A multi-functional and ecofriendly ingredient to fight against photo-aging
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Presented by: Emmanuel Coste
INTRODUCTION
Sunrays may cause photo-aging which consists in biological, and clinical skin alterations. Ultra-violet (UV) traditional filters and chemicals are widely used in cosmetic products as a preventive protection. However, they tend to have side effects on health and their impact on environment is now condemned.
In order to meet the demand for new, natural, ecofriendly photoprotecting ingredients, an original Entada phaseoloides seeds extract (EPSE) was designed. This tropical vine used in folk medicine is rich in bioactives constituents.
Here, we present a new, original, and patented extraction process for maximizing the content of active molecules of interest in EPSE. We then assessed the efficacy of EPSE to protect the skin from the noxious effects of sun rays and artificial irradiations. To that end, we evaluated the impact of UV and blue light exposure in the presence or in the absence of EPSE on several key features, namely genotoxicity, pro-inflammation, immunosuppression and melanogenesis.
METHODS
EPSE was obtained by a specific and patented maceration process including a selective endogenous enzymatic phase. Metabolites present in E. phaseoloides seeds were isolated and identified by High Performance Liquid Chromatography (HPLC). Their chemical characteristics such as UV absorption and anti-oxidant properties were determined by HPLC and usual biochemical assays respectively.
Under different UV radiations or blue light, the photoprotective functions of EPSE were evaluated on 2D and 3D models (human reconstructed epidermis, explants…) using various methods: DNA damages and apoptosis were monitored using specific cyclobutane pyrimidine dimers (CPD) immunodetection and H&E staining (sunburn cells counting) respectively. Anti-inflammatory and anti-immunosuppressive properties were evidenced by protein dosage (IL-6, IL-8, TNFa, MMP-1, galectin-7…) using ELISA assays. Melanin quantification was monitored by spectrophotometry.
RESULTS
Entada phaseoloides seeds contain two metabolites of interest: Entadamide A and phaseoloidin.
Entadamide A is a methylthiopropenoic acid conjugate that prevents the UV-induced photoisomerization of trans-urocanic acid (UCA, an endogenous compound present in the stratum corneum that has been described as the first protection against sun rays because of its capacity to absorb UV) into cis-UCA that has immunosuppressive activity. However, entadamide A is mainly present in an unstable glycosylated form in seeds.
Phaseoloidin is an antioxidant polyphenol found in high amounts in EPSE (>10% of dry weight). Its strong quenching properties contribute to the anti-oxidative properties of EPSE. But the seed also contains trace of its unstable aglycon form, homogentisic acid.
The patented selective hydrolysis process was achieved using endogenous enzymes of the seeds. It allowed for the selection and for the maximization of the stable aglycon form of entadamide A, and of phaseoloidin while preventing the formation of homogentisic acid.
By preventing trans-UCA isomerization by UV and by neutralizing the UV-generated free radicals, EPSE prevents UV-induced direct and indirect DNA alterations and cell death on 2D and 3D models.
Furthermore, the UVB-induced release of pro-inflammatory mediators was inhibited.
EPSE inhibits the UV-induced immunosuppression by preventing cis-UCA generation (because of the high concentration of entadamide A) and by normalizing the expression of Galectin-7, a lectin that represses immune cells activation, that was overexpressed after an exposure to UV.
Blue light has the most energetic waves of the visible spectrum, and it was described to cause collagen degradation and to lead to premature aging. The treatment with EPSE strongly inhibits the blue light-induced MMP-1 overexpression thus preserving collagen content within the skin.
Taken together, these results suggest that EPSE acts as an immunoprotector, and a broad spectrum photoprotector as it mitigates the impact of UV and blue light on the skin. Interestingly, EPSE was tested on irradiated melanocytes and underlines an inhibition of tyrosinase activity leading to a reduction in melanin production.
CONCLUSION
We have shown that EPSE is a cosmetic active ingredient with strong antioxidant and photoprotective abilities. This activity is due to a well-reasoned extraction process that specifically targeted bioactive metabolites such as entadamide A and phaseoloidin hence leading to a reliable and multifunctional extract.
Among the biological activities of EPSE, one of the most interesting could be its ability to modulate melanogenesis for preserving a bright and even skin tone while providing an efficient photoprotection. This may prove very interesting for some markets such as Asia.
