Title: Baicalein
CAS Registry Number: 491-67-8
CAS Name: 5,6,7-Trihydroxy-2-phenyl-4H-1-benzopyran-4-one
Additional Names: 5,6,7-trihydroxyflavone; noroxylin
Molecular Formula: C15H10O5
Molecular Weight: 270.24
Percent Composition: C 66.67%, H 3.73%, O 29.60%
Literature References: From roots of Scutellaria baicalensis. Isoln and structure: Bargellini, Gazz. Chim. Ital. 49, II, 47 (1919); Shibata et al., Acta Phytochim. 1, 109 (1923). Synthesis: Sastri, Seshadri, Proc. Indian Acad. Sci. 23A, 262 (1946), C.A. 41, 449 (1947); Schönberg et al., J. Am. Chem. Soc. 77, 5390 (1955); Jouanne, Mentzer, Compt. Rend. 254, 727 (1962); Agasimundin, Siddappa, J. Chem. Soc. Perkin Trans. 1 1973, 503. Pharmacology: Koda et al., C.A. 75, 47200d (1971).
Properties: Yellow prisms from alc, dec 264-265°. uv max (ethanol): 324, 276 nm (log e 4.18, 4.42). Sol in alcohol, methanol, ether, acetone, ethyl acetate, hot glacial acetic acid. Sparingly sol in chloroform, nitrobenzene. Practically insol in water. Sol in dil NaOH with greenish-brown color. Concd H2SO4 gives yellow color, green fluorescence.
Absorption maximum: uv max (ethanol): 324, 276 nm (log e 4.18, 4.42)
Therap-Cat: Astringent.
Keywords: Astringent.
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CAS number 491-67-8 YesY
PubChem 5281605
ChemSpider 4444924 YesY
UNII 49QAH60606 YesY
Jmol-3D images Image 1
Molecular formula C15H10O5
Molar mass 270.24 g mol−1
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Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
Infobox references

Baicalein (5,6,7-trihydroxyflavone) is a flavone, a type of flavonoid, originally isolated from the roots of Scutellaria baicalensis. It is also reported in Oroxylum indicum or Indian trumpetflower. It is the aglycone of baicalin.

The flavonoid has been shown to inhibit certain types of lipoxygenases[1] and act as an anti-inflammatory agent.[2]It has antiproliferative effects on ET-1-induced proliferation of pulmonary artery smooth muscle cell proliferation via inhibition of TRPC1 channel expression.[3] Possible antidepressant effects have also been attributed to baicalein in animal research.[4]

Baicalein is an inhibitor of CYP2C9,[5] an enzyme of the cytochrome P450 system that metabolizes drugs in the body.

A derivative of baicalin is a known prolyl endopeptidase inhibitor.[6]

It is one of the active ingredients of Sho-Saiko-To, a Japanese herbal supplement believed to enhance liver health.