SKINIPEDIA - Skin Encyclopedia: Protecting Skin

Protecting Skin with Antioxidants (Part 4)

Green tea

Camellia sinensis is a rich source of polyphenols, which are produced during the processing of the tea leaf. Green tea includes six polyphenol catechins, including epigallocatechin-3-gallate (EGCG). Topical application of green tea
polyphenols on humans has demonstrated that it protects the skin against UV-induced erythema and inflammation. Studies with mice have shown EGCG to prevent photocarcinogenesis, a decrease in collagen degradation, and oxidative stress in tissues. There are reports that green tea extracts are 200 times more powerful than vitamin E (tocopherol) and that they
may increase the activity of certain antioxidant enzymes found in the skin, most notably, glutathione peroxidase, which scavenges lipid peroxidase radicals that attack cell membranes.

Soy flavonoids

Soy isoflavonoids have antioxidant, anticancer and estrogen-like properties. The two major soy isoflavonoids are genistin and daidzin—both sugar derivatives that must be hydrolyzed in the gut to release their active aglycone flavonoids,
genistein and daidzein. Studies using the aglycones topically on the skin of menopausal women have shown these flavonoids to be beneficial in treating aging and photoaging conditions as well as offer photoprotective properties.

Rooibos extract

Extracts from the red bush grown only in the Cederburg Mountain region of South Africa have demonstrated that this unique bush contains flavonols with powerful antioxidant properties. It has been reported that the flavonols found
in red bush mimic the activity of superoxide dismutase. While its use has been somewhat restricted to South Africa, it has been used to treat skin conditions including eczema, acne and dermatitis. This antioxidant extract will undoubtedly be used in more products as formulators are made aware of its benefits to the skin.

Superoxide dismutase

Known as SOD, superoxide dismutase is an enzyme found naturally in the body. It is the most effective means to control a reactive oxygen species known as superoxide that can destroy tissue in the body. SOD initiates and catalyzes the binding of protons to the superoxide anion forming peroxide, which is subsequently destroyed by the peroxidase enzyme, thus avoiding the lethal hydroxyl radical from forming. Unfortunately, SOD is a very expensive ingredient and hence, few manufacturers can afford to use it in their formulas.

Antioxidant cocktails

We know that oxidative stress plays a key role in the biological events leading to the signs of aging in our skin. Antioxidant use may help to prevent future damage as they trap reactive oxygen species and quench them before they damage our cells. The use of antioxidant cocktails or combinations of free- radical scavengers may prove to be most beneficial in the prevention and treatment of skin photoaging—our best defensive line.

Article by Diana L. Howard, Ph.D., the vice president of technical development for Dermalogica and The International
Dermal Institute. Call her at 1-(800) 611-SKIN or visit http://www.dermalogica.com/professional.