(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.

(1) Background: Ultraviolet radiation takes part in photoaging and pigmentation disorders on skin. Epigallocatechin gallate (EGCG) is a well-known brightening and photoprotective compound but it faces limitations in terms of stability and solubility. (2) Methods: A more stable and water-soluble glucoside called EGCG-G1 was obtained by enzymatic glucosylation of EGCG. In vitro and ex vivo experiments evaluated EGCG-G1 skin penetration, antioxidant activity, and antimelanogenic properties compared to EGCG. This gene expression study characterized the pathways impacted by EGCG-G1. Four clinical studies covering phototypes I to V, at various ages, and different skin areas, using several tools, were conducted to assess the effect of EGCG-G1 on skin hyperpigmentation and tone. The impact of glucoside on skin microbiota, especially Lactobacillus sp., was assessed through in vitro and in vivo investigations. (3) Results: EGCG-G1 better penetrated the epidermis than EGCG due to a possible interaction with GLUT1. EGCG-G1 presented similar antioxidant activity to that of EGCG and decreased melanogenesis through the inhibition of 13 genes, including MITF. The skin Lactobacillus population increased with EGCG-G1, which promoted bacterial growth in vitro as prebiotic, and induced the release of a microbial brightening metabolite. Clinical trials demonstrated EGCG-G1 to decrease hyperpigmented spots and increase skin brightness and homogeneity in a large panel of phototypes, outperforming EGCG and vitamin C. (4) Conclusions: Glucosylation of EGCG maintained its photoprotective antioxidant properties and enhanced penetration across the epidermis. EGCG-G1 demonstrated brightening properties on all skin types by down-regulation of melanogenesis pathways and indirectly by skin microbiota stimulation.

Microbiome supplementation initially targeted the gut microbiota but has since been extended to the skin. A new category, psychobiotics, defined beneficial compounds with a positive action on microbiota, providing benefits to the host’s mental health. Pogostemon cablin leaf extract, proven to alleviate scalp dryness, was clinically evaluated on volunteers presenting dry scalp with flakes. A metagenomics study and sebum production analysis were performed, coupled to flakes scoring. The benefits of Pogostemon cablin leaf extract on emotions were assessed through three neuroscientific methods. Through this study, we proved that the skin microbiota of dry scalp was imbalanced, with increased alpha diversity and decreased Cutibacterium relative abundance compared to oilier skin. After applying our ingredient for one month, microbiota was rebalanced with a decrease in alpha diversity and increase in Cutibacterium relative abundance compared to the initial profile. Microbiota rebalancing led to an increase in scalp sebum and decrease in dry flakes compared to the start of the study. This global rebalancing improved the emotional state of people with scalp dryness who expressed more positive emotions after treatment.

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.

Recent evidence suggests that microbiota-derived porphyrins contribute to skin aging, a phenomenon termed porphyr’aging. These pro-inflammatory molecules alter the expression of genes involved in senescence, trigger melanogenesis, and decrease collagen I synthesis in skin. The aim of this study was to evaluate the anti-aging properties of an upcycled Laminaria hyperborea extract (LHE) targeting bacterial porphyrins discovered after screening. The impact of LHE on porphyrin biosynthesis and on melanogenesis and wrinkles was evaluated using in vitro and ex vivo tests and by conducting a double-blinded vs. placebo clinical trial. LHE significantly reduced coproporphyrin III production in Gram-positive skin bacteria and significantly decreased porphyrin levels in vivo at the skin surface. This activity was supported by a specific composition of LHE, comprising laminaran and mannitol. It also significantly decreased melanin content in skin explants and pigmentation in the clinical study (−5.9%). This effect was particularly pronounced in dark spots (ITA +39.9%), and the number of precursor spots also decreased (−6.9%). In addition, LHE significantly stimulated type I α-1 pro-collagen production in fibroblasts and increased collagen I and elastin expression in skin explants. These results were consistent with the clinical study, showing significant reductions in wrinkle number (−9.8%) and area (−5.8%). These findings suggest that targeting microbiota-derived porphyrins and their consequences may represent a promising approach to reduce the visible signs of aging.

Sebum is a well-recognised protection of the skin and minor changes on its composition and quantity impact skin homeostasis. Over production indu | POSTER