SIGNS OF AGING
Silab researchers explain how by acting on the endogenous hyaluronic acid pathway.
Pauline Rouaud-Tinguely, David Boudier, Sylvain Mazalrey, Jenny Laumonier, Isabelle Cruz, Géraldine Bon,
Karine Perrinet, Béranger Tassy, Brigitte Closs •Silab R&D, Saint-Viance, France.
HYALURONIC ACID is the most abundant skin component and, in conjunction with collagen and elastin, consti- tutes the dermal support tissue. Due to its high hygroscopic capacity, it has the ability to capture and bind a significant
quantity of water.1 In the form of a hydrated gel, it replenishes
interstitial spaces between the fibrillar components of the extracellular matrix, thus guaranteeing skin hydration as well as
the maintenance of its suppleness.2-4 Hyaluronic acid is a non-sulfated glycosaminoglycan with rapid metabolic turnover. Its
synthesis is ensured by hyaluronan synthases (HAS1, HAS2 and
HAS3) and its degradation by hyaluronidases (HYAL). 5 Among
the enzymes involved in its synthesis, HAS2 is the only one resulting in high molecular weight hyaluronic acid production in
the depth of the skin.
In the course of aging, the dermal content of hyaluronic acid
diminishes, due to the reduced expression of its synthesis en-
zymes by dermal fibroblasts. 6 These age-related metabolic chang-
es directly affect the skin’s water content and therefore promote
the loss of its elasticity and the appearance of wrinkles. 7-8 This
explains why boosting the presence of hyaluronic acid to take up
and retain water in the skin is an essential factor for the efficacy
of skin-moisturizing and/or anti-aging concepts.
Among products on the market, the topical application of hy-
aluronic acid is one of the approaches currently used in cosmet-
ics. Their effectiveness is nevertheless closely linked to the sizes,
structures and origins of hyaluronic acid applied to the skin.
The logical strategy would therefore be to simply boost the
skin’s natural capacities to make up the shortfall of its intrinsic
hyaluronic acid content. In line with this objective, Silab has developed an exclusive natural active ingredient, Prohyal+ (INCI:
Yeast extract). This active ingredient is obtained from the yeast
Metschnikowia agaves, a microorganism found in the Mexican
blue agave ecosystem. 9 Just as the agave has developed an efficient strategy to retain water in a very arid environment, YE is a
biomimetic active ingredient that reactivates the natural mechanisms of hyaluronic acid synthesis in order to take up and retain
water in the skin. This efficacy was evaluated in vitro and in vivo
and was compared to reference molecules.
Figure 1: Effect of YE tested at 2% on the endogenous production of hyaluronic acid by normal human fibroblasts