Gluconasturtiin (Aromatic Glucosinolate · PEITC Precursor · Lung Chemopreventive)

Compound	Gluconasturtiin
Chemical class	Glucosinolate — Aromatic (2-Phenylethyl glucosinolate)
CAS	499-30-9
Primary source	Nasturtium officinale (watercress), Barbarea vulgaris (yellow rocket)
Key applications	PEITC precursor, Nrf2 activation, DNA protection, lung cancer chemopreventive research
Claim strength	Moderate
Typical form	Watercress extract standardised to gluconasturtiin; watercress powder
Buy from Herbuno	Watercress Extract Powder (Nasturtium officinale) → Watercress Leaf Liquid Extract (Water Soluble) - Nasturtium officinale →

Name origin: From Nasturtium officinale (watercress — the plant, not the ornamental flower also called Nasturtium which is Tropaeolum majus). Gluconasturtiin is the 2-phenylethyl glucosinolate — an aromatic glucosinolate with a two-carbon chain connecting the phenyl ring to the glucosinolate core. It is the primary glucosinolate of watercress and is the precursor to phenethyl isothiocyanate (PEITC). Traditional use: Watercress (Nasturtium officinale) has been consumed as a health-promoting food across European, British, and Asian traditions since antiquity. Traditional associations with respiratory health, blood-cleansing, and anti-cancer properties are consistent with modern phytochemical findings. Watercress has one of the highest concentrations of gluconasturtiin of any commonly consumed vegetable. Research trajectory: Gluconasturtiin/PEITC has a well-developed research record for lung cancer chemopreventive potential — particularly in smokers. Human bioavailability studies confirm high PEITC absorption from gluconasturtiin via both plant myrosinase and gut microbial conversion. PEITC inhibits CYP2E1 and CYP1A1/2 (tobacco carcinogen-activating enzymes) while inducing Phase-II detoxification enzymes (GST, NQO1, HO-1). Commercial source: Watercress Extract Powder and Watercress Leaf Liquid Extract from Herbuno. See sourcing options below.

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Evidence for Gluconasturtiin Applications

Lung cancer chemopreventive (smoker studies): A landmark crossover RCT (Hecht et al. 2011) in smokers compared watercress consumption (85 g/day fresh watercress) vs control and found significant reduction in urinary metabolites of the tobacco carcinogens NNK (a potent lung carcinogen) and PAHs. The inhibition of NNK metabolism (CYP2E1 inhibition by PEITC) is the proposed mechanism. This human biomarker evidence is among the strongest for any dietary chemopreventive compound. Claim strength: Moderate (biomarker RCT; no lung cancer incidence endpoint).

Nrf2 activation and Phase-II enzyme induction: PEITC (from gluconasturtiin hydrolysis) is a potent Nrf2 activator — more potent than sulforaphane in some cell-based comparisons. Induces GST (glutathione S-transferase), NQO1, and HO-1, increasing detoxification capacity for electrophilic carcinogens. Human urinary biomarker studies confirm Phase-II enzyme induction from watercress gluconasturtiin. Claim strength: Moderate.

Antiproliferative: PEITC induces apoptosis in multiple cancer cell lines (prostate, breast, leukemia, lung) via multiple mechanisms: ROS generation, mitochondrial pathway, HDAC inhibition, and STAT3 inhibition. In human prostate cancer xenograft animal models, PEITC significantly reduces tumour volume. Claim strength: Moderate (preclinical convergent; human pilot data limited).

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Dosage & Formulator Specification

Human biomarker studies: 85 g/day fresh watercress (delivering approximately 30–60 mg gluconasturtiin/day — converted to 15–35 mg PEITC). For standardised watercress extract, request HPLC-verified gluconasturtiin content alongside PEITC content (if hydrolysis has occurred). Watercress is one of the most accessible commercial sources of aromatic glucosinolates for supplement formulation. Specify whether extract is myrosinase-active (for in situ PEITC generation) or myrosinase-inactivated (providing stable gluconasturtiin for gut microbial conversion). For chemopreventive supplement positioning, emphasise Nrf2 activation and detoxification enzyme induction rather than direct cancer claims.

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Frequently Asked Questions — Gluconasturtiin

Is watercress the same as Tropaeolum majus (nasturtium)?
No — watercress (Nasturtium officinale) and garden nasturtium (Tropaeolum majus) share the common name “nasturtium” but are botanically unrelated. Watercress is a Brassicaceae (mustard family) aquatic plant; Tropaeolum majus is in the Tropaeolaceae family. Both contain gluconasturtiin (and thus both taste peppery/pungent due to PEITC), but they are different plants. The scientific literature on gluconasturtiin and PEITC uses watercress (Nasturtium officinale) as the primary source.

Why is gluconasturtiin particularly relevant for smokers?
Tobacco smoke contains NNK (4-methylnitrosamino-1-(3-pyridyl)-1-butanone) and PAHs (polycyclic aromatic hydrocarbons) — potent lung carcinogens that require metabolic activation by CYP2E1 and CYP1A1/2 enzymes to become DNA-reactive. PEITC (from gluconasturtiin) inhibits these activating CYP enzymes while simultaneously inducing Phase-II detoxification enzymes (GST, NQO1). This dual mechanism — blocking carcinogen activation while enhancing carcinogen elimination — creates the rationale for watercress as a tobacco carcinogen-neutralising food. The Hecht RCT demonstrated this mechanism in human smokers via urinary biomarker reduction.

How does gluconasturtiin compare to glucoraphanin for Nrf2 activation?
PEITC (from gluconasturtiin) and sulforaphane (from glucoraphanin) are both isothiocyanates and both potent Nrf2 activators, but they differ in potency and specificity. PEITC is generally more potent than sulforaphane for CYP enzyme inhibition (relevant for tobacco carcinogen detoxification) and for HDAC inhibition (epigenetic chemopreventive mechanism). Sulforaphane has the stronger clinical data volume for Nrf2 activation across multiple conditions. The two have complementary mechanisms and are rationally combined in comprehensive chemopreventive formulations.

Can watercress extract be marketed for respiratory health?
Traditional watercress associations with respiratory health (expectorant, decongestant) have some mechanistic support — PEITC has mild TRPA1-activating activity (similar to mustard/horseradish) that may stimulate mucociliary clearance. The stronger evidence base is for carcinogen detoxification. For a respiratory health claim, emphasis on Nrf2-mediated antioxidant protection of lung tissue from environmental pollutants is the most defensible framing, consistent with the Hecht RCT data.

Related compounds: Sinigrin, Glucoraphanin, Phenethyl Isothiocyanate, Sulforaphane

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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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