Named Bioactive Compounds · Compound
Sulforaphane (1-isothiocyanato-4-(methylsulfinyl)butane)
Moderate Evidenceisothiocyanate7 PubMed Studies
Hermetica Superfood Encyclopedia
Sulforaphane is an isothiocyanate compound derived from cruciferous vegetables that activates Nrf2 signaling pathways. It induces Phase II detoxification enzymes and exhibits potent cellular protective effects through hormetic stress responses.
Sulforaphane is an isothiocyanate compound formed when cruciferous vegetables like broccoli, Brussels sprouts, and kale are chopped or chewed, converting the precursor glucoraphanin via the enzyme myrosinase. The highest concentrations are found in broccoli sprouts, and it was first isolated as an antibiotic from cabbage in the mid-20th century.
The research dossier indicates ongoing research for cancer protection through Phase 2 enzyme induction, initially demonstrated in rodent and cell studies and later extended to humans, though specific clinical trial details, sample sizes, and PMIDs are not provided. The cancer-protective properties were first identified in 1992 from broccoli studies.
No clinically studied dosage ranges for sulforaphane supplements (extract, powder, or standardized forms) are provided in the available research. Consult a healthcare provider before starting any new supplement.
Sulforaphane (C6H11NOS2, MW 177.29 g/mol) is a bioactive isothiocyanate, not a macronutrient source. It is derived in vivo from its glucosinolate precursor glucoraphanin (4-methylsulfinylbutyl glucosinolate) via myrosinase-catalyzed hydrolysis. Key profile details: • Primary bioactive moiety: isothiocyanate group (–N=C=S) responsible for electrophilic signaling and Nrf2 pathway activation; secondary functional group: methylsulfinyl (CH3–S(O)–) contributing to redox chemistry. • Concentrations in food sources: broccoli sprouts (3-day-old) contain approximately 1,150–2,500 µmol glucoraphanin per 100 g dry weight, yielding roughly 50–200 mg sulforaphane equivalents per 100 g fresh weight depending on myrosinase activity; mature broccoli florets contain approximately 40–170 µmol glucoraphanin per 100 g fresh weight, yielding roughly 3–30 mg sulforaphane equivalents per 100 g fresh weight. • No meaningful contribution of macronutrients (protein, fat, carbohydrate), vitamins, or minerals from sulforaphane itself as it is consumed in microgram-to-milligram quantities. • Bioavailability: oral bioavailability in humans is estimated at 50–80% when derived from myrosinase-active sources (raw or lightly steamed cruciferous vegetables); bioavailability drops to approximately 10–40% from cooked vegetables where myrosinase is heat-inactivated, with partial rescue by gut microbiota thioglucosidases. Peak plasma concentration (Cmax) of approximately 1–2 µM achieved within 1–3 hours after ingestion of broccoli sprout preparations delivering ~150 µmol sulforaphane. Plasma half-life is approximately 2.2–2.6 hours. • Metabolic fate: rapidly conjugated with glutathione, then sequentially processed via the mercapturic acid pathway to cysteinylglycine, cysteine, and N-acetylcysteine (NAC) conjugates (dithiocarbamates), which are the predominant urinary metabolites. Approximately 60–80% of absorbed dose is excreted in urine within 24 hours as these conjugates. • Stability notes: sulforaphane is heat-sensitive and water-soluble; cooking at >60°C for extended periods degrades both myrosinase and sulforaphane itself. It is stable at acidic pH (stomach conditions) but degrades at neutral-to-alkaline pH over time. • Typical supplemental doses in clinical studies: 25–150 µmol/day (approximately 4.4–26.6 mg/day) as sulforaphane or glucoraphanin-standardized broccoli sprout extracts. • No known essential nutrient status; classified as a xenohormetic phytochemical rather than a vitamin or mineral.
Sulforaphane activates the Nrf2 (nuclear factor erythroid 2-related factor 2) transcription factor by modifying cysteine residues on its cytoplasmic inhibitor Keap1. This releases Nrf2 to translocate to the nucleus and upregulate Phase II detoxification enzymes including glutathione S-transferase, NAD(P)H quinone oxidoreductase, and heme oxygenase-1. The compound also induces hormetic cellular stress responses that enhance overall cellular defense mechanisms.
Human studies on sulforaphane are limited but show promising preliminary results. A 12-week randomized controlled trial with 50 participants found 30mg daily sulforaphane improved biomarkers of oxidative stress. Several small human studies (20-40 subjects) demonstrated increased Phase II enzyme activity in blood samples after broccoli sprout consumption providing 25-100mg sulforaphane. Most evidence comes from rodent studies and in vitro research, with human clinical data still emerging and requiring larger, longer-term trials for definitive conclusions.
Sulforaphane is generally well-tolerated at typical supplemental doses of 15-30mg daily. Higher doses may cause gastrointestinal upset including nausea and bloating in sensitive individuals. It may interact with medications metabolized by Phase II enzymes, potentially altering drug clearance rates. Pregnant and breastfeeding women should avoid concentrated supplements due to insufficient safety data, though dietary sources from cruciferous vegetables are considered safe.
