Virginie Anchartechahar, Elsa Hernandez
2018, 30th IFSCC congress
Introduction
Our skin is continually under stress resulting in accelerated aging. These stresses come from external pollution such as blue light, smoke or hydrocarbons, or internal stresses leading to insufficient autophagy and energetic metabolism. The involvement of UV radiation in the generation of free Reactive Oxygen Species (ROS) has been widely described. Excessive blue light exposure also accelerates the oxidation process, inducing ROS formation [1] and stimulates the keratinocytes differentiation [2]. These ROS affect not only the normal lysosomes network but also the normal filament-like structure of the mitochondria network. HCR extract is a concentrated extract of sugars from the rhizomes of Hedychium coronarium, an original malagasy plant. Seppic investigated its specific biological mechanism with a specific focus on mitochondria protection, autophagic activity on lysosomes and finally assessed its skin protective effect through a clinical study in a polluted environment.
Methods and results
In vitro studies
Oxidative stress is one of factors responsible for skin ageing and inflammatory reactions generated by internal and external aggressions. The antioxidant potential of HCR extract on ROS has been challenged in normal human keratinocytes stressed with polluant 3,4-benzopyren (BaP) at 36 µm. Detection was performed with a fluorescent probe (dichlorodihydrofluoresceine diacetate) at 490 nm (excitation) and 525 nm (emission). HCR extract at 0.5% permits to decrease the ROS liberation of 23% induced by BaP polluant in keratinocytes. Mitochondria are small organelles producing cell energy through respiration and regulating cellular metabolism. HCR extract effect on mitochondrial metabolic activity (ATP and NAD+/NADH) and network (in vitrogen Mito tracker staining) has been studied in fibroblasts irradiated with UVA rays. HCR extract at 0.5% stimulates significatively ATP production (+136%) and NAD+/NADH (+19%). Visual analysis of mitochondria shows a protection of the network against UVA irradiations. Lysosomes are cytoplasmic organelles recycling cellular material (digestion also called autophagy). HCR extract action on autophagic activity (Monodansylcadaverin probe) and lysosomal network (Lyso Tracker staining) was studied in fibroblasts irradiated with blue light. At 0.5%, HCR extract regulates of 35% the autophagic activity and protects the lysosomal network. In vivo study HCR extract has been tested at 3% versus placebo during 28 days on two groups of 20 urban women from 45 to 55 years old (caucasian skin), smokers, stressed. Clinical face scoring (scale 0 to 9) at D0 & D28 and self evaluation questionnaires at D28. Luminosity significantly increases by 40% after 28 days (versus D0) with HCR extract whereas only 24% increase is observed for placebo in the same conditions. Self evaluations with HRC extract conclude on several skin benefits: luminous, moisturized, homogeneous, more radiant complexion.
Conclusion
HCR extract acts as a multiprotector against pollution and internal stresses generated by UVA and blue light irradiation. HCR extract reduces oxidative stress efficiently. In presence of UVA irradiation HCR extract maintains the mitochondria network and energetic activity. In presence of blue light rays, HCR extract protects the lysosomal network and regulates autophagy activity thanks to a barrier effect [3]. Thanks to these multiple protections, the skin is visibly more luminous, in vivo.
[1] Lohan, S.B., et al., 2016, Exp. Dermatol., 25, 380
[2] Liebmann J. et al., 2010, J. Invest. Dermatol., 130, 259
[3] Zaho Y et al., 2013, J.Invest.Dermatol., 133(6) : 1629-37
Seppic, 22 Terrasse Bellini - Paris La Défense, 92800 Puteaux, France