Broccoli Sprouts and the Health Benefits of Sulforphane

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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.

Sulforaphane

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)

Reference

Bladder

>5 servings/week

RR 0.49 (0.008)

Michaud et al. (1999)

Lymphoma

>5 servings/week

RR 0.67 (0.03)

Zhang et al. (2000)

Prostate

5 servings/week

OR 0.61 (0.006)

Kolonel et al. (2000)

Prostate

>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)

Breast

Top 25%

OR 0.05 (0.01)

Fowke et al. (2003)

Kidney

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)

 

 

 

Biosystem

Condition

Benefit

Reference

Immunity

 

 

 

 

Chemo protective

 

 

 

 

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

 [3]

 

Cervical Cancer

 

 

 

 

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

 [4]

 

Leukemia

 

 

 

 

Sulforaphane may help to prevent Leukemia

 [5]

 

Liver Cancer

 

 

 

 

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

 [6]

 

Lung Cancer

 

 

 

 

Sulforaphane may help to prevent Lung Cancer

 [7]

 

Melanoma

 

 

 

 

Sulforaphane may help to prevent Melanoma

 [8]

 

Mouth Cancer

 

 

 

 

Sulforaphane may help to prevent Mouth Cancer

 [9]

 

Ovarian Cancer

 

 

 

 

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

 [10]

 

Pancreatic Cancer

 

 

 

 

Sulforaphane may help to prevent and treat Pancreatic Cancer

 [11]

 

Tongue Cancer

 

 

 

 

Sulforphane may help to prevent Tongue Cancer

 [12]

 

Helicobacter pylori

 

 

 

 

Broccoli Sprouts may facilitate the eradication of Helicobacter pylori.

 [13]

 

Inflammation

 

 

 

 

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

 [14]

 

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.

 [15]

 

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.

 [16]

 

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.

 [17]

 

Colon Cancer

 

 

 

 

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

 [18]

 

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

 [19]

 

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

 [20]

Cardiovascular

 

 

 

 

Hypertension

 

 

 

 

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

 [21]

 

Stroke

 

 

 

 

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

 [22]

Metabolism

 

 

 

 

Cholesterol

 

 

 

 

Broccoli Sprouts may lower total serum Cholesterol levels

 [23]

 

Glucose metabolism

 

 

 

 

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

 [24]

 

Diabetes

 

 

 

 

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

 [25]

Eye/Vision

 

 

 

 

Macular Degeneration

 

 

 

 

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

 [26]

Musculo- Skeletal System

 

 

 

 

Arthritis

 

 

 

 

Sulforaphane may be useful for the treatment of Rheumatoid Arthritis

 [27]

Detoxification

 

 

 

 

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

 [28]

 

Respiratory

 

 

 

 

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

 [29]

 

Carcinogens

 

 

 

 

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

 [30]

 

Nrf2 Activation

 

 

 

 

Activates a transcription factor, Nrf2 in the cell

 [31]

Neurological

 

 

 

 

Autism

 

 

 

 

Sulforaphane Shows Promise in Autism Spectrum Disorder

 [32]



References:


[3] Hecht, S. S.  Chemoprevention of cancer by isothiocyanates, modifiers of carcinogen metabolism.  Journal of Nutrition.  129:768-774, 1999.

Misiewicz, I., et al.  Sulforaphane and 2-oxohexyl isothiocyanate induce cell growth arrest and apoptosis in L-1210 leukemia and ME-18 melanoma cells.  Oncol Rep.  10(6):2045-2050, 2003.

Nestle, M.  Broccoli sprouts in cancer prevention.  Nutrition Reviews.  46(4 Part I):127, 1998.

Thimmulappa, R. K., et al.  Identification of Nrf2-regulated genes induced by the chemopreventive agent sulforaphane by oligonucleotide microarray.  Cancer Research.  62(18):5196-5203, 2002.

Zhang, Y., et al.  A major inducer of anticarcinogenic protective enzymes from broccoli:  isolation and elucidations of structure.  Proceedings of the National Academy of Sciences USA.  89:2399-2403, 1992.

[4] Park, S. Y., et al.  Induction of apoptosis by isothiocyanate sulforaphane in human cervical carcinoma HeLa and hepatocarcinoma HepG2 cells through activation of caspase-3.  Oncol Rep.  18(1):181-187, 2007.

