Glucoraphanin (Aliphatic Glucosinolate · Sulforaphane Precursor · Nrf2 · Chemopreventive)
| Compound | Glucoraphanin (GRN) |
| Chemical class | Glucosinolate — Aliphatic (4-Methylsulfinylbutyl glucosinolate) |
| CAS | 20830-75-5 |
| Primary source | Brassica oleracea var. italica (broccoli florets and sprouts) |
| Key applications | Sulforaphane precursor, Nrf2 activation, detoxification, chemopreventive |
| Claim strength | High (via sulforaphane); Moderate (as intact glucosinolate) |
| Typical form | Broccoli extract standardised to glucoraphanin; broccoli sprout powder |
| Buy from Herbuno | Broccoli Extract Powder - Brassica oleracea → |
Name origin: From Raphanus (radish genus) via the related glucosinolate glucoraphenin — glucoraphanin was first isolated in significant quantities from broccoli (Brassica oleracea). The 4-methylsulfinylbutyl side chain distinguishes it from glucoiberin (3-methylsulfinylpropyl) and glucoerucin (4-methylthiobutyl). Traditional use: Brassica vegetables (broccoli, cabbage, Brussels sprouts, kale) have been consumed as health-promoting foods since antiquity across European, Mediterranean, and Asian food traditions. The specific health-promoting properties of glucosinolates were not understood until the 20th century, though cruciferous vegetable consumption has long been associated with reduced cancer risk in epidemiological observation. Research trajectory: Glucoraphanin is the most commercially important glucosinolate — it is the stable, storage form of sulforaphane (the bioactive hydrolysis product). In the plant, glucoraphanin is stored in vacuoles; when tissue is damaged (chewing, processing), the enzyme myrosinase (stored separately) converts glucoraphanin to sulforaphane. Human gut microbiota also express glucosinolate-hydrolysing enzymes with variable efficiency. Broccoli sprouts (developed by Paul Talalay’s Johns Hopkins group, 1997) were found to contain 20–50× more glucoraphanin than mature broccoli, establishing them as a concentrated sulforaphane source. Commercial source: Broccoli Liquid Extract and Broccoli Extract Powder from Herbuno deliver glucoraphanin alongside other Brassica phytochemicals. See sourcing options below.
Evidence for Glucoraphanin Applications
Sulforaphane precursor — Nrf2 activation: Glucoraphanin’s pharmacological significance lies entirely in its conversion to sulforaphane by myrosinase. Once converted, sulforaphane is one of the most potent known dietary Nrf2 activators — inducing Phase-II detoxification enzymes (NQO1, GST, HO-1), antioxidant enzymes, and anti-inflammatory pathways. Multiple human RCTs using glucoraphanin-standardised broccoli sprout preparations confirm Nrf2 target gene induction. Claim strength: High (via sulforaphane).
Cancer chemoprevention (epidemiological and preclinical): High cruciferous vegetable consumption (and thus high glucoraphanin intake) is consistently associated with reduced risk of colorectal, lung, and breast cancer in prospective cohort studies. Randomised biomarker trials with glucoraphanin-rich broccoli sprout preparations show significant reductions in urinary aflatoxin-DNA adducts (liver cancer biomarker) in Qidong, China. Claim strength: Moderate (biomarker RCTs; no cancer incidence endpoints).
Cardiovascular and metabolic: Human intervention studies with glucoraphanin-standardised broccoli powder show reductions in LDL-C, total cholesterol, and improvements in endothelial function over 12 weeks. Glucoraphanin/sulforaphane activates AMPK and improves insulin sensitivity in animal models. Claim strength: Moderate.
Air pollution protection (urinary biomarker RCT): A randomised trial in China (Yanagita et al. / Egner et al. 2014) demonstrated that glucoraphanin-rich broccoli sprout beverage consumption significantly increased urinary excretion of benzene and acrolein metabolites — indicating enhanced detoxification of inhaled air pollutants via Phase-II enzyme induction. Claim strength: Moderate (biomarker RCT in high-pollution setting).
Broccoli Extract Powder - Brassica oleracea →
Browse Standardised Extract Powders →
Dosage & Formulator Specification
Human RCT doses from Nrf2 and chemopreventive studies: 40–200 µmol/day glucoraphanin (approximately 25–125 mg/day glucoraphanin). This is achievable from 1–5 g/day broccoli sprout extract standardised to glucoraphanin content. Specify glucoraphanin content by HPLC alongside myrosinase activity (or co-formulate with exogenous myrosinase/mustard seed powder) to ensure conversion to sulforaphane in the GI tract. Broccoli extracts processed at high temperatures may lose myrosinase activity — specify low-temperature or cold extraction to preserve enzyme activity for optimal glucoraphanin-to-sulforaphane conversion.
Important: the bioavailability of sulforaphane from glucoraphanin depends on myrosinase activity — either from intact plant enzyme (preserved by low-temperature extraction) or from gut microbial myrosinase (variable, typically 10–40% efficiency vs plant myrosinase). For guaranteed sulforaphane delivery, use sulforaphane isolate directly or co-formulate glucoraphanin with myrosinase-active mustard seed powder.
Frequently Asked Questions — Glucoraphanin
Is glucoraphanin the same as sulforaphane?
No — glucoraphanin is the stable, storage precursor; sulforaphane is the bioactive hydrolysis product. Glucoraphanin + myrosinase enzyme → sulforaphane + glucose + sulfate. Glucoraphanin is stable during extraction, storage, and processing; sulforaphane is volatile and unstable. Most commercial broccoli supplements contain glucoraphanin (the stable form), with conversion to sulforaphane occurring during digestion. Products claiming “sulforaphane” as the delivered form must verify sulforaphane stability in the finished product.
Why do broccoli sprouts have 20–50× more glucoraphanin than mature broccoli?
Broccoli sprouts (3–5 day old seedlings) synthesise high glucosinolate levels as a defence mechanism during the vulnerable seedling stage — particularly against insects and pathogens. As the plant matures and develops other defence mechanisms (structural and secondary metabolite diversity), glucosinolate concentration per gram of tissue decreases. This discovery by Talalay’s Hopkins group in 1997 established broccoli sprouts as a practical high-glucoraphanin source for human studies.
Does cooking broccoli destroy glucoraphanin?
Glucoraphanin itself is heat-stable and survives cooking. However, myrosinase enzyme is heat-sensitive — it is inactivated at temperatures above 60°C. This means cooked broccoli retains glucoraphanin but loses myrosinase activity, reducing the efficiency of glucoraphanin-to-sulforaphane conversion. Gut microbiota provide some myrosinase activity but at lower efficiency than plant enzyme. Solution: pair cooked broccoli with raw mustard seed (which has myrosinase) or allow brief pre-incubation of chopped raw broccoli at room temperature before cooking to allow myrosinase conversion before heat inactivation.
What is the optimal glucoraphanin dose for cancer chemopreventive positioning?
Human biomarker RCTs establishing Nrf2 induction and detoxification enzyme upregulation have used 40–200 µmol glucoraphanin/day (25–125 mg). At 40 µmol/day (the lower bound of effective doses), this is approximately 1–2 cups of fresh broccoli sprouts daily or 1–2 g of a high-standardisation broccoli sprout extract. For supplement positioning, the Nrf2 activation and Phase-II enzyme induction framing is appropriate; cancer prevention claims require disease-specific clinical evidence not yet available from individual supplement trials.
Related compounds: Sulforaphane, Glucobrassicin, Sinigrin, 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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