Chow_revised3.qxp 19/5/09 4:50 pm Page 50
Aesthetic Dermatology Cosmeceuticals
Figure 1: Diffuse Actinic Keratoses on Calf level.
3
Reactive oxygen species (ROS) are an innate part of the build-
up and break-down processes of the skin. Most oxygen in the body
is used at the cellular level through a series of electron transfers;
the molecular oxygen can become superoxide radicals that can
damage a cell’s lipids, proteins and DNA. Enzymes in our cells
control these processes, preventing oxidative damage to the cells.
However, radiation from the sun, smoking and pollution may
overpower the body’s inherent protective mechanisms and cause
oxidative cancerous changes. Hence, topical antioxidant is a
necessity in the post-medical treatment of AKs.
It has been well established that sunscreen works by preventing the
penetration of harmful UV rays into the skin. However, studies have
shown that sunscreen itself can prevent only 40–50% of UVA and
UVB rays from penetrating the epidermis. Sunscreen protection is
user-dependent, relying on careful application. Sweating, rubbing
and degradation in sunlight can easily remove sunscreen from the
Figure 2: Actinic Keratosis Lesion
skin. In actual usage, individuals apply only 20–25% of the amount
needed to achieve the sun protection factor (SPF) advertised.
4
Other
studies have also shown that significant free-radical generation by
UV radiation occurs even when the skin is protected by sunscreen.
5
Even the best sunscreens protect against only 45–55% of free
radicals generated by routine sun exposure.
6
These facts further
support the importance of using a topical antioxidant once daily to
cover the remaining 45–55% of daily environmental damage that
sunscreen cannot prevent.
Particular attention has been given to a topical antioxidant serum
containing vitamin C and E stabilised by ferulic acid (Skinceuticals
CE Ferulic), a highly stable formulation that can penetrate the skin.
This combination offers photoprotective effects including reduction
of the following: erythema, sunburn cell formation, carcinogenic
DNA changes (such as thymine dimers), UV immunosuppression
and, subsequently, reduction of AK, skin cancer and photoageing.
The CE Ferulic product contains two major components: vitamin C
and vitamin E. Vitamin C is a major free-radical scavenger and works
in the aqueous phase of the human body.
7
It provides protection
against photoageing, as it is essential for collagen biosynthesis. It
also inhibits elastase, an enzyme that occurs in photodamaged
skin.
8
It can also reduce hyperpigmentation by inhibiting tyrosinase.
9
Figure 3: Squamous Cell Carcinoma on Dorsum of Hand
Vitamin E, another major antioxidant, works in the body’s lipid
phase. Its major function is to prevent lipid peroxidation, which may
threaten the structural integrity of cell membranes. After vitamin E
removes a free radical, it can be regenerated back to its ‘active’
reduced form by vitamin C, thus demonstrating a dependent
relationship between these two components of the topical
antioxidant serum CE Ferulic (see Figures 4 and 5). Ferulic acid is a
natural plant antioxidant and provides chemical stability to vitamins
C and E and increases its photoprotective properties.
10
The addition of phloretin to antioxidant formulations has gained
significant attention recently. Phloretin is a natural potent
antioxidant found uniquely in the flesh and skin of apples. In several
studies, phloretin has been shown to have strong antioxidant effects
when tested against free radicals and hydroxyl radicals and in the
prevention of lipid peroxidation.
11
Phloretin has also been shown to
inhibit matrix metalloproteinase-1 (MMP-1) and elastase,
12
enzymes
photodamage and pre-cancerous changes such as AKs, as that degrade connective tissue and cause photoageing. Just like
previously mentioned. Photoageing includes wrinkling, dryness, vitamin C, phloretin can also inhibit tyrosinase and, subsequently,
uneven pigmentation and a decrease of collagen on a molecular reduce hyperpigmentation. As an additional benefit, phloretin
50 EUROPEAN DERMATOLOGY
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