Broccoli Sprouts and the Health Benefits of Sulforphane


When raw or lightly steamed broccoli or raw broccoli sprouts are chewed, glucoraphanin and the enzyme myrosinase is released.  The function of the myrosinase enzyme is to catalyze the hydrolysis of a class of compounds called glucosinolates. Glucoraphanin is a glucosinolate.  Myrosinase transforms the glucoraphanin into sulforaphane, the active compound that exhibits anti-cancer and antimicrobial properties in experimental models.

Nature has designed myrosinase and its natural substrate, glucosinolate, to be part of the plant’s defense response. When the plant is attacked by pathogens, insects, or other herbivore, the plant uses myrosinase to convert glucosinolates, which are otherwise-benign, into toxic products like isothiocyanates, thiocyanates, and nitriles.

There are a number of plants in nature that use the myrosinase-glucosinolate defense system.  They include:

  • Bok choy
  • Broccoli
  • Broccoli Sprouts
  • Cabbage
  • Cauliflower
  • Daikon (Raphanus sativus)
  • Daikon Sprouts
  • Garden cress (Lepidium sativum)
  • Kale
  • Rape seed (Brassica napus)
  • Wasabi (Wasabia japonica)
  • White mustard (Sinapis alba)
  • Yellow mustard (Brassica juncea)

In 1994, scientists discovered that three-to-four-day-old broccoli sprouts had 20 times the concentration of glucoraphanin than full grown broccoli. 

Specifically, there is 73 mg of glucoraphanin for broccoli sprouts versus v. 11 mg of glucoraphanin for broccoli per serving.  This results in one ounce of broccoli sprouts containing as much glucoraphanin as over 1.25 pounds (20 ounces) of broccoli.

The presence of myrosinase in the plant is needed to convert glucoraphanin into sulforaphane, otherwise glucoraphanin provides zero protective effects.

FigureX_GR Hydrolysis

The raw plant obviously contains the enzyme myrosinase.  However, myrosinase will be denatured at high temperatures and thus lose its activity when cooked. 

Cooking broccoli or other myrosinase/glucorphanin plants by boiling or microwave may destroy the myrosinase.  Reserachers compared boiled, microwaved and steamed broccoli, and found that steaming broccoli for up to five minutes was the best way to retain its myrosinase. Boiling and microwaving broccoli for one minute or less destroyed the majority of the enzyme, according to Elizabeth Jeffery, a researcher at University of Illinois at Urbana-Champaign.

Broccoli sprouts or Daikon sprouts are often eaten raw and therefore contain the myrosinase enzyme intact.

An alternative to eating broccoli spouts is consuming broccoli sprout powders and/or capsules.  However, many of these products are produced from myrosinase-inactive sprout or seed extracts.  It becomes difficult to determine which broccoli sprout powder or capsule contain the essential precursor glucoraphanin as well as the active myrosinase enzyme. Without the myrosinase enzyme intact, there is no conversion of the glucoraphanin to sulforaphane.

The potential problem with broccoli sprout powders or capsule is in the extraction process used by the manufacturer.  It is believed that this extraction process often destroys and renders the myrosinase enzyme inactive.

The safest way to insure that you are consuming glucorahanin and myrosinase together is to eat fresh broccoli sprouts.  Broccoli seeds and sprouting jars can be purchased at a health food store or online. 

A further option is to eat broccoli sprouts with daikon sprouts.  Daikon and its sprouts are known to contain myrosinase.

If cruciferous vegetables are cooked via boiling or microwave, another option to insure sulforaphane production is to eat some myrosinase-rich raw daikon radish with the meal.


An article appeared in The British Journal of Nutrition in May 2012 written by Cramer JM, Teran-Garcia M, and Jeffery EH in which they used air-dried broccoli sprouts to provide the myrosinase enzyme in this study.

Their studies indicated that about 4/5 of the glucorophanine in the broccoli sprouts is converted into sulforaphane during eating and digestion because the sprouts contain active enzyme. Combining broccoli sprout powder with enzyme-empty broccoli powder allowed the enzymes from the sprouts to convert about half of the glucoraphanin in the inert powder into sulforaphane.

Only about one-fifth of the glucoraphanin was converted into sulforaphane when just broccoli powder was consumed.

The abstract of this important study follows:

“Sulforaphane (SF) is a chemopreventive isothiocyanate (ITC) derived from the myrosinase-catalyzed hydrolysis of glucoraphanin, a thioglucoside present in broccoli. Broccoli supplements often contain glucoraphanin but lack myrosinase, putting in question their ability to provide dietary SF. This study compared the relative absorption of SF from air-dried broccoli sprouts rich in myrosinase and a glucoraphanin-rich broccoli powder lacking myrosinase, individually and in combination. Subjects (n = 4) each consumed 4 meals consisting of dry cereal and yogurt with 2 g sprouts, 2 g powder, both, or neither. Blood and urine were analyzed for SF metabolites. The 24 h urinary SF recovery was 74%, 49%, and 19% of the dose ingested from broccoli sprouts, combination, and broccoli powder meals, respectively. Urinary and plasma ITC appearance was delayed from the broccoli powder compared to the sprouts and combination. A liver function panel indicated no toxicity from any treatment at 24 h. These data indicate a delayed appearance in plasma and urine of SF from the broccoli powder relative to SF from myrosinase-rich sprouts. Combining broccoli sprouts with the broccoli powder enhanced SF absorption from broccoli powder, offering the potential for development of foods that modify the health impact of broccoli products.”  [1]  [2]

The following table is a representation of the epidemiological evidence of cancer prevention by cruciferous vegetables.

