| Nutrition / Plants and plant products |
Sulforaphane, a powerful phytochemical
Among other things, some plants contain in their cells two physically separated chemicals: myrosinase and glucosinolates. When plant cells are damaged (insects, cattle, humans), the two chemicals are released and come in contact, resulting sulforaphane (SFN) that has a pungent taste, that may repel predators… human included.
SFN is a defense mechanism for plans, but has mostly health-promoting properties for humans.
It exhibits chemoprotective and chemotherapeutic mechanisms in cancer cells, may improve hypertensive states, prevent type 2 diabetes–induced cardiomyopathy, protect against gastric ulcer, may help in schizophrenia treatment, and obesity.
The mechanism underlying the health-promoting effect of SFN relates to its antioxidant and detoxifying effects.
Clinical trials suggest that sulforaphane produces favorable results in cases where pharmaceutical products fail. SFN exhibits the highest bioavailability among well-known antioxidant phytochemicals, such as quercetin and curcumin.
Sulforaphane creation process.1
Cruciferous plants have a high content of SFN and when chopped during the food preparation process, glucosinolates (SFN precursors) are rapidly hydrolyzed by the myrosinase enzyme, generating metabolites that are then absorbed in the intestine.
In contrast, cooking cruciferous vegetables before consumption inactivates myrosinase, thus preventing the conversion of glucosinolates to SFN. However, lightly cooking (i.e., light steam for less than five minutes) will preserve some of the myrosinase and allow for isothiocyanate conversion.
A small fraction of intact glucosinolates may be absorbed in the small intestine, but a large proportion reaches the colon. In the colon, myrosinase produced by the microbiota can catalyze the generation of a wide range of metabolites from glucosinolates, depending on the pH and the presence of other cofactors.
Table 1: Glucosinolates (SFN precursors) content in mg / 50g of food
| Food | mg/50g |
| Garden cress | 196 |
| Mustard greens | 141 |
| Brussels sprouts | 118 |
| Horseradish | 80 |
| Kale | 50 |
| Watercress | 47 |
| Turnip | 46 |
| Cabbage, savoy | 39 |
| Cabbage, red | 32 |
| Broccoli | 31 |
| Bok choy (pak choi) | 27 |
| Kohlrabi | 23 |
| Cauliflower | 22 |
Three-day-old sprouts of cultivars of certain crucifers including broccoli and cauliflower contain 10–100 times higher levels of glucoraphanin (the glucosinolate of sulforaphane) than do the corresponding mature plants.
In 1994 scientists found a key factor in our cells called Nrf22.
They found that plants contain special chemicals (phytochemicals) that can turn on Nrf2. When Nrf2 is activated, it helps protect our cells by turning on a lot of defense genes at once.
The ability of sulforaphane to activate Nrf2 is 105 times of resveratrol, 18 times of silymarin, 13.5 times of curcumin and quercetin,3 and more than 250 times of the vitamin C.
A daily dose of 20-40 mg of SFN has been found to have positive effects in clinical trials.
Sources
• www.mdpi.com/1420-3049/26/3/752
• www.ncbi.nlm.nih.gov
• https://europepmc.org/article/PMC/4736808
• https://lpi.oregonstate.edu/mic/dietary-factors/phytochemicals/isothiocyanates
• https://en.wikipedia.org/
Footnotes
1. The addition of radish, rocket and rape sprouts to broccoli sprouts could promote the hydrolysis of the glucoraphanin to the biologically active sulforaphane (instead to the inert form) to 2.03, 2.32 and 1.95-fold, respectively, compared to single broccoli sprouts. Brief heating is also shown to increase the production of the active form of SFN.
2. Nrf2 stands for Nuclear factor erythroid 2-related factor 2. It is a transcription factor, a protein that plays a crucial role in regulating the expression of various genes involved in the body's defense mechanisms against oxidative stress and inflammation.
Nrf2 is known for its role in promoting the expression of antioxidant and detoxification genes, which help protect cells from damage caused by free radicals and other harmful substances.
3. Resveratrol is a type of natural phenol produced by several plants in response to injury or when the plant is under attack by pathogens, such as bacteria or fungi. Sources of resveratrol in food include the skin of grapes, blueberries, raspberries, mulberries, and peanuts.
Silymarin is an extract from the dried seeds and fruits of the milk thistle plant (S. marianum). Milk thistle has been used medicinally in Europe since the first century AD.
Curcumin is a biologically active polyphenolic compound found in turmeric, a spice derived from the rhizomes of the plant Curcuma Longa.
Quercetin is a plant flavonol from the flavonoid group of polyphenols. It is found in many fruits, vegetables, leaves, seeds, and grains; capers, red onions, and kale are common foods containing appreciable amounts of it.
YOU MAY ALSO LIKE
