Prebiotic effect of galacto-oligosaccharides on the skin microbiota and determination of their diffusion properties.

OBJECTIVE: Recently, prebiotics are attracting plenty of attention in the field of skin care, since it is found that they are able to support the balance of beneficial and harmful microorganisms on the skin, and accordingly prevent several skin conditions associated with microbial imbalance. Topical application of prebiotics, although insufficiently investigated, holds great promise in improving skin health. The purpose of this research was to determine the prebiotic potential of galacto-oligosaccharides (GOS) for skin microbiota and suitability for incorporation in different topical formulations, and finally, provide insights into their diffusion properties. METHODS: The prebiotic effect of GOS was evaluated through the influence on the growth of Staphylococcus epidermidis and Staphylococcus aureus, the most common resident and pathogenic bacterium of the skin microbiota, respectively. Also, with the future use of GOS in cosmetic products in mind, the diffusion of GOS molecules from two different topical formulations, hydrogel and oil-in-water (O/W) gel emulsion, was monitored employing Franz diffusion cell and two systems-with cellulose acetate membrane and transdermal diffusion test model, Strat-M® membrane. Course of fermentation and the amount of diffused GOS molecules were monitored using high-performance liquid chromatography (HPLC). RESULTS: The in vitro results revealed that GOS at a concentration of 5% (w/v) has a pronounced stimulatory effect on S. epidermidis, while simultaneously showing an inhibitory effect on S. aureus, both in nutrient broth and cosmetic formulations. GOS trisaccharide and tetrasaccharide diffusion coefficients from O/W gel emulsion were calculated to be 5.61·10-6  cm2  s-1 and 1.41·10-8  cm2  s-1 , respectively. The diffusion coefficient of GOS trisaccharides from hydrogel was 3.22·10-6  cm2  s-1 , while it was not determined for tetrasaccharides due to low diffused concentration. Transdermal diffusion tests revealed that GOS incorporated in two formulations stays at the surface of the skin even after 24 h. CONCLUSION: When applied in adequate concentration, GOS has the potential to be used as a skin prebiotic. Novel GOS enriched formulations, Aristoflex® AVC-based hydrogel and Heliogel™-based O/W gel emulsion, provided efficient diffusion and delivery of prebiotic GOS molecules to the skin surface.

OBJECTIF: Récemment, les prébiotiques attirent beaucoup d'attention dans le domaine des soins de la peau, car il a été constaté qu'ils sont capables de soutenir l'équilibre des micro-organismes bénéfiques et nocifs sur la peau et, par conséquent, de prévenir plusieurs affections cutanées associées à un déséquilibre microbien. L'application topique de prébiotiques, bien qu'insuffisamment étudiée, est très prometteuse pour améliorer la santé de la peau. Le but de cette recherche était de déterminer le potentiel prébiotique des galacto-oligosaccharides (GOS) pour le microbiote cutané et leur aptitude à être incorporés dans différentes formulations topiques, et enfin, de fournir des informations sur leurs propriétés de diffusion. MÉTHODES: L'effet prébiotique du GOS a été évalué à travers l'influence sur la croissance de Staphylococcus epidermidis et de Staphylococcus aureus, les bactéries résidentes et pathogènes les plus courantes du microbiote cutané, respectivement. De plus, en gardant à l'esprit l'utilisation future du GOS dans les produits cosmétiques, la diffusion des molécules de GOS à partir de deux formulations topiques différentes, l'hydrogel et l'émulsion de gel huile-dans-eau (H/E), a été surveillée à l'aide d'une cellule de diffusion de Franz et de deux systèmes - avec de la cellulose membrane en acétate et modèle de test de diffusion transdermique, membrane Strat-M®. Le cours de la fermentation et la quantité de molécules de GOS diffusées ont été surveillés en utilisant la chromatographie liquide à haute performance (HPLC). RESULTATS: Les résultats in vitro ont révélé que le GOS à une concentration de 5% (p/v) a un effet stimulant prononcé sur S. epidermidis, tout en montrant simultanément un effet inhibiteur sur S. aureus, à la fois dans les bouillons nutritifs et les formulations cosmétiques. Les coefficients de diffusion GOS trisaccharide et tétrasaccharide de l'émulsion de gel H/E ont été calculés comme étant de 5,61·10−6 cm2 s−1 et 1,41·10-8 cm2 s−1 , respectivement. Le coefficient de diffusion des trisaccharides GOS à partir de l'hydrogel était de 3,22·10−6 cm2 s−1 , alors qu'il n'a pas été déterminé pour les tétrasaccharides en raison de la faible concentration diffusée. Des tests de diffusion transdermique ont révélé que le GOS incorporé dans deux formulations reste à la surface de la peau même après 24 h. CONCLUSION: Lorsqu'il est appliqué à une concentration adéquate, le GOS a le potentiel d'être utilisé comme prébiotique cutané. De nouvelles formulations enrichies en GOS, l'hydrogel à base d'Aristoflex® AVC et l'émulsion de gel H/E à base d'Heliogel™, ont permis une diffusion et une délivrance efficaces des molécules GOS prébiotiques à la surface de la peau.