Epidemiological Evidence of Cancer Prevention by Cruciferous Vegetables

Site of cancer

Amount of crucifers eaten

RR – relative risk OR-odds ratio (P value)



>5 servings/week

RR 0.49 (0.008)

Michaud et al. (1999)


>5 servings/week

RR 0.67 (0.03)

Zhang et al. (2000)


5 servings/week

OR 0.61 (0.006)

Kolonel et al. (2000)


>3 servings/week

OR 0.50 (0.02)

Cohen et al. (2000)

Colon (men)

Top 20%

RR 0.76 (0.011)

Voorips et al. (2000)

Colon (women)

Top 20%

RR 0.51 (0.004)

Voorips et al. (2000)


Top 25%

OR 0.05 (0.01)

Fowke et al. (2003)


Top 25%

OR 0.53 (0.001)

Yuan et al. (1998)

Source: E.H. Jeffery, Phytochemical Review, 2008.


Table:  Health Benefits of Broccoli Sprouts (Sulforaphane)

Broccoli Sprouts (Sulforaphane)













Chemo protective





Sulforaphane is a promising chemo preventive agent that exerts its effect by strong induction of phase 2 enzymes via activation of Nrf2



Cervical Cancer





Sulforaphane may stimulate the apoptosis (cell death) of Cervical Cancer cells








Sulforaphane may help to prevent Leukemia



Liver Cancer





Sulforaphane may stimulate the apoptosis (cell death) of Liver Cancer cells



Lung Cancer





Sulforaphane may help to prevent Lung Cancer








Sulforaphane may help to prevent Melanoma



Mouth Cancer





Sulforaphane may help to prevent Mouth Cancer



Ovarian Cancer





Sulforaphane may stimulate the apoptosis (cell death) of Ovarian Cancer cells



Pancreatic Cancer





Sulforaphane may help to prevent and treat Pancreatic Cancer



Tongue Cancer





Sulforphane may help to prevent Tongue Cancer



Helicobacter pylori





Broccoli Sprouts may facilitate the eradication of Helicobacter pylori.








CUR + SFN and PEITC + SFN combinations could be more effective than used alone in preventing inflammation and possibly its associated diseases including cancer.



Skin Tumors





Mice were exposed to damaging levels of UV light for 20 weeks in a study conducted at Johns Hopkins Medical School. Following the exposure, application of sulforaphane resulted in a 50% reduction in the number of mice with tumors.



Breast Cancer





Study results revealed the women who had eaten higher levels of Brassica vegetables—broccoli, cabbage, cauliflower and kale—all of which contain glucoraphanin and related compounds—were 50% less likely to be diagnosed with breast cancer.



Prostate Cancer





Human prostate cancer cells responded to treatment with sulforaphane in the form of broccoli sprout extracts, showing dramatic increases in their Phase 2 protective enzymes.



Colon Cancer





Ability of sulforaphane and broccoli sprouts extracts to inhibit cancer in vitro in human colon cancer cells.



Bladder Cancer





Studies have also shown sulforaphane and broccoli sprout extract can induce apoptosis and cell cycle arrest in human bladder cancer cells in vitro



Stomach Cancer





Dual actions of sulforaphane in inhibiting Helicobacter infections and blocking gastric tumor formation offer hope that these mechanisms might function synergistically to provide diet-based protection against gastric cancer in humans












Sulforaphane-induced Phase 2 enzymes from broccoli sprouts improved cardiovascular health by decreasing inflammation and improving heart, artery and kidney function








Delayed administration (15 min) of a single dose of SUL significantly decreased cerebral infarct volume following focal ischemia












Broccoli Sprouts may lower total serum Cholesterol levels



Glucose metabolism





Sulforaphane promotes lipolysis via hormone sensitive lipase activation mediated by decreasing AMPK signal activation in adipocytes.








Results suggest sulforaphane from broccoli may help reverse the damaging effects of diabetes-linked vascular disease







Macular Degeneration





Ability of sulforaphane to protect retinal pigment epithelial cells from damage by chemical carcinogens and by ultraviolet light


Musculo- Skeletal System










Sulforaphane may be useful for the treatment of Rheumatoid Arthritis







Phase II Enzyme inducer





Study identified sulforaphane as a very potent phase II enzyme inducer in brocooli and noted that sulforaphane induces both quinone reductase and glutathione transferase activities in several mouse tissues








Oral sulforaphane safely and effectively induces mucosal Phase II enzyme expression in the upper airway of human subjects








Broccoli sprouts are an exceptionally rich source of inducers of enzymes that protect against chemical carcinogens.



Nrf2 Activation





Activates a transcription factor, Nrf2 in the cell












Sulforaphane Shows Promise in Autism Spectrum Disorder



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