Our understanding of the interplay between skin microbiota and the skin's health status is growin... more Our understanding of the interplay between skin microbiota and the skin's health status is growing. Consequently, the cosmetics industry is increasingly concerned with ensuring that beauty products do not adversely affect this microbiota and skin health. Prior to implementing demanding sequencing-based analyses of skin microbiota, an agile approach is needed to provide a first estimate of the short-term impact of cosmetic ingredients on the viability of skin microbiota. A standardized methodology, including topical applications, swabbing, and bacterial colony-counting, was set up and evaluated. The skin's bacterial density was longitudinally monitored after repeated applications of two reference compounds: physiological saline, assumed to be neutral, and chlorhexidine, expected to have a perturbing effect. Healthy volunteers were enrolled in six clinical studies, involving application of physiological saline and chlorhexidine to both sides of the neck. Over 7 days, skin swabs were collected at defined time points, and bacterial density was assessed based on a classical colony-counting approach. The longitudinal assessment of skin bacterial density proved highly robust, with a very steady inter-seasonal impact of chlorhexidine on skin bacterial density. This consolidated methodology supported the development of an easy-to-understand viability score that quantifies the intrinsic short-term impact of an ingredient on skin bacterial populations.
Background and AimsDark spots, brown spots, or hyperpigmented spots (HPS) are oval or irregular b... more Background and AimsDark spots, brown spots, or hyperpigmented spots (HPS) are oval or irregular brown areas of skin. Their emergence is associated with dysregulation of the immune system, and may also be caused by a deficiency in stromal cell‐derived factor‐1, leading to perturbed melanogenesis and accumulation of melanosomes within neighboring keratinocytes. The skin microbiota (living microorganisms present on the surface of the skin) is known to play essential roles in maintaining skin homeostasis and in regulating the immune system. Here, we investigated whether the microbiota could play a role in the emergence of HPS.MethodsThe clinical study involved 38 European women, selected from among 74 volunteers. Participants were divided into two groups depending on the spot areas measured on their faces. The study was designed to avoid conflicting factors: both groups presented similar skin pH, hydration, transepidermal water loss, and sebum levels. The two cohorts were also age‐matched, with a mean of 29‐years‐old for both.ResultsAlpha‐diversity of the microbiota was similar for the two groups. On skins with more HPS, seven bacterial genera were identified in significantly higher proportions and included opportunistic pathogens and inflammatory bacteria. Six bacterial genera, including bacteria showing antioxidant and anti‐UV properties, were identified in significantly higher proportions on less spotted skins. Cross‐domain association networks revealed distinct co‐occurrences of genera between the two groups, suggesting nonidentical community structures and exchanges, depending on the HPS status.ConclusionOur results reveal specific microbiota composition and networks on skins based on HPS status. Changes could alter communication with the immune system, leading to the emergence of dark spots. As an essential part of the overall skin ecosystem, and through its interaction with the skin matrix, the skin microbiota and its maintenance could be considered a new target for skincare applications.
Purification and characterization of an aminopeptidase A from Staphylococcus chromogenes and its use for the synthesis of amino-acid derivatives and dipeptides
European journal of biochemistry, 1993
An aminopeptidase with original specificity was purified 3800-fold to homogeneity from a cellular... more An aminopeptidase with original specificity was purified 3800-fold to homogeneity from a cellular extract of Staphylococcus chromogenes. The enzyme was specific for acidic amino acids (Asp and Glu) at the N-terminus of peptides and thus can be classified as an aminopeptidase A. However, its specificity was not restricted to acidic amino acids: alpha-hydroxy acids such as L-malic and L-lactic acids were also accepted in position P1. The enzyme had a broad specificity for the residue at position P' 1, accepting all types of amino acids, including Pro, in this position. The optimal conditions for the hydrolysis of Asp-Phe-NH2 were pH 9.5 and 60 degrees C. The enzyme was inhibited by chelating agents and serine-protease inhibitors. The activity lost by treatment with chelating agents could be restored by Mn2+ or Zn2+ which also stimulated the native enzyme. This suggests that it is a metalloprotease with a serine residue essential for the activity. The native enzyme had an apparent molecular mass of 430 kDa on gradient-gel electrophoresis and subunits of 43 kDa as determined by SDS/PAGE. The enzyme catalyzed the synthesis of peptide and amino acid derivatives such as Asp-Phe-OMe (Aspartame) and malyl-Tyr-OEt from L-Asp and L-malic acid as acyl donors and L-Phe-OMe and L-Tyr-OEt as nucleophiles, respectively. The use of the enzyme as a reagent in protease-catalyzed peptide synthesis, N-terminal protection and subsequent deprotection, is described.
