Scutellarein

Scutellarein at a Glance

Scutellarein is a flavone — 6-hydroxyapigenin, or 5,6,7,4’-tetrahydroxyflavone — best understood as apigenin with an extra hydroxyl at the 6-position. It occurs in skullcap (Scutellaria), in the Chinese medicinal daisy Erigeron breviscapus (Dengzhanhua), and scattered across the Lamiaceae, Compositae and Verbenaceae ^{1,2Reference 1Thoa NT · 2025ReviewScutellarein: a review of chemistry and pharmacologyView study →Reference 2Lai J · 2024ReviewReview on the pharmacological effects and pharmacokinetics of scutellareinView study →}.

Its single most important relationship is to scutellarin, its 7-O-glucuronide. Scutellarin is the standardised active of breviscapine / Dengzhan, a widely used injectable Chinese cerebrovascular medicine — so much of scutellarein’s real-world footprint reaches people as the glycoside, with scutellarein being the aglycone released on hydrolysis ^{2Reference 2Lai J · 2024ReviewReview on the pharmacological effects and pharmacokinetics of scutellareinView study →}. Keeping the two straight is essential: scutellarein is the free aglycone discussed here; scutellarin is the glycoside drug-lead.

The isolated aglycone shows a broad preclinical repertoire — anti-inflammatory, neuroprotective, anticancer, antiviral and antioxidant activity — but almost all of it is cell-culture and rodent work, and its poor oral bioavailability and enzyme-inhibition profile are the load-bearing caveats ^{1,3Reference 1Thoa NT · 2025ReviewScutellarein: a review of chemistry and pharmacologyView study →Reference 3Zhu SY et al. · 2013In vitroIn vitro evidence of possible influence of scutellarein towards bile acids’ metabolism — competitive inhibition of UGT1A3 (Ki ≈ 5.8 µM)View study →}. Toxicity is low.

Scutellarein vs. Scutellarin

The names differ by two letters and the molecules by one sugar, but the distinction runs through the whole page.

• Scutellarein is the aglycone — the free flavone, 6-hydroxyapigenin.
• Scutellarin is scutellarein-7-O-glucuronide — the glycoside, and the actual clinical material behind breviscapine / Dengzhan injections used for ischaemic stroke and cerebrovascular disease in China ^{2Reference 2Lai J · 2024ReviewReview on the pharmacological effects and pharmacokinetics of scutellareinView study →}.

In the living plant the compound is stored mostly as the glycoside; scutellarein is liberated when that glucuronide is hydrolysed, including by gut microbiota after oral dosing ^{3Reference 3Zhu SY et al. · 2013In vitroIn vitro evidence of possible influence of scutellarein towards bile acids’ metabolism — competitive inhibition of UGT1A3 (Ki ≈ 5.8 µM)View study →}. This matters for evidence because the human cerebrovascular record belongs to the glycoside (given by injection precisely because oral absorption is poor), while most mechanistic studies of the aglycone are in vitro or in rodents. Two rat stroke studies found the aglycone gave better focal-ischaemia protection than scutellarin itself, which is part of why the free flavone is studied as a lead in its own right ^{4,5Reference 4Qian L et al. · 2012AnimalSynthesis and protective effect of scutellarein on focal cerebral ischemia/reperfusion in ratsView study →Reference 5Wu WY et al. · 2018AnimalProtective effect of 6-O-methyl-scutellarein on repeated cerebral ischemia/reperfusion in ratsView study →}. Cross-reference the parent apigenin (scutellarein minus the 6-OH) and the batch-mate cirsimaritin (scutellarein’s 6,7-dimethyl ether).

What It's Used For

Scutellarein’s activity is real and mechanistically specific in places — a direct Src-kinase inhibitor, an EZH2/FOXO1 modulator, a SARS-helicase binder — but the discipline of the compound page applies hard: nearly everything is isolate work in cells or rodents, and the only human-scale efficacy signal is carried by the glycoside scutellarin, not the aglycone ^{1,2Reference 1Thoa NT · 2025ReviewScutellarein: a review of chemistry and pharmacologyView study →Reference 2Lai J · 2024ReviewReview on the pharmacological effects and pharmacokinetics of scutellareinView study →}.

Evidence by IndicationStrength of support · Beta

Support is an experimental score — weighted by study type (human > animal > in vitro) and volume. A beta, not a validated metric. Every row is preclinical isolate work (the human data belong to the glycoside), so scores stay modest by design.

