Daphnetin
{{Chembox
| ImageFile = Daphnetin.svg
| ImageSize = 200px
| ImageAlt =
| IUPACName = 7,8-Dihydroxy-2H-chromen-2-one
| OtherNames = 7,8-Dihydroxycoumarin
| Section1 = {{Chembox Identifiers
| CASNo = 486-35-1
| ChEBI = 17313
| ChEMBL = 244948
| ChemSpiderID = 4444191
| EC_number = 207-632-8
| PubChem = 5280569
| UNII = XC84571RD2
| KEGG = C03093
| StdInChI=1S/C9H6O4/c10-6-3-1-5-2-4-7(11)13-9(5)8(6)12/h1-4,10,12H
| StdInChIKey = ATEFPOUAMCWAQS-UHFFFAOYSA-N
| SMILES = C1=CC(=C(C2=C1C=CC(=O)O2)O)O
}}
| Section2 = {{Chembox Properties
| C = 9 | H = 6 | O = 4
| Appearance =
| Density =
| MeltingPtC = 256
| MeltingPt_ref = {{Cite book | title = Merck Index | edition = 11th | id = 2816. Daphnetin | page = 2818 }}
| BoilingPt =
| Solubility =
}}
| Section3 = {{Chembox Hazards
| GHS_ref=[https://pubchem.ncbi.nlm.nih.gov/compound/5280569#section=Safety-and-Hazards]
| GHSPictograms = {{GHS07}}
| GHSSignalWord = Warning
| HPhrases = {{H-phrases|315|319}}
| PPhrases = {{P-phrases|264|264+265|280|302+352|305+351+338|321|332+317|337+317|362+364 }}
| MainHazards =
| FlashPt =
| AutoignitionPt =
}}
}}
Daphnetin is a chemical compound with the molecular formula {{chem2|C9H6O4}}. It has been isolated from plants of the genus Daphne.{{cite journal | doi = 10.1107/S0567740876004275 | title = Daphnetin, isolated from Daphne odora | date = 1976 | last1 = Ueno | first1 = K. | last2 = Saito | first2 = N. | journal = Acta Crystallographica Section B Structural Crystallography and Crystal Chemistry | volume = 32 | issue = 3 | pages = 946–948 | bibcode = 1976AcCrB..32..946U }}{{cite journal | doi = 10.1515/znc-1986-0301 | title = Biosynthesis of Daphnetin in Daphne mezereum L | date = 1986 | last1 = Brown | first1 = Stewart A. | journal = Zeitschrift für Naturforschung C | volume = 41 | issue = 3 | pages = 247–252 | doi-access = free }} It has also been found in Matricaria chamomilla (chamomile).{{Cite journal |last1=Petruľová-Poracká |first1=Veronika |last2=Repčák |first2=Miroslav |last3=Vilková |first3=Mária |last4=Imrich |first4=Ján |date=2013-11-01 |title=Coumarins of Matricaria chamomilla L.: Aglycones and glycosides |url=https://www.sciencedirect.com/science/article/pii/S0308814613003051 |journal=Food Chemistry |language=en |volume=141 |issue=1 |pages=54–59 |doi=10.1016/j.foodchem.2013.03.004 |pmid=23768326 |issn=0308-8146|url-access=subscription }}
It a crystalline solid with a melting point of 256 °C. It is soluble in boiling water.
Daphnetin can undergo enzymatic glycosylation to yield its 7-O-glucoside which is called daphnin (daphnetin 7-β-D-glucopyranoside). The reaction is catalyzed by the enzyme O-dihydroxy coumarin 7-O-glucosyltransferase.{{Cite journal |last1=Ibrahim |first1=Ragai K. |last2=Boulay |first2=Bernard |date=1980-05-01 |title=Purification and some properties of UDP-glucose:o-dihydroxycoumarin7-O-glucosyltransferase from tobacco cell cultures |url=https://dx.doi.org/10.1016/0304-4211%2880%2990048-6 |journal=Plant Science Letters |language=en |volume=18 |issue=2 |pages=177–184 |doi=10.1016/0304-4211(80)90048-6 |issn=0304-4211 |access-date=2022-04-03 |archive-date=2024-02-01 |archive-url=https://web.archive.org/web/20240201080728/https://www.sciencedirect.com/science/article/abs/pii/0304421180900486?via%3Dihub |url-status=live |url-access=subscription }}{{Cite journal |last1=Ueno |first1=Katsuhiko |last2=Sato |first2=Mitsuhiko |last3=Saito |first3=Norio |date=1983-06-01 |title=The Crystal and Molecular Structure of Daphnin Dihydrate: 7-(β-D-Glucopyranosyloxy)-8-hydroxycoumarin Dihydrate |journal=Bulletin of the Chemical Society of Japan |volume=56 |issue=6 |pages=1577–1580 |doi=10.1246/bcsj.56.1577 |issn=0009-2673 |doi-access=free}}
Daphnetin shows several neuroprotective and anti-inflammatory effects on the inhibition of the TLR4/NF-κB mediated inflammatory signaling pathway. They also could inhibit the IKKs/IkBa/NF-κB, AKT, and the Src/FAK/ERK1/2 multi-target medication signaling pathway for anti-angiogenesis and cancer.{{Cite journal |last1=Liu |first1=Jia |last2=Chen |first2=Qianxue |last3=Jian |first3=Zhihong |last4=Xiong |first4=Xiaoxing |last5=Shao |first5=Lingmin |last6=Jin |first6=Tong |last7=Zhu |first7=Xiqun |last8=Wang |first8=Lei |date=2016-12-29 |title=Daphnetin Protects against Cerebral Ischemia/Reperfusion Injury in Mice via Inhibition of TLR4/NF-κB Signaling Pathway |journal=BioMed Research International |language=en |volume=2016 |pages=e2816056 |doi=10.1155/2016/2816056 |issn=2314-6133 |pmc=5227117 |pmid=28119924 |doi-access=free}}
Daphnetin has been reported to be a strong sensitizer, which means that this compound and its glycosidic derivatives (e.g. daphnin) can be a cause of allergic reactions.