Freeze vs. Spray Drying for Dry Wild Thyme (Thymus serpyllum L.) Extract Formulations: The Impact of Gelatin as a Coating Material.

Freeze drying was compared with spray drying regarding feasibility to process wild thyme drugs in order to obtain dry formulations at laboratory scale starting from liquid extracts produced by different extraction methods: maceration and heat-, ultrasound-, and microwave-assisted extractions. Higher total powder yield (based on the dry weight prior to extraction) was achieved by freeze than spray drying and lower loss of total polyphenol content (TPC) and total flavonoid content (TFC) due to the drying process. Gelatin as a coating agent (5% w/w) provided better TPC recovery by 70% in case of lyophilization and higher total powder yield in case of spray drying by diminishing material deposition on the wall of the drying chamber. The resulting gelatin-free and gelatin-containing powders carried polyphenols in amount ~190 and 53-75 mg gallic acid equivalents GAE/g of powder, respectively. Microwave-assisted extract formulation was distinguished from the others by a higher content of polyphenols, proteins and sugars, higher bulk density and lower solubility. The type of the drying process mainly affected the position of the gelatin-derived -OH and amide bands in FTIR spectra. Spray-dried formulations compared to freeze-dried expressed higher thermal stability as confirmed by differential scanning calorimetry analysis and a higher diffusion coefficient; the last feature can be associated with the lower specific surface area of irregularly shaped freeze-dried particles (151-223 µm) compared to small microspheres (~8 µm) in spray-dried powder.

Formulation and characterization of liposomal encapsulated systems of bioactive ingredients from traditional plant mountain germander (Teucrium montanum L.) for the incorporation into coffee drinks.

Conventional and innovative (microwave-assisted and subcritical water extraction) techniques were applied to investigate the bioactive content of traditional plant - Teucrium montanum. Verbascoside and echinacoside, identified and quantified using LC-MS/MS and HPLC-PAD, were found to be the predominant phenolics in all extracts. Infusion (30 °C, 30 min) was characterized with the highest total phenolic content and antioxidant capacity and was further used for encapsulation into liposomes. Formulation of liposomes with a high encapsulation efficiency of echinacoside (68.27%) and verbascoside (80.60%), satisfactory physical properties, including size (326.2 nm) and polydispersity index (0.34), was achieved, although determined zeta potential (-23.03 mV) indicated their instability. Formulated liposomes were successfully coated with pectin and alginate that was also proved by FTIR analysis. Liposomes coated with pectin showed the most desirable in vitro digestion release of verbascoside and echinacoside, while alginate as liposome surface layer proved to be more appropriate for their retention during storage time.

Development, Characterization and Incorporation of Alginate-Plant Protein Covered Liposomes Containing Ground Ivy (Glechoma hederacea L.) Extract into Candies.

Ground ivy (Glechoma hederacea L.) has been known as a medicinal plant in folk medicine for generations and, as a member of the Lamiaceae family, is characterized with a high content of rosmarinic acid. The aim of the present study was to formulate delivery systems containing bioactive compounds from ground ivy in encapsulated form and incorporated into candies. Liposomes were examined as the encapsulation systems that were additionally coated with an alginate-plant protein gel to reduce leakage of the incorporated material. Bioactive characterization of the ground ivy extract showed a high content of total phenolics (1186.20 mg GAE/L) and rosmarinic acid (46.04 mg/L). The formulation of liposomes with the high encapsulation efficiency of rosmarinic acid (97.64%), with at least a double bilayer and with polydisperse particle size distribution was achieved. Alginate microparticles reinforced with rice proteins provided the highest encapsulation efficiency for rosmarinic acid (78.16%) and were therefore used for the successful coating of liposomes, as confirmed by FT-IR analysis. Coating liposomes with alginate-rice protein gel provided prolonged controlled release of rosmarinic acid during simulated gastro-intestinal digestion, and the same was noted when they were incorporated into candies.