[5] Misiewicz, I., et al.  Sulforaphane and 2-oxohexyl isothiocyanate induce cell growth arrest and apoptosis in L-1210 leukemia and ME-18 melanoma cells.  Oncol Rep.  10(6):2045-2050, 2003.

[6] Park, S. Y., et al.  Induction of apoptosis by isothiocyanate sulforaphane in human cervical carcinoma HeLa and hepatocarcinoma HepG2 cells through activation of caspase-3.  Oncol Rep.  18(1):181-187, 2007.

[7] Liang, H., et al.  Sulforaphane induces cell-cycle arrest and apoptosis in cultured human lung adenocarcinoma LTEP-A2 cells and retards growth of LTEP-A2 xenografts in vivo.  Journal of Natural Products.  2008.

[8] Misiewicz, I., et al.  Sulforaphane and 2-oxohexyl isothiocyanate induce cell growth arrest and apoptosis in L-1210 leukemia and ME-18 melanoma cells.  Oncol Rep.  10(6):2045-2050, 2003.

[9] Kim, J. H., et al.  Sulforaphane increases cyclin-dependent kinase inhibitor, p21 protein in human oral carcinoma cells and nude mouse animal model to induce G(2)/M cell cycle arrest.  J Clin Biochem Nutr.  46(1):60-67, 2010.

[10]Bryant, C. S., et al.  Sulforaphane induces cell cycle arrest by protecting RB-E2F-1 complex in epithelial ovarian cancer cells.  Mol Cancer.  9:47, 2010.

[11] Pham, N. A., et al.  The dietary isothiocyanate sulforaphane targets pathways of apoptosis, cell cycle arrest, and oxidative stress in human pancreatic cancer cells and inhibits tumor growth in severe combined immunodeficient mice.  Mol Cancer Ther.  3(10):1239-1248, 2004.

[12] Yao, H., et al.  Sulforaphane inhibited expression of hypoxia-inducible factor-1alpha in human tongue squamous cancer cells and prostate cancer cells.  Int J Cancer.  2008.

[13] Galan, M. V., et al.  Oral broccoli sprouts for the treatment of Helicobacter pylori infection:  a preliminary report.  Dig Dis Sci.  49(7-8):1088-1090, 2004.

[15] Cancer Epidemiology, Biomarkers & Prevention, 2005, 14(11).

Cancer Letters, 2006, 240:243–252.

Cancer Research, 2006, 66:8293–8296

Proc. Natl. Acad. Sci., USA, 2007, 104(44):17500-5.

[20] Fahey, J. W., t al.  Sulforaphane inhibits extracellular, intracellular, and antibiotic-resistant strains of Helicobacter pylori and prevents benzo[a]pyrene-induced stomach tumors.  Proc Natl Acad Sci USA.  99(11):7610-7615, 2002.

[22] Zhao, J., et al.  Sulforaphane reduces infarct volume following focal cerebral ischemia in rodents.  Neurosci Lett.  393(2-3):108-112, 2006.

[23] Murashima, M., et al.  Phase 1 study of multiple biomarkers for metabolism and oxidative stress after one-week intake of broccoli sprouts.  Biofactors.  22(1-4):271-275, 2004.

[27] Kong, J. S., et al.  Inhibition of synovial hyperplasia, rheumatoid T cell activation, and experimental arthritis in mice by sulforaphane, a naturally occurring isothiocyanate.  Arthritis Rheum.  62(1):159-170, 2010.

[28] Prochaska, H. J., et al.  Rapid detection of inducers of enzymes that protect against carcinogens.  Proceedings of the National Academy of Sciences USA.  89:2394-2398, 1992.

·Zhang, Y., et al.  A major inducer of anticarcinogenic protective enzymes from broccoli:  isolation and elucidations of structure.  Proceedings of the National Academy of Sciences USA.  89:2399-2403, 1992.

[29] Riedl, M. A., et al.  Oral sulforaphane increases Phase II antioxidant enzymes in the human upper airway.  Clinical Immunology.  130(3):244-251, 2009.

[31] http://dspace.biblioteca-innsz.org/bitstream/handle/123456789/12876/896D.pdf?sequence=1