Article

Alpha-hydroxyacids and carboxylic acids

Wiley
Journal of Cosmetic Dermatology
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Abstract

The carboxylic acids include alpha-hydroxyacids (AHAs), polyhydroxy acids (PHAs), aldobionic acids (ABAs), retinoic acid, vitamin C and azelaic acid. They all have therapeutic actions. AHAs, PHAs and ABAs are organic hydroxyacids, a group of natural and physiological substances which can modulate skin keratinization and increase biosynthesis of dermal components. Because of these effects, AHAs, PHAs and ABAs are therapeutically effective or beneficial for topical treatment of dry skin, rough skin, acne, rosacea, warts, eczema, psoriasis and skin changes associated with ageing, including wrinkles and photoageing. In addition, PHAs and ABAs, which are antioxidants, are topically beneficial for sensitive or diseased skin and for the prevention of oxidative damage caused by UV radiation. The vitamin A derivatives, known as retinoids, include three that are found physiologically. Retinoic acid is the most potent of these in promoting proliferation and differentiation of epithelial cells, and in stimulating biosynthesis of collagen I and III. Because of these actions, retinoic acid is therapeutically effective for topical treatment of acne, actinic keratoses and photoaged skin. Vitamin C, which is l-ascorbic acid and a lactone form of 3-keto-polyhydroxy acid, is a water-soluble antioxidant. Because of this property vitamin C has been promoted for topical prevention of skin damage caused by UV radiation. Azelaic acid has been shown to normalize keratinization in the follicular infundibulum, exert an antibacterial effect against Propionibacterium acnes and inhibit melanogenesis and so has been used for topical treatment of acne and melasma. The carboxylic acids display similarities and differences in their topical actions and therapeutic applications.

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... Hydroxy acids are a group of organic chemicals consisting of a carboxylic acid group with one or more hydroxyl groups. This acid is naturally present in cane sugar, curds, honey, cucumbers, lemons, grapes, apples, etc. (Yu &;Van Scott, 2004). Hidroxy acid is also known as fruit acid because it is mostly found in fruit. ...
... Hydroxy acids are a group of organic chemicals consisting of a carboxylic acid group with one or more hydroxyl groups. This acid is naturally present in cane sugar, curds, honey, cucumbers, lemons, grapes, apples, etc. (Yu &;Van Scott, 2004). Hidroxy acid is also known as fruit acid because it is mostly found in fruit. ...
... The first generation of HA was α-hydroxy acids (AHAs), which are carboxylic acids with hydroxy groups attached to alpha carbons (e.g. glycolic acid and lactic acid) (Yu & Van Scott, 2004). Glycolic acid with its chemical name is hydroxy acetic acid, which was the first compound of this HA to be introduced into skin care products. ...
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Introduction: Hidroxy acid is one of the active substances that is widely used in the cosmetic field. Its use is very wide, but there are several classes of hydroxy acid that are irritative. The use of hydroxy acids can cause skin redness, itching, and tension in the skin. Other hydroxy acids are needed that can meet consumer needs without unwanted side effects. Method: This article uses research methods through literature search methods by collecting journals related to research objectives. Articles were found on Google Scholar's seaching engine as many as 27 articles. Objective: To determine the effectiveness of gluconolactone as a skin barrier, antiaging, and as an antiacne. Result and Discussion: The antioxidant effect of gluconolactone can also be used as a sunscreen by capturing free radicals formed when the skin is exposed to the sun. Conclusion: From the search it was found that gluconolacntone can act as a skin barrier protector, anti-acne as well as antianging
... It has been shown that alpha-hydroxy acids, such as citric acid and malic acid, can modulate skin keratinization and positively influence the content of elastin, collagen, and glycosaminoglycans. These properties allow these simple plant metabolites to be used as photoprotective substances, positively influencing skin hydration and reducing acne lesions and wrinkles [14,15]. ...
... The positive relationship between the antioxidant scavenging ability of the extracts and the amount of extracted isoflavones was proven by the calculated correlation coefficients (Table 3). This phenomenon was expected since isoflavones display free-radical scavenging potential [14]. At the same time, both the allantoin and alpha-hydroxy acids did not exhibit a positive correlation with the scavenging of ABTS (Table 3), which is in accordance with previous reports [18,50]. ...
... At the same time, both the allantoin and alpha-hydroxy acids did not exhibit a positive correlation with the scavenging of ABTS (Table 3), which is in accordance with previous reports [18,50]. However, alpha-hydroxy acids are considered antioxidant molecules since they are capable of oxidation inhibition and the suppression of free-radical formation [14], while allantoin exhibits the induction of antioxidant enzyme activity [51]. Interestingly, pure H 2 O turned out to be the most suitable solvent for soluble phenol extraction (Figure 5b). ...
