. (2018)
  DPPH and ORAC-L assays9Z-astaxanthin ≈ 13Z-astaxanthin > all-E-astaxanthin ≈ 13′Z-lutein > 9Z-lutein ≈ all-E-luteinYang et al. (2018); Yang et al. (2017)
  AAPH assay5Z-lycopene > all-E-lycopene ≈other Z-lycopenesMuller et al. (2011)
  TEAC assayall-E-zeaxanthin ≈ 13Z-zeaxanthin > 9Z-zeaxanthinBöhm, et al. (2002)
  Inhibiting LDL oxidationall-E-β-carotene > 9Z-β-caroteneLavy, et al. (1993)
  Rat oral-dosing test9Z-β-carotene > all-E-β-caroteneLevin, et al. (1997)
  Chemical-based assays and CAA assay3S,3′S-astaxanthin > 3R,3′R-astaxanthin > a mixture of different stereoisomers of astaxanthin (S: meso: R = 1:2:1)Liu, Luo, et al. (2016)
Anti-inflammatory activity
  Caco-2 monolayers treated with TNF-α9Z-astaxanthin ≧ 13Z-astaxanthin ≧ all-E-astaxanthinYang et al. (2019)
  Through inhibiting the nuclear NF-κB p50 subunit translocation and down-regulating the JNK activationcarotenoid extract rich in 9Z- or 9′Z-β-carotene and all-E-β-caroteneYang et al. (2013)
  Against LPS-induced inflammation in macrophagesmeso-zeaxanthin [(3R, 3′S)- β, β-carotene-3, 3′-diol]Firdous, Kuttan, and Kuttan (2015)
  Lower the production of inflammatory mediators in UV-irradiated or IL-1-treated fibroblastsphytoene and phytoflueneFuller et al. (2006)
  Through regulating pathways including Akt and MAPK pathwaysfucoxanthinCho et al. (2018)
Anti-cancer effects
  Benign prostate hyperplasia (BPH) treatment in miceZ-lycopenes ≧ all-E-lycopeneZou et al. (2014)
  Inhibiting the colon cancer cell growth3S,3′S-astaxanthin ≈ 3R,3′R-astaxanthin ≈ a mixture of different stereoisomers of astaxanthin (S: meso: R = 1:2:1)Liu, Song, et al. (2016)
  Controversial resultslycopene on prostate cancerWoodside et al. (2015)
  Controversial resultsβ-carotene on lung cancerWoodside et al. (2015)
Macular degeneration
  Protection against age-related macular degeneration (AMD)lutein and zeaxanthinTsao, R. (2006)
  Deposit in the retina of mammalsastaxanthin and luteinGuerin et al. (2003)
  Play an important role in retinal synthesisβ-caroteneMatos et al. (2017)