Histopathology image classification: Highlighting the gap between manual analysis and AI automation
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| Names | |
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| IUPAC name
(3S,5R,6M,3′S,5′R,6′S)-5′,6′-Epoxy-5,3′-dihydroxy-8′-oxo-6,7-didehydro-5,6,5′,6′,7′,8′-hexahydro-β,β-caroten-3-yl acetate
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| Systematic IUPAC name
(1S,3R,4M)-3-Hydroxy-4-{(3E,5E,7E,9E,11E,13E,15E,17E)-18-[(1S,4S,6R)-4-hydroxy-2,2,6-trimethyl-7-oxabicyclo[4.1.0]heptan-1-yl]-3,7,12,16-tetramethyl-17-oxooctadeca-1,3,5,7,9,11,13,15,17-nonaen-1-ylidene}-3,5,5-trimethylcyclohexyl acetate | |
| Identifiers | |
3D model (JSmol)
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| 3DMet | |
| 6580822 | |
| ChEBI | |
| ChEMBL | |
| ChemSpider | |
| ECHA InfoCard | 100.212.315 |
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| KEGG | |
PubChem CID
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| UNII | |
CompTox Dashboard (EPA)
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| Properties | |
| C42H58O6 | |
| Molar mass | 658.920 g·mol−1 |
| Hazards | |
| GHS labelling: | |
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| Warning | |
| H319 | |
| P264, P280, P305+P351+P338, P337+P313 | |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Fucoxanthin is a xanthophyll, with formula C42H58O6. It is found as an accessory pigment in the chloroplasts of brown algae and most other heterokonts, giving them a brown or olive-green color. Fucoxanthin absorbs light primarily in the blue-green to yellow-green part of the visible spectrum, peaking at around 510-525 nm by various estimates and absorbing significantly in the range of 450 to 540 nm.
Function
Carotenoids are pigments produced by plants and algae and play a role in light harvesting as part of the photosynthesis process. Xanthophylls are a subset of carotenoids, identified by the fact that they are oxygenated either as hydroxyl groups or as epoxide bridges. This makes them more water soluble than carotenes such as beta-carotene. Fucoxanthin is a xanthophyll that contributes more than 10% of the estimated total production of carotenoids in nature.[1] It is an accessory pigment found in the chloroplasts of many brown macroalgae, such as Fucus spp., and the golden-brown unicellular microalgae, the diatoms. It absorbs blue and green light at bandwidth 450-540 nm, imparting a brownish-olive color to algae. Fucoxanthin has a highly unique structure that contains both an epoxide bond and hydroxyl groups along with an allenic bond (two adjacent carbon-carbon double bonds) and a conjugated carbonyl group (carbon-oxygen double bond) in the polyene chain. All of these features provide fucoxanthin with powerful antioxidant activity.[2]
In macroalgal plastids, fucoxanthin acts like an antenna for light harvesting and energy transfer in the photosystem light harvesting complexes.[3] In diatoms like Phaeodactylum tricornutum, fucoxanthin is protein-bound along with chlorophyll to form a light harvesting protein complex.[4] Fucoxanthin is the dominant carotenoid, responsible for up to 60% of the energy transfer to chlorophyll a in diatoms [5] When bound to protein, the absorption spectrum of fucoxanthin expands from 450-540 nm to 390-580 nm, a range that is useful in aquatic environments.[6]
Sources
Fucoxanthin is present in brown seaweeds and diatoms and was first isolated from Fucus, Dictyota, and Laminaria by Willstätter and Page in 1914.[7] Seaweeds are commonly consumed in south-east Asia and certain countries in Europe, while diatoms are single-cell planktonic microalgae characterized by a golden-brown color, due to their high content of fucoxanthin. Generally, diatoms contain up to 4 times more fucoxanthin than seaweed, making diatoms a viable source for fucoxanthin industrially.[8] Diatoms can be grown in controlled environments (such as photobioreactors). Brown seaweeds are mostly grown in the open sea, often exposed to metals and metalloids.[9]
Bioavailability
Limited studies of fucoxanthin in humans indicate low bioavailability.[7]
See also
References
- ^ Dembitsky VM, Maoka T (November 2007). "Allenic and cumulenic lipids". Progress in Lipid Research. 46 (6): 328–75. doi:10.1016/j.plipres.2007.07.001. PMID 17765976.
- ^ Hu T, Liu D, Chen Y, Wu J, Wang S (March 2010). "Antioxidant activity of sulfated polysaccharide fractions extracted from Undaria pinnitafida in vitro". International Journal of Biological Macromolecules. 46 (2): 193–8. doi:10.1016/j.ijbiomac.2009.12.004. PMID 20025899.
- ^ Owens TG, Wold ER (March 1986). "Light-Harvesting Function in the Diatom Phaeodactylum tricornutum: I. Isolation and Characterization of Pigment-Protein Complexes". Plant Physiology. 80 (3): 732–8. doi:10.1104/pp.80.3.732. PMC 1075192. PMID 16664694.
- ^ Guglielmi G, Lavaud J, Rousseau B, Etienne AL, Houmard J, Ruban AV (September 2005). "The light-harvesting antenna of the diatom Phaeodactylum tricornutum. Evidence for a diadinoxanthin-binding subcomplex" (PDF). The FEBS Journal. 272 (17): 4339–48. doi:10.1111/j.1742-4658.2005.04846.x. PMID 16128804.
- ^ Papagiannakis E, van Stokkum IH, Fey H, Büchel C, van Grondelle R (November 2005). "Spectroscopic characterization of the excitation energy transfer in the fucoxanthin-chlorophyll protein of diatoms". Photosynthesis Research. 86 (1–2): 241–50. doi:10.1007/s11120-005-1003-8. PMID 16172942.
- ^ Premvardhan L, Sandberg DJ, Fey H, Birge RR, Büchel C, van Grondelle R (September 2008). "The charge-transfer properties of the S2 state of fucoxanthin in solution and in fucoxanthin chlorophyll-a/c2 protein (FCP) based on stark spectroscopy and molecular-orbital theory". The Journal of Physical Chemistry B. 112 (37): 11838–53. doi:10.1021/jp802689p. PMC 2844098. PMID 18722413.
- ^ a b Peng J, Yuan JP, Wu CF, Wang JH (2011-10-10). "Fucoxanthin, a marine carotenoid present in brown seaweeds and diatoms: metabolism and bioactivities relevant to human health". Marine Drugs. 9 (10): 1806–28. doi:10.3390/md9101806. PMC 3210606. PMID 22072997.
- ^ Wang LJ, Fan Y, Parsons RL, Hu GR, Zhang PY, Li FL (January 2018). "A Rapid Method for the Determination of Fucoxanthin in Diatom". Marine Drugs. 16 (1): 33. doi:10.3390/md16010033. PMC 5793081. PMID 29361768.
- ^ Li H, Ji H, Shi C, Gao Y, Zhang Y, Xu X, Ding H, Tang L, Xing Y (April 2017). "Distribution of heavy metals and metalloids in bulk and particle size fractions of soils from coal-mine brownfield and implications on human health". Chemosphere. 172: 505–515. doi:10.1016/j.chemosphere.2017.01.021. PMID 28104559.