Baicalin is a biologically active flavone glucuronide with poor water solubility that can be enha... more Baicalin is a biologically active flavone glucuronide with poor water solubility that can be enhanced via glucosylation. In this study, the transglucosylation of baicalin was successfully achieved with CGTases from Thermoanaerobacter sp. and Bacillus macerans using α-cyclodextrin as a glucosyl donor. The synthesis of baicalin glucosides was optimized with CGTase from Thermoanaerobacter sp. Enzymatically modified baicalin derivatives were α-glucosylated with 1 to 17 glucose moieties. The two main glucosides were identified as Baicalein-7-O-α-D-Glucuronidyl-(1→4′)-O-α-D-Glucopyranoside (BG1) and Baicalein-7-O-α-D-Glucuronidyl-(1→4′)-O-α-D-Maltoside (BG2), thereby confirming recent findings reporting that glucuronyl groups are acceptors of this CGTase. Optimized conditions allowed for the attainment of yields above 85% (with a total glucoside content higher than 30 mM). BG1 and BG2 were purified via centrifugal partition chromatography after an enrichment through deglucosylation with a...
Targeting SDF‐1 as an efficient strategy to resolve skin hyperpigmentation issues with Himanthalia elongata extract
Journal of Cosmetic Dermatology
BackgroundDuring aging, human skin is facing hyperpigmentation disorders: senile lentigo (chronob... more BackgroundDuring aging, human skin is facing hyperpigmentation disorders: senile lentigo (chronobiologic aging) leads to loss of melanogenesis' control while solar lentigo (UV exposure) promotes an increase of oxidized proteins, melanogenesis, and lipofuscin.AimsStromal‐cell‐derived‐factor‐1 (SDF‐1) was identified as key regulator of hyperpigmentation and its expression is reduced in senescent fibroblasts, highlighting this protein as new target for skin hyperpigmentation.MaterialsWe developed two skin explant models mimicking of senile and solar lentigo, based on H2O2 systemic treatment and UV irradiation, respectively. We evaluated Himanthalia elongata extract (HEX) on these models after 5 days of treatment and analyzed SDF‐1 expression and skin pigmentation. For solar lentigo, we also analyzed oxidized proteins and lipofuscin accumulation. Finally, we evaluated HEX in vivo on nearly 100 multi ethnicities' volunteers.ResultsSDF‐1 expression decreased in senile lentigo mode...
1) Background: Preclinical studies report that the ethanolic fraction from Mangifera indica leave... more 1) Background: Preclinical studies report that the ethanolic fraction from Mangifera indica leaves is a potential anti-acne agent. Nevertheless, the biological activity of Mangifera indica leaves has scarcely been investigated, and additional data are needed, especially in a clinical setting, for establishing the actual effectiveness of Mangifera indica extract as an active component of anti-acne therapy. (2) Methods: The evaluation of the biological activity of Mangifera indica extract was carried out through different experimental phases, which comprised in silico, in vitro, ex vivo and clinical evaluations. (3) Results: In silico and in vitro studies allowed us to identify the phytomarkers carrying the activity of seboregulation and acne management. Results showed that Mangifera indica extract reduced lipid production by 40% in sebocytes, and an improvement of the sebum quality was reported after the treatment in analyses performed on sebaceous glands from skin explants. The evaluation of the sebum quantity and quality using triglyceride/free fatty acid analysis conducted on Caucasian volunteers evidenced a strong improvement and a reduction of porphyrins expression. The C. acnes lipase activity from a severe acne phylotype was evaluated in the presence of Mangifera indica, and a reduction by 29% was reported. In addition, the analysis of the skin microbiota documented that Mangifera indica protected the microbiota equilibrium while the placebo induced dysbiosis. (4) Conclusions: Our results showed that Mangifera indica is microbiota friendly and efficient against lipase activity of C. acnes and supports a role for Mangifera indica in the therapeutic strategy for prevention and treatment of acne.
