Phenethyl Isothiocyanate — PEITC (Aromatic Isothiocyanate · Carcinogen Detox · STAT3 Inhibition)
| Compound | Phenethyl Isothiocyanate (PEITC) |
| Chemical class | Glucosinolate Hydrolysis Product — Aromatic Isothiocyanate |
| CAS | 2257-09-2 |
| Primary source | Hydrolysis of gluconasturtiin in Nasturtium officinale (watercress) by myrosinase |
| Key applications | CYP2E1 inhibition, tobacco carcinogen detoxification, Nrf2 activation, STAT3 inhibition, anticancer |
| Claim strength | Moderate |
| Typical form | Watercress extract (PEITC or gluconasturtiin); PEITC isolate |
| Buy from Herbuno |
Watercress Extract Powder (Nasturtium officinale) → Watercress Leaf Liquid Extract (Water Soluble) - Nasturtium officinale → |
Name origin: Phenethyl (2-phenylethyl group: a phenyl ring + CH2CH2) + isothiocyanate (—N=C=S). PEITC is the aromatic isothiocyanate from gluconasturtiin hydrolysis — the 2-phenylethyl version of the isothiocyanate class. The phenylethyl group gives it greater lipophilicity than aliphatic isothiocyanates (AITC) and different CYP enzyme selectivity from sulforaphane (methylsulfinylbutyl isothiocyanate). Traditional use: Watercress consumption has traditional associations with respiratory and blood-cleansing health. PEITC itself was identified in the 1970s as a constituent of watercress and has since become a primary research focus for tobacco carcinogen detoxification. Research trajectory: PEITC has an excellent human bioavailability profile — it is rapidly absorbed after watercress consumption and detected in plasma and urine within hours. Its primary clinical evidence base is for tobacco carcinogen (NNK, PAH) detoxification in smokers via CYP2E1/1A1 inhibition, documented in the Hecht 2011 crossover RCT. PEITC also has strong STAT3 inhibitory activity (a transcription factor overactivated in many cancers), distinguishing it from sulforaphane in its anticancer mechanism profile. Commercial source: Watercress Extract Powder and Watercress Leaf Liquid Extract from Herbuno deliver PEITC (if myrosinase-active extract) or gluconasturtiin (for in vivo conversion). See sourcing options below.
Evidence for PEITC Applications
Tobacco carcinogen detoxification (human RCT): The Hecht 2011 crossover RCT in smokers (85 g/day fresh watercress, delivering approximately 15–20 mg PEITC) significantly reduced urinary metabolites of NNK (a potent lung carcinogen) and total PAH-DNA adducts, confirming CYP2E1 inhibition and enhanced detoxification in humans. This is the most directly clinically validated application for PEITC in humans. Claim strength: Moderate (crossover RCT; biomarker endpoints).
Nrf2 activation and Phase-II enzyme induction: PEITC is a potent Nrf2 activator via Keap1 cysteine alkylation, inducing GST, NQO1, and HO-1. In comparative studies, PEITC is approximately equal to or slightly more potent than sulforaphane for Nrf2 activation in some cell models. Human biomarker studies with watercress confirm Phase-II enzyme induction. Claim strength: Moderate.
STAT3 inhibition — anticancer: PEITC inhibits STAT3 (Signal Transducer and Activator of Transcription 3), a transcription factor constitutively activated in many solid tumours (breast, prostate, lung, colon, ovarian, head and neck cancers). STAT3 inhibition by PEITC reduces cancer cell survival, proliferation, and angiogenesis. This mechanism is distinct from sulforaphane’s primary Keap1/Nrf2 mechanism and gives PEITC a differentiated anticancer profile. Claim strength: Moderate (preclinical convergent; limited human data).
HDAC inhibition (epigenetic): PEITC inhibits HDAC1 and HDAC3 (class I HDACs) in cancer cell lines, promoting re-expression of silenced tumour suppressor genes. This epigenetic chemopreventive mechanism complements Nrf2 activation and STAT3 inhibition. Claim strength: Moderate.
Watercress Extract Powder (Nasturtium officinale) →
Watercress Leaf Liquid Extract (Water Soluble) - Nasturtium officinale →
Browse Standardised Extract Powders →
Dosage & Formulator Specification
Human clinical dose (Hecht RCT): 85 g/day fresh watercress delivering 15–20 mg PEITC equivalent. For watercress extract: 1–3 g/day standardised extract (request HPLC gluconasturtiin + PEITC content on CoA). PEITC itself is volatile and pungent — encapsulation in enteric-coated or soft gelatin capsules with a carrier is recommended for oral formulations. Myrosinase-active watercress extract provides in situ PEITC generation; myrosinase-inactive extract provides stable gluconasturtiin for gut microbial conversion. For standardised supplement formulation, isolated PEITC provides precise dosing but requires careful stability management (nitrogen flushing, amber sealed containers).
Frequently Asked Questions — PEITC
How does PEITC differ from sulforaphane in its anti-cancer mechanism?
Sulforaphane’s primary mechanism is Keap1 alkylation Nrf2 release Phase-II enzyme induction (chemopreventive, cytoprotective). PEITC shares Nrf2 activation but additionally and distinctively inhibits STAT3 (overactivated in many cancers, driving cancer cell survival). PEITC also more potently inhibits CYP2E1 (tobacco carcinogen activation) than sulforaphane. The two have complementary but non-identical mechanisms, making them rationally synergistic in a comprehensive cancer chemopreventive formulation.
Is PEITC safe for cancer patients?
PEITC at dietary watercress intake levels is considered safe for the general population and for cancer patients in most contexts. However, PEITC’s CYP3A4 inhibitory activity (at higher concentrations) and STAT3 modulatory effects could theoretically interact with cancer chemotherapy drugs metabolised by CYP3A4 (many antineoplastics). Cancer patients should consult their oncologist before using concentrated watercress extract supplements during active treatment. Standard dietary watercress consumption is generally considered safe.
Why is watercress consumption particularly recommended for smokers?
The NNK tobacco carcinogen is activated by CYP2E1 to the proximate carcinogen that attacks lung DNA. PEITC inhibits CYP2E1 (the activating enzyme) while inducing GST (the conjugating enzyme that eliminates NNK metabolites). This dual mechanism simultaneously blocks carcinogen activation and enhances carcinogen elimination — a pharmacological strategy directly relevant to reducing lung cancer risk in smokers. The Hecht 2011 RCT quantified this effect as reduced urinary NNK metabolites in watercress-consuming smokers.
Can PEITC from watercress extract be positioned for a detox supplement?
Yes — PEITC’s mechanism (Phase-II enzyme induction, CYP2E1 inhibition) directly enhances the body’s natural detoxification pathways for electrophilic carcinogens, air pollutants, and environmental toxins. “Supports the body’s natural detoxification processes” is the appropriate positioning — distinct from dubious “detox” claims that imply removing unspecified toxins. The Nrf2 induction and tobacco carcinogen biomarker data provide legitimate mechanistic support for a detoxification enzyme-support positioning.
Related compounds: Gluconasturtiin, Sulforaphane, Allyl Isothiocyanate, Indole-3-Carbinol
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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