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Soybeans are commonly known as a valuable source of biologically active compounds including isoflavones as well as allantoin and alpha-hydroxy acids. Since these compounds exhibit skin therapeutic effects, they are widely used in the cosmetic and pharmaceutical industries. The presented paper shows the optimization of three solvent systems (ethanol, water, and 1,3-propanediol) to increase the extraction efficiency of isoflavones (daidzin, genistin, 6″-O-malonyldaidzin, 6″-O-malonylglycitin, 6″-O-malonylgenistin), allantoin, and alpha-hydroxy acids (citric acid, malic acid) from soybean leaves. A simplex centroid mixture design for three solvents with interior points was applied for the experimental plan creation. Based on the obtained results of metabolite extraction yield in relation to solvent composition, polynomial regression models were developed. All models were significant, with predicted R-squared values between 0.77 and 0.99, while in all cases the model's lack of fit was not significant. The optimal mixture composition enabling the maximization of extraction efficiency was as follows: 32.9% ethanol, 53.9% water, and 13.3% propanediol (v/v/v). Such a mixture composition provided the extraction of 99%, 91%, 100%, 92%, 99%, 70%, 92%, and 69% of daidzin, genistin, 6″-O-malonyldaidzin, 6″-O-malonylglycitin, 6″-O-malonylgenistin, allantoin, citric acid, and malic acid, respectively. The solvent mixture composition developed provides a good extraction efficiency of the metabolites from soybean leaves and high antioxidant properties.
... PHAs are a group of chemical compounds used in skincare peels. PHA peels offer a milder alternative to traditional chemical peels, providing exfoliation and various skin benefits [57]. ...
... As a result, PHA peels are generally considered gentler and more suitable for sensitive skin types [58]. PHAs are frequently combined with additional compounds, including antioxidants, soothing agents, or hydrating components, to maximize the overall effects of the peel and reduce any potential irritation or dryness [57]. ...
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Acne vulgaris stands out as the most prevalent skin disorder among teenagers and young adults, causing physical discomfort and considerable economic and psychological burdens on individuals and society. A wide range of topical and systemic therapies are available in acne treatment. Chemical peeling is a skin resurfacing technique designed to rebuild healthy skin using exfoliating substances, a simple and affordable process with various dermatological uses. Chemical peels, classified as superficial, medium, and deep, have been utilized for acne vulgaris and multiple other skin issues. In these chemical peels, a diverse range of chemical substances is employed, each with its unique mode of action. Among these, α-hydroxy and β-hydroxy acids have gathered attention for their efficacy in reducing acne lesions and enhancing overall skin appearance. Acids, such as salicylic acid, glycolic acid, or lactic acid, are commonly used in chemical peels due to their exfoliating and sebum-regulating properties. Despite the widespread use of these acids, there exists a lack of consensus regarding the most effective acid type and concentration for treating acne-prone skin. This review aims to bridge this knowledge gap by evaluating the effectiveness and safety of various organic acids used in chemical peels specifically for acne-prone skin. The findings of this comprehensive bibliographic review indicate that organic acid-based chemical peels represent effective and safe treatment options for individuals with acne-prone skin. Their adaptability sets these treatments apart; the choice of organic acid can be tailored to meet individual patient needs and tolerability levels. This personalized approach ensures that patients receive optimal care while minimizing the risks associated with the treatment. As research in this field progresses, it is anticipated that a more nuanced understanding of the ideal acid type and concentration will emerge, further enhancing the efficacy and safety of chemical peels for acne-prone skin.
... These compounds may contribute to the overall sensory experience and moisturizing effects of skincare formulations. Phthalic acid, 6-ethyl-3-octyl butyl ester-a carboxylic acid derivative-may offer benefits such as improved skin penetration and moisturization [41,42]. Furthermore, the diterpene compound 3,7,11,15-tetramethylhexadec-2-en-1-ol, in addition to its antioxidant potential, may exhibit unique characteristics that contribute to skin health and anti-aging effects [43,44]. ...
... improved skin penetration and moisturization [41,42]. Furthermore, the diterpene compound 3,7,11,15-tetramethylhexadec-2-en-1-ol, in addition to its antioxidant potential, may exhibit unique characteristics that contribute to skin health and anti-aging effects [43,44]. ...