ObjectiveSkin lipids are essential in every compartment of the skin where they play a key role in... more ObjectiveSkin lipids are essential in every compartment of the skin where they play a key role in various biological functions. Interestingly, their role is central in the maintenance of hydration which is related to skin barrier function and in the skin structure through adipose tissue. It is well described today that skin lipids are affected by ageing giving skin sagging, wrinkles and dryness. Thereby, developing cosmetic actives able to reactivate skin lipids would be an efficient ant‐ageing strategy. Due to the strong commitment of our scientists to innovate responsibly and create value, they designed a high value active ingredient named here as Vetiver extract, using a ground‐breaking upcycling approach. We evidenced that this unique extract was able to reactivate globally the skin lipids production, bringing skin hydration and plumping effect for mature skin.MethodIn order to demonstrate the global renewal of lipids, we evaluated the lipids synthesis on cutaneous cells that pr...
Targeting Inflammatory Pathways to Reduce Dark Circles and Puffiness
D ark circles are a common cosmetic problem for a large number of peo- ple. Because, most of the ... more D ark circles are a common cosmetic problem for a large number of peo- ple. Because, most of the cosmetic products available on the market targeted either blood micro-circulation or covered the skin hyperpig- mentation, we decided to develop a cosmetic ingredient, which targets the inflammatory, lymphatic and vascular origin of dark circles. In this study the efficacy of the active ingredient was assessed in vitro and on human volun- teers. Our studies have shown the effectiveness of this ingredient to reduce the dark circles after 15 and 30 days of treatments. The mechanism of action demonstrated is based on both anti-inflammatory and draining properties. The active ingredient showed anti-inflammatory effects on keratinocytes by strongly inhibiting NF-KB pathway-driven IL-8 and CXCL1 releases. The inhibi- tory effect of the active ingredient was not mediated by a direct inhibition of NF-KB translocation but by inhibition of the NF-KB activity. This active in- gredient improves the ...
How the skin microbiome influences ingredient action of cosmetics. Through their effects on metabolism, bacteria in the skin affect whether active ingredients will be safe and effective for human health
ObjectiveIn hair care cosmetic products’ evaluation, one commonly used method is to evaluate the ... more ObjectiveIn hair care cosmetic products’ evaluation, one commonly used method is to evaluate the hair appearance as a gold standard in order to determine the effect of an active ingredient on the final state of the hair via visual appreciation. Although other techniques have been proposed for a direct analysis of the hair fibres, they give only surface or structural information, without any accurate molecular information. A different approach based on confocal Raman spectroscopy has been proposed for tracking in situ the molecular change in the keratin directly in the human hair fibres. It presents a high molecular specificity to detect chemical interactions between molecules and can provide molecular information at various depths at the cortex and cuticle levels.MethodsTo evaluate the potential of confocal Raman spectroscopy in testing the efficiency of cosmetic ingredients on keratin structure, we undertook a pilot study on the effectiveness of a smoothing shampoo on natural human...
Enzymatic Peptide Synthesis Using New Water-Soluble Amino Acid Derivatives
Progress in Biotechnology, 1992
Abstract N-L-malyl-L-tyrosine ethyl ester (MTEE), produced at a large scale by a Staphylococcus c... more Abstract N-L-malyl-L-tyrosine ethyl ester (MTEE), produced at a large scale by a Staphylococcus chromogenes aminopeptidase, was used as a highly water-soluble N-protected form of L-tyrosine in the kinetically controlled synthesis of N-L-malyl-L-tyrosylglycylglycine ethyl ester (MTGGEE) and N-L-malyl-L-tyrosylarginine ethyl ester (MTAEE) by α-chymotrypsin. The S. chromogenes aminopeptidase was used for product deprotection, allowing the proposal of a selective and mild complete enzymatic peptide synthesis process.
Digital stress is a newly identified cosmetic stress that is mainly characterized by blue light e... more Digital stress is a newly identified cosmetic stress that is mainly characterized by blue light exposure. The effects of this stress have become increasingly important with the emergence of personal digital devices, and its deleterious effects on the body are now well-known. Blue light has been observed to cause perturbation of the natural melatonin cycle and skin damage similar to that from UVA exposure, thus leading to premature aging. “A melatonin-like ingredient” was discovered in the extract of Gardenia jasminoides, which acts as a filter against blue light and as a melatonin-like ingredient to prevent and stop premature aging. The extract showed significant protective effects on the mitochondrial network of primary fibroblasts, a significant decrease of −86% in oxidized proteins on skin explants, and preservation of the natural melatonin cycle in the co-cultures of sensory neurons and keratinocytes. Upon analysis using in silico methods, only the crocetin form, released throug...
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