Labskin-S 3D in vitro human skin equivalent was populated with a whole skin microbiome sample donated by a volunteer presenting with adult acne post-pregnancy. The microbiome sample was allowed to establish and proliferate on the surface of the Labskin-S. Test items were applied to the microbiome-skin constructs including a 5% benzoyl peroxide product, a 2% succinic acid product and a DPS control.  The results showed that the 2% succinic acid product was most effective in reducing the C.acnes present in the skin microbiome, but that it also elicited the greatest inflammatory response. The study highlights the importance of evaluating microbiome modulating products in a skin equivalent model, not just to measure the effectiveness of microbe reduction but also the skin inflammatory responses.

This study investigated sebocyte differentiation and lipid metabolism in acne vulgaris using the SEBO662AR cell line, a physiologically relevant in vitro model characterized by stable expression of a functional androgen receptor. The research aimed to evaluate its utility as a tool for advanced skin care testing.
Acne vulgaris is associated with irregular sebum production influenced by hormonal fluctuations, changes in the microbiome, and dietary factors. The study employed a differentiation mixture (Diff Mix) to simulate these imbalances and analyzed gene expression and lipid synthesis. The results revealed significant changes in gene expression related to sebocytes, as well as a notable increase in squalene accumulation, indicating the functionality of squalene epoxidase (SQLE). Importantly, the alterations induced by Diff Mix were reversible with specific inhibitors.
This work highlights the SEBO662AR cell line's value as a model for acne-related research. By modeling pathological sebum production, it serves as a suitable platform for studying lipid synthesis mechanisms, offering significant potential for skin care testing and product development targeting sebaceous activity.

Cabannes Magalie1*, Piccirilli Antoine2 Dr Berthon Jean-Yves1, Francolon Romain1
1 Greentech SA Biôpole Clermont Limagne 63360 Saint Beauzire, France,
2 La Fabrique Végétale ,18 chemin de Tisson 86000 Poitiers, France,

Synthetic silicones such as dimethicones, while valued for their smooth sensory and emollient
properties, raise concerns due to their poor degradability and potential environmental
accumulation. That is why, in the search of more sustainable and biocompatible formulations,
there is a growing demand for natural alternatives to dimethicones. The objective of that study
was thus to fill these gaps developing an effective natural substitute to mimic, or at least
approach, soft and emollient properties of dimethicones. Our interest focused thus on a novel
semi-solid oil derived from avocado, specifically enriched in palmitic acid, which exhibits
unique physico-chemical and functional properties suitable for use in dermatological and
cosmetic compositions. A specific process of extraction, purification, and enrichment of fatty
substances from the unsaponifiable fraction of avocado oil was used, resulting in the obtention
of a stable, semi-solid lipid product (called here SSL) with high content of saturated fatty acids,
as palmitic acid. Characterization of the semi-solid oil polymorphism with gas chromatography
and differential scanning calorimetry (DSC), confirmed its fatty acid composition (C16:O
Palmitic acid 35-45%, Palmitoleic acid 3-10% omega-7, C18:1 Oleic acid 40-60% omega-9,
C18:2 Linoleic acid 5-15% omega-6); melting behavior, and oxidative stability (98°C, 23h,
Rancimat test; ISO EN 6886). Of interest, developed product SSL has a melting point higher
than conventional avocado oil (45-55°C), making it ideal for structuring formulations. Its semisolid
nature enables it to act as a structuring agent, improving sensory feel and mechanical
stability without requiring synthetic waxes or petroleum-based agents (silicones, paraffin oil).
Different studies were also conducted with SSL at 5 to 15% vs reference products such as
paraffin oil substitute, dimethicone or avocado oil to assess its functional properties. These
studies revealed a similar rheological behavior than paraffin with a visually richer aspect and
without soaping effect. Another experiment was performed with SSL 5 % vs 5% dimethicone
on 20 volunteers from 22 to 54 years old. Panelists described similar products in term of
softness, richness, feeling and nourishing effect on skin. Also, a moisturizing test was
performed on 10 volunteers using a Corneometer® CM825 after a single application of an
emulsion containing SSL 20% or paraffin oil 20%. A comparative effect was observed between
both products after one hour, three hours and seven hours. Finally, an ex vivo study conducted
on damaged strands hair revealed significant results (*p<0,05) with SSL on hair suppleness
(+25%), hair softness (+25%) and hair nourishing (26%) contrary to classical avocado oil.
These properties are related to its high content in palmitic acid. This study allows thus the
development of a natural upcycled alternative to dimethicones showing comparable soft touch
associated with strong emollient properties related to palmitic acid content. To complete theses
researches, a proteomic study in on going with SSL 5% on skin explants vs placebo in order to
get an exhaustive vision of complementary skin biological properties. These researches provide
a novel functional ingredient from avocado, rich in palmitic acid, with sensory, stabilizing
properties in cosmetics skin and hair care.
Keywords: Super emollient, silicone alternative