Herbacetin

Herbacetin is a flavonol compound found in flaxseed, rosehip, and certain herbs that exerts biological activity primarily through modulation of mitochondrial apoptotic pathways and inhibition of pro-inflammatory enzymes. Its most studied mechanisms involve induction of programmed cell death in hepatocellular carcinoma cells and suppression of inducible nitric oxide synthase (iNOS) via JNK and NF-κB signaling.

Origin & History

Herbacetin is a natural flavonol aglycone (3,5,7,8,4'-pentahydroxyflavone) found primarily in flaxseed (Linum usitatissimum) and Ephedrae herba. It appears as a light yellow to yellow crystalline solid with molecular formula C15H10O7 and is isolated as a plant metabolite structurally related to kaempferol.

Historical & Cultural Context

No historical or traditional medicinal uses are documented for herbacetin in available sources. The compound has been identified solely as a modernly studied plant metabolite without reference to traditional medicine systems.

Health Benefits

• May support liver health through apoptosis induction in HepG2 liver cancer cells (25-100 μM induced dose-dependent effects via mitochondrial pathways - preliminary evidence only)
• Potential anti-inflammatory activity by inhibiting nitric oxide synthase (iNOS) in macrophages via JNK and NF-κB pathways (PMID: 26297979 - cell-based evidence)
• May help reduce cancer cell motility by suppressing HGF-induced movement in MDA-MB-231 breast cancer cells through c-Met and Akt inhibition (PMID: 24081687 - preliminary)
• Possible antiviral properties through SARS-CoV main protease inhibition (EC 3.4.22.69 - in vitro evidence only)
• Potential regulation of cellular growth via ornithine decarboxylase inhibition, blocking polyamine biosynthesis (preclinical mechanistic studies)

How It Works

Herbacetin induces apoptosis in HepG2 liver cancer cells through the intrinsic mitochondrial pathway, triggering cytochrome c release and caspase cascade activation at concentrations of 25–100 μM in vitro. It suppresses inflammatory signaling by inhibiting iNOS expression in LPS-activated macrophages through downregulation of JNK phosphorylation and NF-κB nuclear translocation, reducing downstream nitric oxide production. Additionally, herbacetin has demonstrated inhibitory activity against alpha-glucosidase and pancreatic lipase enzymes, suggesting potential metabolic effects through digestive enzyme modulation.

Scientific Research

No human clinical trials, RCTs, or meta-analyses have been conducted on herbacetin to date. All available evidence comes from preclinical in vitro and cell-based studies, including research on HepG2 liver cancer cells showing mitochondria-dependent apoptosis, RAW264.7 macrophage studies demonstrating iNOS inhibition (PMID: 26297979), and MDA-MB-231 breast cancer cell studies showing motility suppression (PMID: 24081687).

Clinical Summary

Current evidence for herbacetin is limited entirely to in vitro cell culture studies and animal model experiments; no published human clinical trials exist as of early 2025. In HepG2 hepatocellular carcinoma cell lines, concentrations of 25–100 μM produced dose-dependent apoptosis, though these concentrations are not directly translatable to human plasma levels achievable through supplementation. Anti-inflammatory effects were demonstrated in murine macrophage models (RAW 264.7 cells) treated with lipopolysaccharide, where herbacetin measurably reduced nitric oxide output and iNOS protein expression. The overall evidence base is preliminary, and efficacy and safety in humans remain unestablished.

Nutritional Profile

Herbacetin (3,5,7,8-tetrahydroxyflavone; C₁₅H₁₀O₇; MW 302.24 g/mol) is a naturally occurring flavonol aglycone — not a macronutrient source. It provides no significant calories, protein, fat, fiber, or carbohydrates. Key details: • Chemical class: Hydroxylated flavonol (a subclass of flavonoids), structurally related to kaempferol but with an additional hydroxyl group at the C-8 position on the A-ring. • Natural sources and approximate concentrations: Found in Rhodiola rosea (roseroot) — reported at ~0.1–0.5 mg/g dry weight in rhizome extracts; detected in Linum usitatissimum (flaxseed) hulls, often as glycosidic conjugates (herbacetin-3-O-glucoside, herbacetin diglucoside) at trace to low-mg/g levels; present in Ephedra species and some Gossypium (cotton) flowers. • Bioactive compound profile: Functions primarily as a polyphenolic antioxidant; exhibits radical-scavenging capacity (ORAC and DPPH assays show activity comparable to or moderately lower than quercetin); the C-8 hydroxyl group enhances metal chelation capacity relative to kaempferol. • Bioavailability notes: Like most flavonol aglycones, herbacetin has limited oral bioavailability (estimated <5–10% absorption in animal models); undergoes extensive Phase II metabolism (glucuronidation and sulfation) in the intestinal epithelium and liver; glycosidic forms (e.g., herbacetin-3-O-glucoside) require hydrolysis by intestinal β-glucosidases or gut microbiota before absorption of the aglycone; plasma concentrations following dietary intake from whole-food sources (e.g., flaxseed, Rhodiola supplements) are typically in the low nanomolar range, substantially below the micromolar concentrations (25–100 μM) used in most in vitro bioactivity studies; lipid-based delivery systems or co-administration with piperine may modestly improve absorption, though human pharmacokinetic data remain very limited. • Vitamins and minerals: Herbacetin itself contains no vitamins or minerals; however, its plant sources (Rhodiola rosea, flaxseed) provide additional micronutrients and co-occurring bioactives (rosavins, salidroside in Rhodiola; lignans, ALA in flaxseed) that may contribute to synergistic biological effects. • Solubility: Poorly water-soluble; moderately soluble in ethanol, DMSO, and alkaline aqueous solutions. LogP ~1.5–2.0, indicating moderate lipophilicity.

Preparation & Dosage

No clinically studied dosages exist as herbacetin has not been tested in humans. Preclinical cell culture studies used concentrations of 25-100 μM. No standardized forms or recommended human doses have been established. Consult a healthcare provider before starting any new supplement.

Synergy & Pairings

Kaempferol, quercetin, flaxseed lignans, vitamin C, resveratrol

Safety & Interactions

No human safety data or formal toxicology trials for isolated herbacetin supplementation have been published, making definitive risk assessment impossible at this time. Because herbacetin modulates NF-κB signaling, theoretical interactions exist with immunosuppressant drugs such as corticosteroids or calcineurin inhibitors, though these have not been studied directly. Pregnant or breastfeeding individuals should avoid isolated herbacetin supplements due to a complete absence of safety data in these populations. Individuals taking anticoagulants or anti-platelet medications should exercise caution, as flavonols as a class have demonstrated variable effects on platelet aggregation in preclinical models.