01Anti-InflammatoryShaky40%Direct Src/Syk inhibition → NF-κB/MAPK; macrophage isolate models ^{6,7,8Reference 6Park MY et al. · 2022Scutellarein inhibits LPS-induced inflammation through NF-κB/MAPKs signaling pathway in RAW264.7 cellsView study →Reference 7Sung NY et al. · 2015Scutellarein reduces inflammatory responses by inhibiting Src kinase activityView study →Reference 8Kim E et al. · 2014Syk/Src-targeted anti-inflammatory activity of Codariocalyx motorius ethanolic extractView study →}

02Neuroprotective / CerebrovascularShaky36%Rat focal ischaemia–reperfusion (aglycone > scutellarin); neurological reviews ^{4,5,9Reference 4Qian L et al. · 2012AnimalSynthesis and protective effect of scutellarein on focal cerebral ischemia/reperfusion in ratsView study →Reference 5Wu WY et al. · 2018AnimalProtective effect of 6-O-methyl-scutellarein on repeated cerebral ischemia/reperfusion in ratsView study →Reference 9Kumar R et al. · 2025Therapeutic role of scutellarein in neurological disordersView study →}

03AnticancerShaky32%Ovarian A2780/SKOV-3 apoptosis via EZH2/FOXO1 ^{10Reference 10Lang X et al. · 2021Scutellarein induces apoptosis and inhibits proliferation, migration, and invasion in ovarian cancer via inhibition of EZH2/FOXO1 signalingView study →}

04AntiviralShaky30%SARS-helicase inhibition; influenza replication (GlyRS) in vitro ^{11,12Reference 11Keum YS · 2012Development of chemical inhibitors of the SARS coronavirus: viral helicase as a potential targetView study →Reference 12Zhang J et al. · 2025Glycyl-tRNA synthetase as a target for antiviral drug screening against influenza virusView study →}

05AntioxidantShaky24%Radical scavenging / iron-chelation as an extract flavone ^{1,13Reference 1Thoa NT · 2025ReviewScutellarein: a review of chemistry and pharmacologyView study →Reference 13Liu L et al. · 2023Scutellarein alleviates chronic obstructive pulmonary disease through inhibition of ferroptosis by chelating iron and interacting with arachidonate 15-lipoxygenaseView study →}

Mechanisms

The kinase story (Src/Syk → NF-κB) is the load-bearing mechanism; the antiviral targets are the most distinctive; and the UGT/CYP inhibition sits in the table as a caution, not a benefit.

Pharmacokinetics

The defining PK fact is poor oral bioavailability — the reason the clinical form of this chemistry is the injected glycoside scutellarin rather than an oral aglycone tablet ^{2,3Reference 2Lai J · 2024ReviewReview on the pharmacological effects and pharmacokinetics of scutellareinView study →Reference 3Zhu SY et al. · 2013In vitroIn vitro evidence of possible influence of scutellarein towards bile acids’ metabolism — competitive inhibition of UGT1A3 (Ki ≈ 5.8 µM)View study →}. Scutellarein is extensively glucuronidated (it is, after all, the aglycone of a glucuronide), and the interconversion between aglycone and glycoside — including microbial hydrolysis of scutellarin back to scutellarein in the gut — shapes its exposure ^{3Reference 3Zhu SY et al. · 2013In vitroIn vitro evidence of possible influence of scutellarein towards bile acids’ metabolism — competitive inhibition of UGT1A3 (Ki ≈ 5.8 µM)View study →}. A specific and important finding is that scutellarein inhibits UDP-glucuronosyltransferases (UGTs) and cytochrome-P450 enzymes, which both limits its own clearance predictability and flags a herb–drug-interaction risk ^{3Reference 3Zhu SY et al. · 2013In vitroIn vitro evidence of possible influence of scutellarein towards bile acids’ metabolism — competitive inhibition of UGT1A3 (Ki ≈ 5.8 µM)View study →}. Robust human ADME for the isolate — Cmax, half-life, absolute oral bioavailability — is not established; most PK is animal or in-vitro, and the human numbers that exist describe scutellarin.

Clinical Trials

There are no controlled efficacy trials of isolated scutellarein. The human clinical footprint belongs to the glycoside scutellarin (breviscapine / Dengzhan) in cerebrovascular disease, given largely by injection ^{2Reference 2Lai J · 2024ReviewReview on the pharmacological effects and pharmacokinetics of scutellareinView study →}. Everything on the aglycone is preclinical.

Last checked: July 2026.