Sunrays may cause photo-aging which consists in biological, and clinical skin alterations. Ultra-violet (UV) traditional filters and chemicals are widely used in cosmetic products as a preventive protection. However, they tend to have side effects on health and their impact on environment is now condemned.
In order to meet the demand for new, natural, ecofriendly photoprotecting ingredients, an original Entada phaseoloides seeds extract (EPSE) was designed. This tropical vine used in folk medicine is rich in bioactives constituents.
Here, we present a new, original, and patented extraction process for maximizing the content of active molecules of interest in EPSE. We then assessed the efficacy of EPSE to protect the skin from the noxious effects of sun rays and artificial irradiations. To that end, we evaluated the impact of UV and blue light exposure in the presence or in the absence of EPSE on several key features, namely genotoxicity, pro-inflammation, immunosuppression and melanogenesis.
METHODS
EPSE was obtained by a specific and patented maceration process including a selective endogenous enzymatic phase. Metabolites present in E. phaseoloides seeds were isolated and identified by High Performance Liquid Chromatography (HPLC). Their chemical characteristics such as UV absorption and anti-oxidant properties were determined by HPLC and usual biochemical assays respectively.
Under different UV radiations or blue light, the photoprotective functions of EPSE were evaluated on 2D and 3D models (human reconstructed epidermis, explants…) using various methods: DNA damages and apoptosis were monitored using specific cyclobutane pyrimidine dimers (CPD) immunodetection and H&E staining (sunburn cells counting) respectively. Anti-inflammatory and anti-immunosuppressive properties were evidenced by protein dosage (IL-6, IL-8, TNFa, MMP-1, galectin-7…) using ELISA assays. Melanin quantification was monitored by spectrophotometry.
RESULTS
Entada phaseoloides seeds contain two metabolites of interest: Entadamide A and phaseoloidin.
Entadamide A is a methylthiopropenoic acid conjugate that prevents the UV-induced photoisomerization of trans-urocanic acid (UCA, an endogenous compound present in the stratum corneum that has been described as the first protection against sun rays because of its capacity to absorb UV) into cis-UCA that has immunosuppressive activity. However, entadamide A is mainly present in an unstable glycosylated form in seeds.
Phaseoloidin is an antioxidant polyphenol found in high amounts in EPSE (>10% of dry weight). Its strong quenching properties contribute to the anti-oxidative properties of EPSE. But the seed also contains trace of its unstable aglycon form, homogentisic acid.
The patented selective hydrolysis process was achieved using endogenous enzymes of the seeds. It allowed for the selection and for the maximization of the stable aglycon form of entadamide A, and of phaseoloidin while preventing the formation of homogentisic acid.
By preventing trans-UCA isomerization by UV and by neutralizing the UV-generated free radicals, EPSE prevents UV-induced direct and indirect DNA alterations and cell death on 2D and 3D models.
Furthermore, the UVB-induced release of pro-inflammatory mediators was inhibited.
EPSE inhibits the UV-induced immunosuppression by preventing cis-UCA generation (because of the high concentration of entadamide A) and by normalizing the expression of Galectin-7, a lectin that represses immune cells activation, that was overexpressed after an exposure to UV.
Blue light has the most energetic waves of the visible spectrum, and it was described to cause collagen degradation and to lead to premature aging. The treatment with EPSE strongly inhibits the blue light-induced MMP-1 overexpression thus preserving collagen content within the skin.
Taken together, these results suggest that EPSE acts as an immunoprotector, and a broad spectrum photoprotector as it mitigates the impact of UV and blue light on the skin. Interestingly, EPSE was tested on irradiated melanocytes and underlines an inhibition of tyrosinase activity leading to a reduction in melanin production.
CONCLUSION
We have shown that EPSE is a cosmetic active ingredient with strong antioxidant and photoprotective abilities. This activity is due to a well-reasoned extraction process that specifically targeted bioactive metabolites such as entadamide A and phaseoloidin hence leading to a reliable and multifunctional extract.
Among the biological activities of EPSE, one of the most interesting could be its ability to modulate melanogenesis for preserving a bright and even skin tone while providing an efficient photoprotection. This may prove very interesting for some markets such as Asia.