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Marine macroalgae, such as Padina boergesenii, are gaining recognition in the cosmetics industry as valuable sources of natural bioactive compounds. This study aimed to investigate the biochemical profile of P. boergesenii and evaluate its potential as a cosmetic ingredient. Fourier-transform infrared (FTIR), gas chromatography-mass spectrometry (GCMS), and high-resolution liquid chromatography-mass spectrometry quadrupole time-of-flight (HRLCMS QTOF) analyses were employed to assess the functional groups, phycocompounds, and beneficial compounds present in P. boergesenii. Pigment estimation, total phenol and protein content determination, DPPH an-tioxidant analysis, and tyrosinase inhibition assay were conducted to evaluate the extracts' ability to counteract oxidative stress and address hyperpigmentation concerns. Elemental composition and amino acid quantification were determined using inductively coupled plasma atomic emission spectrometry (ICP-AES) and HRLCMS, respectively. FTIR spectroscopy confirmed diverse functional groups, including halo compounds, alcohols, esters, amines, and acids. GCMS analysis identified moisturizing, conditioning, and anti-aging compounds such as long-chain fatty alcohols, fatty esters, fatty acids, and hydrocarbon derivatives. HRLCMS QTOF analysis revealed phenolic compounds, fatty acid derivatives, peptides, terpenoids, and amino acids with antioxidant, anti-inflammatory, and skin-nourishing properties. Elemental analysis indicated varying concentrations of elements, with silicon (Si) being the most abundant and copper (Cu) being the least abundant. The total phenol content was 86.50 µg/mL, suggesting the presence of antioxidants. The total protein content was 113.72 µg/mL, indicating nourishing and rejuvenating effects. The ethanolic extract exhibited an IC 50 value of 36.75 µg/mL in the DPPH assay, indicating significant antioxidant activity. The methanolic extract showed an IC 50 value of 42.784 µg/mL. Furthermore, P. boergesenii extracts demonstrated 62.14% inhibition of tyrosinase activity. This comprehensive analysis underscores the potential of P. boergesenii as an effective cosmetic ingredient for enhancing skin health. Given the increasing use of seaweed-based bioactive components in cosmetics, further exploration of P. boergesenii's potential in the cosmetics industry is warranted to leverage its valuable properties.
... Overall, aldobionic acids are gentle to the skin and prevent skin irritation [56]. MBA and CBA could similarly be suitable for sensitive skin or for regenerative care products after harsh treatments like epilation or microdermabrasion [9,56,57]. ...
... Overall, aldobionic acids are gentle to the skin and prevent skin irritation [56]. MBA and CBA could similarly be suitable for sensitive skin or for regenerative care products after harsh treatments like epilation or microdermabrasion [9,56,57]. ...
Article
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Aldobionic acids are sugar acids which consist of a disaccharide with an anomeric acid group. The most famous is lactobionic acid (LBA). LBA is used in many applications such as food and beverages, pharmaceuticals and medicine, cosmetics or chemical processes. During the last decade, all these industries are observing a shift of consumer preferences towards plant-based options. Thus, the biotechnological industry is trying to replace the animal-derived LBA. Maltobionic acid (MBA) and cellobionic acid (CBA) are two stereoisomers of LBA which have emerged as vegan alternatives. However, MBA and CBA face different obstacles related to their industrial production. While traditionally used electrochemical or chemical catalysis often rely on cost intensive and/or hazardous catalysts, novel production methods with microorganisms are still poorly studied. In the first part, this paper discusses both alternatives in terms of their characteristics and applications. In the second part, it reviews the long-studied chemical production and the novel bioproduction methods, which are based on enzymatic and microbial systems. This review concludes with a discussion of future work needed to bring their production to the industrial scale.
... They have been used in dermatology since 1974 as topically effective compounds for skin treatment. The most commonly used AHAs are glycolic, lactic, methyllactic, mandelic, and benzilic acids, as well as malic, tartaric, and citric acids, which are beta hydroxy acids due to the presence of a second carboxyl group (Yu and Van Scott, 2004). The application of AHAs increases water binding capacity as well as skin hydration and skin turgor, and such application offers other anti-aging benefits, making them very attractive to consumers. ...
... Alpha hydroxy acids are also usually included in topical treatments for dry and rough skin, acne, keratoses, wrinkles, photoaging skin, as well as dandruff, callus, and warts (Yu and Van Scott, 2004). The presence of AHAs in cosmetic formulations has increased considerably in the past years. ...
