Baicalein

Baicalein (5,6,7-trihydroxyflavone) is a flavone, a type of flavonoid,^[1] originally isolated from the roots of Scutellaria baicalensis and Scutellaria lateriflora. It is also a constituent of Oroxylum indicum (Indian trumpetflower) and thyme.^[2] It is the aglycone of baicalin.

Baicalein

Clinical data
Other names	Biacalein; Noroxylin
Identifiers
IUPAC name 5,6,7-trihydroxy-2-phenyl-4H-1-benzopyran-4-one
CAS Number	491-67-8
PubChem CID	5281605
IUPHAR/BPS	5144
ChemSpider	4444924
UNII	49QAH60606
KEGG	C10023
ChEBI	CHEBI:2979
ChEMBL	ChEMBL8260
CompTox Dashboard (EPA)	DTXSID2022389
ECHA InfoCard	100.164.911
Chemical and physical data
Formula	C15H10O5
Molar mass	270.240 g·mol−1
3D model (JSmol)	Interactive image
SMILES O=C\1c3c(O)c(O)c(O)cc3O/C(=C/1)c2ccccc2
InChI InChI=1S/C15H10O5/c16-9-6-11(8-4-2-1-3-5-8)20-12-7-10(17)14(18)15(19)13(9)12/h1-7,17-19H Key:FXNFHKRTJBSTCS-UHFFFAOYSA-N

Pharmacology

Baicalein, along with its glucuronide baicalin, is a positive allosteric modulator of the benzodiazepine site and a non-benzodiazepine site of the GABA_A receptor, but with an affinity over 250× lower than diazepam.^[3][4][5] It displays subtype selectivity for α₂ and α₃ subunit-containing GABA_A receptors.^[6]

The flavonoid has been shown to inhibit certain types of lipoxygenases.^[7]

Baicalein is an inhibitor of CYP2C9,^[8] an enzyme of the cytochrome P450 system that metabolizes drugs in the body.

A derivative of baicalin is a known prolyl endopeptidase inhibitor.^[9]

See also

• List of compounds with carbon number 15