All About Antioxidants

The term “antioxidant” is frequently used in conjunction with nutrition, cancer prevention, and anti-aging strategies.  Oxidative cell damage is assumed to be a factor in cancer, aging, and many chronic diseases.  Antioxidants help prevent oxidation, may increase immune responses, and possibly decrease risk of infection and cancer.

·        Antioxidants are vitamins, minerals, or phytochemicals (plant chemicals) that are capable of neutralizing free radical molecules, making them less reactive.

·        Free radicals are molecules or atoms found in living cells that have at least one unpaired electron, making them unstable and highly reactive in the cell.

What causes free radical damage?

·        Free radicals can be caused by expending high levels of energy, exposure to radiation, toxic chemicals or environmental pollutants, food/diet and inadequate dietary intake of antioxidants.

·        Free radicals are normally held in balance by the body’s antioxidant defense system, but with an excessive amount of free radicals, oxidative cell damage can occur.

·        Free radical activity can cause cell membranes to leak, DNA to miscode, or enzyme proteins to cease functioning.

A diet that includes antioxidant rich fruits and vegetables is, according to research, an effective way to counteract oxidation or free radical damage.  How? The antioxidants contained in fruits and vegetables work in concert with the body’s enzymes to neutralize free radicals.   Enzymes speed up the chemical reactions in our bodies, enabling us to think, move, digest food, and perform many other daily activities.(1)

Direct and Indirect Antioxidants:

Antioxidants can be either direct or indirect in their effects on free radicals.

·        Direct antioxidants, like vitamins E, C, and beta-carotene, neutralize only one free radical molecule at a time, and are consumed in the process. 

·        Direct antioxidants work together with Phase I enzymes to activate or deactivate oxidants.

·        Indirect antioxidants induce or boost the activity of the Phase 2 enzymes, which detoxify free radicals. These enzymes act as a defense mechanism, triggering broad spectrum antioxidant activity that neutralizes many free radicals (4).

·        The indirect antioxidant effects are long-lasting, triggering an ongoing process that may last for days.

 SGS™ : An Indirect Antioxidant

In 1992, Dr. Paul Talalay and his research team isolated and identified sulforaphane, a phytochemical whose precursor, sulforaphane glucosinolate, exists in cruciferous vegetables such as broccoli and cabbage.  Evidence suggests that sulforaphane functions as an indirect antioxidant (2), capable of neutralizing many free radicals at a time, for long periods of time.

After a decade of research at Johns Hopkins University and other laboratories around the world, results confirm that sulforaphane has potential cancer preventative effects (2-15).  The Johns Hopkins University researchers and Brassica Protection Products LLC continue to focus on sulforaphane and other phytochemicals that may protect health and prevent cancer.

References: 

1.      www.nigms.nih.gov/anniversary/discovery/index-noscript.html

2.      Prochaska HJ, Santamaria AB, and Talalay P.  Rapid detection of inducers of enzymes that protect against carcinogens. Proc Natl Acad Sci USA 1992 Mar 15;89(6):2394-8.

3.      Fahey J, Zhang Y, Talalay P.  Broccoli sprouts: An exceptionally rich source of inducers of enzymes that protect against chemical carcinogens.    Proc. Natl Acad Sci USA 1997 Vol 94, pp. 10367-10372.

4.      Fahey J, Talalay P.  Antioxidant functions of sulforaphane: a potent inducer of Phase II detoxication enzymes.  Food Chem Toxicol 1999 Sep-Oct;37(9-10):973-9.

5.      Zhang Y, Kensler TW, Cho C, Posner GH and Talalay P. Anticarcinogenic activities of sulforaphane and structurally related synthetic norbornyl isothiocyanates Proc Natl Acad Sci USA 1994 Apr 12;91(8):3147-50 .6.

6.      Singletary K, MacDonald C.  Inhibition of benzo[a]pyrene- and 1,6-dinitropyrene-DNA adduct formation in human mammary epithelial cells by dibenzoylmethane and sulforaphane.  Cancer Letters, July 3, 2000; 155(1):47-54.

7.      Gamet-Payrastre L, Li P, Lumeau S, Cassar G, Dupont MA, Chevolleau S, Gase N, Tulliez J, Terçé F. Sulforaphane, A Naturally Occurring Isothiocyanate, Induces Cell Cycle Arrest and Apoptosis in HT29 Human Colon Cancer Cells.  Cancer Research, March 1, 2000; 60(5):1426-1433.

8.      Wu L; Juurlink BHJ.  The impaired glutathione system and its up-regulation by sulforaphane in vascular smooth muscle cells from spontaneously hypertensive rats. Hypertension, 2001; 19:1819-1825.

9.      Brooks JD, Paton VG, and Vidanes G.  Potent induction of Phase 2 enzymes in human prostate cells by sulforaphane.  Cancer Epidemiology, Biomarkers & Prevention, Sept. 2001; 10:949-954.

10. Fahey J, Haristov X, Dolan P, Kensler T, Scholtus I, Stephenson K, Talalay P, Lozniewski A.  Sulforaphane inhibits extracellular, intracellular, and antibiotic-resistant strains of Helicobacter pylori and prevents benzo[a]pyrene-induced stomach tumors.  Proc. Natl. Acad. Sci. USA, Vol. 99, Issue 11, pp. 7610-7615, May 28, 2002.

11.Gao X, Dinkova-Kostova A, Talalay P. Powerful and prolonged protection of human retinal pigment epithelial cells, keratinocytes, and mouse leukemia cells against oxidative damage: the indirect antioxidant effects of sulforaphane. Proc. Natl. Acad. Sci. USA, Vol. 98, Issue 26, pp. 15221-15226, December 18, 2001.

12.Ramos-Gomez M, Kwak M, Dolan P, Itoh K, Yamamoto M, Talalay P,  Kensler T.  Sensitivity to carcinogenesis is increased and chemoprotective efficacy of enzyme inducers is lost in nrf2 transcription factor-deficient mice.
Proc. Natl. Acad. Sci. USA, Vol. 98, Issue 6, 3410-3415, March 13, 2001. 

13.Dinkova-Kostova A, Massiah M, Bozak R, Hicks R, Talalay P. Potency of Michael reaction acceptors as inducers of enzymes that protect against carcinogenesis depends on their reactivity with sulfhydryl groups. Proc. Natl. Acad. Sci. USA, Vol. 98, Issue 6, 3404-3409, March 13, 2001.

14.Chung F-L, Conaway CC, Rao CV, Reddy BS.  Chemoprevention of colonic aberrant crypt foci in Fischer rats by major isothiocyanates in watercress and broccoli.  Proceedings of the American Association for Cancer Research, March 2000; 41:660.

15.Talalay, P. The war against cancer: New hope.  Proceedings of the American Philosophical Society, March 1999, Vol. 143(1), pp. 52-72.

General Antioxidant Information

• More News On The Supplement Front: Cancer & Antioxidants
• http://www.goaskalice.columbia.edu/0830.html
• www.nlm.nih.gov/medlineplus/antioxidants.html
• http://www.eatright.org/ermprev.html

SGS-specific Information

• SGS (Sulforaphane Glucosinolate) Fact Sheet
• Research Summary: A Look at Sulforaphane Glucosinolate (SGS) and Preliminary Evidence for Its Role in Reducing Risk of Cancer
• New Research Finds Antioxidant Found in BroccoSprouts May Have Even More Benefits