Quercetagetin (Flavonol · Antiviral · Antiproliferative)
| Compound | Quercetagetin |
| Chemical class | Polyphenol — Flavonol (6-Hydroxyquercetin) |
| CAS | 1169-23-9 |
| Primary source | Tagetes erecta (African marigold, flower petals) |
| Key applications | Antiviral, antiproliferative, antioxidant |
| Claim strength | Emerging |
| Typical form | Research-grade isolate; marigold extract |
Name origin: Named after the genus Tagetes (marigold), from which it was first characterised. The suffix reflects its flavonol (quercetin-related) chemical structure. Traditional use: Marigold flowers have broad traditional use in Mesoamerican and South Asian contexts for wound healing, anti-inflammatory, and antimicrobial applications, though quercetagetin specifically has not been the focus of traditional practice — it was identified as a minor constituent during phytochemical investigation. Research trajectory: Emerging literature describes antiviral activity against several enveloped viruses and antiproliferative effects in cancer cell lines. Clinical data is absent; this remains a preclinical compound. Commercial source: Not commercially isolated at scale; available as a constituent of marigold extract or as a research-grade standard. Formulators seeking quercetagetin activity should specify marigold (Tagetes) extracts.
Evidence for Quercetagetin Applications
Antiviral activity: In vitro studies show quercetagetin inhibits flavivirus replication (dengue, Zika) and influenza neuraminidase at low micromolar concentrations, likely through direct interaction with viral envelope proteins and polymerase complexes. Mechanism studies are ongoing. Claim strength: Emerging.
Antiproliferative and pro-apoptotic effects: Cell line studies in hepatocellular, cervical, and colorectal cancer models show quercetagetin induces G2/M cell cycle arrest and caspase-dependent apoptosis at 10–50 µM concentrations. Selectivity over normal cells is reported but not yet validated in animal models. Claim strength: Emerging.
Antioxidant capacity: The additional 6-hydroxyl group relative to quercetin enhances radical-scavenging potency in ORAC and DPPH assays. Quercetagetin demonstrates higher antioxidant activity than quercetin in vitro, though bioavailability and in vivo relevance are unstudied. Claim strength: Emerging.
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Dosage & Formulator Specification
No human clinical dose has been established for quercetagetin. Preclinical active concentrations in cell-based assays are typically 5–50 µM, translating to estimated oral doses of several hundred milligrams — far above what standard marigold extract would supply.
Formulators referencing marigold extract for antioxidant or skin applications typically standardise to lutein (5–20%) or total carotenoids, with flavonols including quercetagetin as minor co-components. Quercetagetin content in commercial marigold extracts is rarely specified.
For research-blend formulations, quercetagetin is available as an analytical standard (≥98% HPLC). Scale-up supply is limited; formulators planning inclusion should plan for bespoke extraction or contact Herbuno for availability assessment.
Frequently Asked Questions — Quercetagetin
How does quercetagetin differ from quercetin?
Quercetagetin has an additional hydroxyl group at the C-6 position compared to quercetin, increasing its radical-scavenging capacity but also its susceptibility to oxidation. This structural difference may alter its receptor and enzyme binding profile.
Is quercetagetin available as a commercial ingredient?
Not at supplement scale. It is available as a research-grade analytical standard. Marigold (Tagetes) extracts contain it as a minor flavonol, but commercial specifications focus on lutein and zeaxanthin.
What is the primary commercial source of quercetagetin?
Tagetes erecta flower petals are the best-documented botanical source. Some Hibiscus and Primula species have also been reported to contain quercetagetin at trace levels.
What claim-strength label should I apply to quercetagetin in a formulation summary?
Emerging. All current evidence is in vitro or early mechanistic. No animal or human efficacy data supports stronger claims at this time.
Claim-strength scale – High = multiple human RCTs; Moderate = limited trials or strong preclinical convergence; Emerging = early-stage lab or animal data.
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