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The Science Behind Today’s Anti-aging Ingredients
By: Ivana Veljkovic
Posted: December 30, 2011, from the January 2012 issue of Skin Inc. magazine.
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Recently, research into using stem cells—both human and plant-based—in cosmeceuticals has increased. To understand why this category of ingredients is compelling to the skin care industry, first you must elucidate how stem cells benefit the skin. The role of cutaneous stem cells is to replenish skin as it undergoes normal functions and wound repair. The majority of these cells reside in the basal layer of the epidermis. When a stem cell divides, the daughter cells have the potential to either remain a stem cell, like the parent cell, or to differentiate into cells with a more specialized function, known as progenitor cells. As people age and with environmental damage, the ability for stem cells to repair skin becomes diminished. Supplementing the skin with additional stem cells is an obvious solution. But, there are numerous ethical and formulation issues in using human embryonic stem cells in cosmeceuticals. Science naturally turned to plants.
Unlike human stem cells that can differentiate only into another type of cell, plant-derived stem cells are intriguing, because they are totipotent—they have the ability to create an entirely new plant. The role of most of these plant-derived ingredients is to protect existing human stem cells residing in the basal layer of human skin from DNA damage due to multiple radical species. In recent years, researchers have identified naturally occurring botanicals with substantial antioxidant activity proven to help protect skin stem cells from this UV-induced oxidative stress, inhibit inflammation, neutralize free radicals and reverse the effects of photoaging. Consequently, cosmeceutical products containing extracts derived from plant stem cells have the ability to promote healthy cell proliferation and protect against UV-induced cellular damage in humans. Although there are potentially many botanical stem cells that could provide benefits to the skin, the bulk of research has been focused on three rich sources of phyto stem cells: grape, lilac and Swiss apple.
Grape seed extract. Probably the most widely and longest studied botanical is the Vitis vinifera (grape) seed extract. Decades of research suggest that grape seeds provide anti-inflammatory properties, help prevent skin aging, scavenge radical oxygen species and inhibit UV radiation-induced damage. Proanthocyanidins—a group of polyphenolic bioflavonoids found in grape seeds and their stem cells—are responsible for its powerful antioxidant effect and its anti-tumor activity. They have also demonstrated the ability to protect the skin’s own endogenous antioxidant mechanism, providing superior radical-quenching. Grape-derived stem cells are beneficial additives to any skin care formulation due to their protective effects.
Lilac leaf. Verbascocides, from the stem cells of Syringe vulgaris (lilac) leaf, have demonstrated not only potent radical-quenching action and matrix metalloproteinase inhibitor (MMPi) activity, but also the ability to repair dAMP hydroxyl adducts following DNA damage. When studied, verbascosides demonstrated the ability to significantly speed wound-healing and deliver potent anti-inflammatory action. These benefits were thought to be due to its ability to inhibit the release of radical oxygen species by recruiting proinflammatory cells to the damaged skin. In fact, the verbascoside-containing extracts demonstrated superior efficacy than both hydrocortisone and triamcinolone in inhibiting inflammation.
Swiss apple. With newer upcoming ingredients, often the only available research is that of the ingredient’s manufacturer. This can be well-performed science, but the obvious conflict of interest must be taken into consideration. An ingredient manufacturer’s study showed that a 0.1% concentration of stem cells extracted from Swiss apples stimulated the proliferation of human stem cells by 80%. In a trial with 20 subjects, a cream containing the apple extract was found to reduce wrinkle depth by 8% after two weeks and 15% after four weeks. Similarly, a cream and serum containing stem cells extracted from the edelweiss plant, which has been investigated for its anti-inflammatory properties, is reported to reduce wrinkle depth. Additional peer-reviewed studies are needed to substantiate these claims.