Isolate vs. Plant Studies

Scutellarein’s evidence is almost entirely the isolated aglycone in cells and rodents — the Src-kinase, EZH2/FOXO1, SARS-helicase and cerebral-ischaemia studies all test the pure compound (or a close derivative) ^{4,7,10,11Reference 4Qian L et al. · 2012AnimalSynthesis and protective effect of scutellarein on focal cerebral ischemia/reperfusion in ratsView study →Reference 7Sung NY et al. · 2015Scutellarein reduces inflammatory responses by inhibiting Src kinase activityView study →Reference 10Lang X et al. · 2021Scutellarein induces apoptosis and inhibits proliferation, migration, and invasion in ovarian cancer via inhibition of EZH2/FOXO1 signalingView study →Reference 11Keum YS · 2012Development of chemical inhibitors of the SARS coronavirus: viral helicase as a potential targetView study →}. That is a mechanistic strength but a translational weakness, because the concentrations used often exceed what the molecule’s poor oral absorption could plausibly deliver in a person ^{3Reference 3Zhu SY et al. · 2013In vitroIn vitro evidence of possible influence of scutellarein towards bile acids’ metabolism — competitive inhibition of UGT1A3 (Ki ≈ 5.8 µM)View study →}. The one place the chemistry reaches humans is a different molecule: the glycoside scutellarin, delivered by injection as breviscapine/Dengzhan for cerebrovascular disease ^{2Reference 2Lai J · 2024ReviewReview on the pharmacological effects and pharmacokinetics of scutellareinView study →}. As a plant-extract constituent (skullcap, senna) scutellarein is one flavone among many in whole-extract antioxidant assays, rarely the isolated variable ^{17Reference 17Ahmed SI et al. · 2016Pharmacologically active flavonoids from the anticancer, antioxidant and antimicrobial extracts of Cassia angustifolia VahlView study →}. The correct framing: strong isolate mechanism + real human evidence for the glycoside + essentially no human data for the aglycone.

Prevalence in Nature

Scutellarein occurs across three plant families — Lamiaceae (notably Scutellaria, the skullcaps), Compositae/Asteraceae (notably Erigeron breviscapus, the Dengzhanhua daisy that is the commercial source of scutellarin), and Verbenaceae ^{1Reference 1Thoa NT · 2025ReviewScutellarein: a review of chemistry and pharmacologyView study →}. In Scutellaria baicalensis (Chinese skullcap/Huang Qin) and S. lateriflora (American skullcap) it sits alongside the genus’s characteristic free-B-ring flavones (baicalein, wogonin) and their glycosides ^{2Reference 2Lai J · 2024ReviewReview on the pharmacological effects and pharmacokinetics of scutellareinView study →}.

The crucial point about its occurrence is speciation of form: in the living plant the compound is present largely as its 7-O-glucuronide, scutellarin, rather than as the free aglycone, so quantitative figures for free scutellarein are scarce and it is often reported qualitatively ^{2,3Reference 2Lai J · 2024ReviewReview on the pharmacological effects and pharmacokinetics of scutellareinView study →Reference 3Zhu SY et al. · 2013In vitroIn vitro evidence of possible influence of scutellarein towards bile acids’ metabolism — competitive inhibition of UGT1A3 (Ki ≈ 5.8 µM)View study →}. It has also been isolated as a pharmacologically active flavone from senna (Cassia angustifolia) leaf, reported there for the first time in that work ^{17Reference 17Ahmed SI et al. · 2016Pharmacologically active flavonoids from the anticancer, antioxidant and antimicrobial extracts of Cassia angustifolia VahlView study →}. Because the aglycone is usually a hydrolysis product of the glycoside, its measured “abundance” depends heavily on extraction and work-up.

Discovery & Synthesis

Scutellarein was not introduced by a single datable isolation but emerged through twentieth-century flavonoid chemistry as the aglycone of scutellarin, the Scutellaria/Erigeron glucuronide — its name deriving from the genus Scutellaria ^{1Reference 1Thoa NT · 2025ReviewScutellarein: a review of chemistry and pharmacologyView study →}. Structurally it is 6-hydroxyapigenin (5,6,7,4’-tetrahydroxyflavone), placing it one hydroxyl group away from apigenin and two methyls away from cirsimaritin. It can be obtained by hydrolysing scutellarin (removing the 7-O-glucuronide) and by total synthesis; medicinal-chemistry work continues on synthetic routes and on derivatives (e.g. 6-O-methyl-scutellarein) aimed at improving the aglycone’s poor bioavailability ^{1,5Reference 1Thoa NT · 2025ReviewScutellarein: a review of chemistry and pharmacologyView study →Reference 5Wu WY et al. · 2018AnimalProtective effect of 6-O-methyl-scutellarein on repeated cerebral ischemia/reperfusion in ratsView study →}. Commercial supply of the clinical material is the glycoside, extracted from Erigeron breviscapus as breviscapine/Dengzhan; the free aglycone is chiefly a research chemical ^{2Reference 2Lai J · 2024ReviewReview on the pharmacological effects and pharmacokinetics of scutellareinView study →}.

Patents: not yet researched.

