Neryl acetate, the major component of Corsican Helichrysum Italicum essential oil mediates its activity
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Presented by: Geraldine Lemaire
Helichrysum Italicum (Roth) G. Don subsp. Italicum from the Asteracea family grows on dry, rocky or sandy ground around the Mediterranean basin and is commonly known as the everlasting plant. Helichrysum italicum essential oil (HIEO) is obtained from the hydrodistillation of aerial parts and its composition is known to depend on the geographical area of collection. Indeed, the chemical composition of the essential oils of Helichrysum Italicum collected in Sicily and Corsica shows that the Sicilian oils are rich in α- and β-selinene, rosifoliol and aromadendrene whereas the Corsican oils are rich in neryl acetate (NA, 33.7-38.9%), and contain also neryl propionate (3.4–5.9%) and β-diketones (total content 4.8–9.4%).
NA is an acetate ester resulting from the formal condensation of the hydroxy group of nerol with the carboxy group of acetic acid. This volatile metabolite of the plant participates to its fragrance, but no biological activity of NA is described.
The stratum corneum provides the body’s main barrier to the environment and is key to maintaining optimal cutaneous hydration. During aging, the skin barrier function is reduced and the composition of the CE changes dramatically due to altered expression patterns of genes coding for major components of the CE. There is also an overall reduction of stratum corneum lipids and a disturbance regarding the cholesterol and fatty acids synthesis. Cer[EOS] is significantly reduced in seniors (>50 years) compared to younger individuals (20-40 years). Moreover, the degree of fatty acid chain saturation of Cer[EOS], which has marked effects on lamellar and lateral lipid organization, is decreased in autumn and winter, partially accounting for worse barrier function. Consequently, there is also evidence of altered permeability barrier to chemical substances and increased trans-epidermal water flux in aged skin.
We previously demonstrated that a 24 hours treatment with Corsican HIEO increases the expression of genes part of the differentiation complex (IVL, SPRRs, LCEs, S100-family) in skin explants.
NA, as part component of HIEO, was tested on skin explant model during 24 hours and 5 days compared to HIEO. We analyzed the biological regulations in the skin explant by transcriptomic analysis, skin barrier protein immunofluorescence, lipid staining and ceramides analysis by LC/MS.
Transcriptomic analysis revealed that 43% of HIEO modulated genes are also regulated by NA; those genes are related to skin barrier formation (keratinocyte differentiation, epidermal differentiation complex, and junctions) and ceramides synthesis. We focused on involucrin that is upregulated at both gene and protein levels by treatments. Total lipids and ceramides were also increased and this was correlated with genes involved in lipid and ceramide synthesis pathways. Those results demonstrated in our experimental conditions that NA mediated skin barrier formation induced by Corsican HIEO.
In conclusion, our results demonstrate that NA, the major component of HIEO, reinforced the skin barrier function by increasing lipids and ceramide content in the SC by enhancing the expressions of ceramide synthesis-related enzymes required for the glucosylceramide pathway. Furthermore, both compounds increased epidermal differentiation by stimulating the expression of IVL (transcript and protein). In addition, we demonstrated for the first time that HIEO-regulated effects in this study are mediated by its principal component, neryl acetate. Therefore, we anticipate that Neryl acetate may be effective in improving skin barrier function and moisture retention in skin conditions with altered barrier such as aging.
NA is an acetate ester resulting from the formal condensation of the hydroxy group of nerol with the carboxy group of acetic acid. This volatile metabolite of the plant participates to its fragrance, but no biological activity of NA is described.
The stratum corneum provides the body’s main barrier to the environment and is key to maintaining optimal cutaneous hydration. During aging, the skin barrier function is reduced and the composition of the CE changes dramatically due to altered expression patterns of genes coding for major components of the CE. There is also an overall reduction of stratum corneum lipids and a disturbance regarding the cholesterol and fatty acids synthesis. Cer[EOS] is significantly reduced in seniors (>50 years) compared to younger individuals (20-40 years). Moreover, the degree of fatty acid chain saturation of Cer[EOS], which has marked effects on lamellar and lateral lipid organization, is decreased in autumn and winter, partially accounting for worse barrier function. Consequently, there is also evidence of altered permeability barrier to chemical substances and increased trans-epidermal water flux in aged skin.
We previously demonstrated that a 24 hours treatment with Corsican HIEO increases the expression of genes part of the differentiation complex (IVL, SPRRs, LCEs, S100-family) in skin explants.
NA, as part component of HIEO, was tested on skin explant model during 24 hours and 5 days compared to HIEO. We analyzed the biological regulations in the skin explant by transcriptomic analysis, skin barrier protein immunofluorescence, lipid staining and ceramides analysis by LC/MS.
Transcriptomic analysis revealed that 43% of HIEO modulated genes are also regulated by NA; those genes are related to skin barrier formation (keratinocyte differentiation, epidermal differentiation complex, and junctions) and ceramides synthesis. We focused on involucrin that is upregulated at both gene and protein levels by treatments. Total lipids and ceramides were also increased and this was correlated with genes involved in lipid and ceramide synthesis pathways. Those results demonstrated in our experimental conditions that NA mediated skin barrier formation induced by Corsican HIEO.
In conclusion, our results demonstrate that NA, the major component of HIEO, reinforced the skin barrier function by increasing lipids and ceramide content in the SC by enhancing the expressions of ceramide synthesis-related enzymes required for the glucosylceramide pathway. Furthermore, both compounds increased epidermal differentiation by stimulating the expression of IVL (transcript and protein). In addition, we demonstrated for the first time that HIEO-regulated effects in this study are mediated by its principal component, neryl acetate. Therefore, we anticipate that Neryl acetate may be effective in improving skin barrier function and moisture retention in skin conditions with altered barrier such as aging.