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.
FAQ: How do the levels of antioxidants in broccoli sprouts compare to other
foods / beverages with antioxidants?
What is the ORAC score for broccoli sprouts or SGS?
Answer: Neither BPP (nor the scientists at Johns Hopkins) have tested broccoli
sprouts or SGS extracts using the ORAC method
(Oxygen Radical Absorbance Capacity)
because we do not believe that it can properly measure the powerful,
persistent and prolonged phase 2 enzyme boosting activity and indirect
antioxidant capacity of sulforaphane and its pre-cursor glucosinolate
glucoraphanin (SGS™).
ORAC measures the ability of a substance to quench specific free radicals
at a specific single point in time in a laboratory (in vitro) test.
However, true antioxidant protection of cells and the body requires that
there is continuous and long-term capacity to detoxify damaging oxidants.
ORAC does not measure this ability over time and therefore simply does not
take into account whether a substance continues to provide activity and
protection after this single point. Indeed, ORAC is useful in measuring a
direct antioxidant where the neutralizing of free radicals is on a
one-to-one basis - where one molecule of the antioxidant usually detoxifies
one free radical and destroys itself in the process.
Such is not the case with the Phase 2 inducers which activate the
mechanism that boosts the ongoing activities of detoxifying enzymes in
the body for as long as several days.
In practice, most antioxidants such as Vitamin C found in orange juice,
polyphenols in tea and anthocyanins in blueberries are rapidly eliminated
from the body in just a few hours, whereas SGS stimulates the body to
protect for several days.
Thus, we feel that an ORAC measurement is simply not an adequate
representation of the antioxidant and health power of broccoli or broccoli
sprouts or their active components. Direct antioxidants (measured by ORAC)
are short-lived, self destruct during the protection process and require
continuous replenishment. Phase 2 inducers such as sulforaphane set in
motion a protective process that depends on the boosting of the body's
own protective enzymes. This protection persists, long after the sulforaphane
or SGS have left the body, because the enzymes continue to do their
protective work and are not used up in the process of protection.
References:
- Correlation
analyses of phytochemical composition, chemical, and cellular measures
of antioxidant activity of broccoli (Brassica oleracea L. Var. italica).
J Agric Food Chem 53: 7421-31.
Eberhardt, MV, Kobira, K, Keck, AS, Juvik, JA and Jeffery, EH, (2005)
- The chemistry behind antioxidant capacity assays.
J Agric Food Chem 53: 1841-56.
Huang, D, Ou, B and Prior, RL, (2005)
- NIGMS - 40 Years Of Discovery: From Molecules To Medicines
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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
SGS-specific Information
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