Toxicity & Safety

Scutellarein carries a low toxicity flag — consistent with a dietary-type polyhydroxy flavone and with the long clinical use of its glycoside scutellarin. The meaningful caveat is not acute toxicity but a pharmacokinetic interaction risk and the near-total absence of isolate safety characterisation in humans.

Safety at a Glance

✅ Low / no toxicity

• Low intrinsic toxicity. A tetrahydroxy flavone with no acute-toxicity signal at studied doses; its glycoside scutellarin has an extensive clinical safety record in cerebrovascular use ^{2Reference 2Lai J · 2024ReviewReview on the pharmacological effects and pharmacokinetics of scutellareinView study →}.
• Enzyme-inhibition / interaction risk. Scutellarein inhibits UGTs and CYP450 enzymes, so co-administration with drugs cleared by those routes is a theoretical herb–drug-interaction concern ^{3Reference 3Zhu SY et al. · 2013In vitroIn vitro evidence of possible influence of scutellarein towards bile acids’ metabolism — competitive inhibition of UGT1A3 (Ki ≈ 5.8 µM)View study →}.
• Poor oral bioavailability. Little of an oral dose is absorbed intact, so isolate potency in vitro should not be read as an oral effect in people ^{3Reference 3Zhu SY et al. · 2013In vitroIn vitro evidence of possible influence of scutellarein towards bile acids’ metabolism — competitive inhibition of UGT1A3 (Ki ≈ 5.8 µM)View study →}.
• Human isolate safety not characterised. No dedicated human toxicology, genotoxicity or repeat-dose dataset exists for the free aglycone; the safety inference borrows from the glycoside and the flavone class.

Reproductive and developmental toxicity have not been characterised for the isolated aglycone; any such decision belongs to the herb or product where intake is decided, not to this molecule page. No comprehensive isolate genotoxicity or repeat-dose package is established here beyond the class-level and interaction points above.

Dosage

There is no established or recommended human dose for isolated scutellarein. Cited figures in the literature are preclinical rodent research doses or in-vitro concentrations (e.g. the 25–100 µM used in the ovarian-cancer work ^{10Reference 10Lang X et al. · 2021Scutellarein induces apoptosis and inhibits proliferation, migration, and invasion in ovarian cancer via inhibition of EZH2/FOXO1 signalingView study →}) and are not convertible to human self-dosing. The only human-scale dosing for this chemistry is the glycoside scutellarin (breviscapine / Dengzhan), given largely by injection for cerebrovascular indications — a different molecule and a different route ^{2Reference 2Lai J · 2024ReviewReview on the pharmacological effects and pharmacokinetics of scutellareinView study →}. These are research figures, not a personal recommendation.

References

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5. Wu WY, Zhong Y, Lu YT, et al. (2018). Protective effect of 6-O-methyl-scutellarein on repeated cerebral ischemia/reperfusion in rats. Journal of Asian Natural Products Research. https://pubmed.ncbi.nlm.nih.gov/28971689/
6. Park MY, Ha SE, Kim HH, et al. (2022). Scutellarein inhibits LPS-induced inflammation through NF-κB/MAPKs signaling pathway in RAW264.7 cells. Molecules. https://pubmed.ncbi.nlm.nih.gov/35744907/
7. Sung NY, Kim MY, Cho JY (2015). Scutellarein reduces inflammatory responses by inhibiting Src kinase activity. Korean Journal of Physiology & Pharmacology. https://pubmed.ncbi.nlm.nih.gov/26330757/
8. Kim E, Yoon KD, Lee WS, et al. (2014). Syk/Src-targeted anti-inflammatory activity of Codariocalyx motorius ethanolic extract. Journal of Ethnopharmacology. https://pubmed.ncbi.nlm.nih.gov/24866386/
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10. Lang X, Chen Z, Yang X, et al. (2021). Scutellarein induces apoptosis and inhibits proliferation, migration, and invasion in ovarian cancer via inhibition of EZH2/FOXO1 signaling. Journal of Biochemical and Molecular Toxicology. https://pubmed.ncbi.nlm.nih.gov/34350670/
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13. Liu L, Zhang Y, Wang L, et al. (2023). Scutellarein alleviates chronic obstructive pulmonary disease through inhibition of ferroptosis by chelating iron and interacting with arachidonate 15-lipoxygenase. Phytotherapy Research. https://pubmed.ncbi.nlm.nih.gov/37353982/
14. Wang Y, Tan L, Jiao K, et al. (2022). Scutellarein attenuates atopic dermatitis by selectively inhibiting transient receptor potential vanilloid 3 channels. British Journal of Pharmacology. https://pubmed.ncbi.nlm.nih.gov/35771623/
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