Las Vegas — Indirect antioxidants offer a tremendous opportunity to take advantage of the body's endogenous antioxidant production capability, which allows it to protect against the development of cancer and signs of aging, says Rebecca James Gadberry, who spoke at the recent International Esthetics Cosmetics and Spa Conference here.
Ms. Gadberry is president of YG Laboratories, Huntington Beach, Calif., a company that manufactures high performance skin and body care products for prestige and medical brands. She explained to conference attendees that, unlike direct antioxidants which eliminate radical oxygen species by directly neutralizing them, indirect antioxidants act to increase the overall antioxidant capacity of cells. They promote the production of a variety of protective enzymes, including superoxide dismutase, catalase, and glutathione peroxidase, and so afford more comprehensive protection against more types of damage compared with the action provided by a single, direct antioxidant.
"Examples of direct antioxidants include vitamin C, vitamin E and beta-carotene. Their antioxidant activity has a limited lifespan. In contrast, the benefit of indirect antioxidants persists long after they have left the body because they serve to boost the sophisticated, natural antioxidant defense system. The indirect antioxidants provide a multilayered defense system, and their multifaceted level of action has been characterized as being equivalent to the force of an army of antioxidants," says Ms. Gadberry.
The indirect antioxidants are also thought to have a safety advantage compared with the direct antioxidants. There is evidence that various direct antioxidants may paradoxically increase cancer risk in certain situations by causing genetic damage. In contrast, there is less chance for those potential risks with indirect antioxidants, which are unlikely to become involved in oxidative reactions and act as "pro-oxidants" in the body, she explains.
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Research indicates that indirect antioxidants raise endogenous antioxidant levels via three separate mechanisms. First, they provide the chemical reactants (e.g., minerals) needed by the body for synthesis of the antioxidant enzymes. Second, many of them regenerate direct antioxidants to lengthen their lifespan. In addition, some can trigger the activity of a group of chemoprotective enzymes known as phase II detoxification enzymes.
"Associations between diet and decreased cancer risk have been linked to the effects of various dietary components on those latter enzymes," Ms. Gadberry says.
She reports that this new research on indirect antioxidants has potential implications for the performance skincare product industry as more manufacturers may aim to take advantage of the benefits of indirect antioxidants and develop novel formulations featuring those agents. However, various ingredients already found in some skincare products may provide indirect antioxidant activity.
Indirect antioxidants including various minerals and mineral derivatives, e.g., manganese, copper, zinc, selenium, and an extract of malachite (Malakite), as well as oligominerals, which contain those minerals attached to a pilot protein or oligopeptide for improved stability and delivery, can be found in a number of skincare products.
Examples of protein-linked minerals include copper peptides, zinc polypeptide complex, essential mineral oligoelement polypeptide complex, saccharomyces zinc ferment, saccharomyces copper ferment, saccharomyces manganese ferment, and saccharomyces germanium ferment.
PCA, a component of the skin's natural moisturizing factor, acts as a pilot molecule in zinc PCA, copper PCA and manganese PCA. Smithsonite extract (derived from a stone rich in zinc carbonate), and Malakite (an extract of malachite which is rich in copper) have also exhibited activity in boosting endogenous antioxidants.
"The latter agent was developed by the French company LIBiol/Gattefosse. Results from their in vitro studies show that at a 0.01 percent concentration of the malachite extract stimulated glutathione reductase in human keratinocytes by 30 percent compared with baseline," Ms. Gadberry notes.
Isothiocyanates, which is a family of compounds found in cruciferous vegetables, are also indirect antioxidants, and various extracts of those foods, including watercress, horseradish, wasabi, broccoli and mustard, are used in the formulation of some skincare products. Phenolic acids, especially ellagic acid, are also being looked at for their indirect antioxidant potential.