Article
Alpha hydroxy acids (AHAs) are used in dermatology for topical treatment of skin disorders. Some regulatory bodies, including Food and Drug Administration (FDA), recommended labeling cosmetic products with sunburn alerts and proposed limitations regarding concentrations of AHAs in cosmetic products. In addition, The Cosmetic Ingredient Review (CIR) Expert Panel recommended 10% of AHAs in products as the maximal safe concentration. With a rapidly increasing trend of online purchasing of cosmetic products, it is important that their labels convey the necessary warnings and that they be harmonized with regulatory bodies regarding the recommended concentrations of AHAs. The aim of this report was to investigate whether or not the sunburn alert, as well as AHA recommendations mostly used for exfoliating cosmetic products, was visible to consumers during the online purchasing. The compliance with FDA and CIR Expert Panel standards was analyzed in the first 50 cosmetic products obtained after the conducted investigation on the Amazon.com e-commerce company website using the search term “AHA anti-aging.” It was found that exfoliating cosmetic products contained AHAs in a broad range of concentrations, from 2.5 up to 70%. Nineteen out of 50 products contained a concentration of AHAs greater than recommended. Twelve products did not contain any data at all regarding the concentration of AHAs. Sunburn alerts were present in 16 out of 50 analyzed product pages. In conclusion, more efforts should be made in providing users with information and the necessity of protection from potential complications after topical AHAs product treatments
... Delagustin et al. [19] stated that the physical characteristics of LBA had change powder to gel after 6 months of storage; an increase of approximately 12% was ob in the moisture content. The water retention is attributed to the hygroscopic nature [28]. Shendurse and Khedkar [29] have also emphasized that LBA is hygroscop forms a gel containing around 14% water. ...
... Delagustin et al. [19] stated that the physical characteristics of LBA had changed from powder to gel after 6 months of storage; an increase of approximately 12% was observed in the moisture content. The water retention is attributed to the hygroscopic nature of LBA [28]. Shendurse and Khedkar [29] have also emphasized that LBA is hygroscopic and forms a gel containing around 14% water. ...
Article
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The successful development of a lactobionic acid (LBA) bioconversion process on an industrial scale demands the selection of appropriate downstream methodological approaches to achieve product purification once the bioconversion of LBA is completed. These approaches depend on the nature of the substrate available for LBA production, and their necessary implementation could constitute a drawback when compared to the lesser effort required in downstream approaches in the production of LBA obtained by chemical synthesis from refined lactose. Thus, the aim of this research is to separate LBA from an acid whey substrate after bioconversion with Pseudomonas taetrolens. Freeze drying, crystallization, adsorption with activated carbon, microfiltration, centrifugation, and precipitation with 96% (v/v) ethanol were carried out to separate and purify LBA. The closest product to commercial LBA was obtained using precipitation with ethanol, obtaining a white powder with 95 ± 2% LBA concentration. The procedure described in this paper could help to produce LBA on an industrial scale via microbial bioconversion from acid whey, developing a promising biotechnological approach for lactose conversion.
... Typical representatives of AHAs, commonly used as cosmetic active substances (CAS), are malic, citric, tartaric, lactic, succinic and pyruvic acids. These organic acids have epithet of natural CAS or 'fruit' acids and the most of them can be found in plants, as well as in the investigated fruit of wild apple [2][3][4]. ...
... Total content of AHAs in EM corresponded to the amount of added EW (6%). These AHAs, as a good hydration and exfoliant substances [1][2][3][4] potentially, could show positive effects on the skin after application. Therefore, cosmetic cream EM (with concentration of AHAs 0.17%) might be considered for potential use for care of dry skin with hyperpigmentation. ...
Article
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Objective The aim of this study was in vitro and in vivo characterization of cosmetic cream with 6% of wild apple fruit water extract, containing 3.5% of alpha‐hydroxyacids‐AHAs and polyphenolic compounds, stabilized by biodegradable alkyl‐polyglucoside emulsifiers. Methods In vitro characterization of cream included organoleptic and physico‐chemical (pH values and electrical conductivity) analysis, antioxidant activity‐AA estimation (using DPPH test) during 180 days of storage at 22±2°C and determination of cosmetic active substances content‐AHAs (using HPLC analysis). In vivo estimation of skin irritation potential after creams application under occlusion during 24h was investigated employing the biophysical methods on 12 healthy volunteers; hydration efficiency, transepidermal water loss‐TEWL, skin pH, erythema‐EI and melanin index‐MI on 10 healthy volunteers after 28 days of cream application and bleaching efficiency on 10 healthy volunteers after 7 days of cream application after artificially induced skin hyperpigmentation. Results Investigated cosmetic cream was pale beige color, odorless, semi‐solid consistency and homogeneous, with pH values of 6.53±0.14, electrical conductivity above 50 μS/cm and AA of 24.96%RSC after preparation and these characteristics were stable during investigated period. In vivo measurements revealed absence of skin irritation after cream application under occlusion, which was part of it's safety profile. Increase of skin hydration after 14 days of cream application was 17.28±12.23 and after 28 days 21.19±7.59. In addition, in performed experiment TEWL and skin pH values during cream application remained unchanged. Cream application after artificial hyperpigmentation induced decrease of MI (∆MI after 7 days was ‐45.30±18.55) Conclusion Formulated cosmetic cream with 6% of standardized wild apple fruit water extract and stabilized by biodegradable alkyl‐polyglucoside emulsifiers demonstrated good stability, acceptable level of in vitro antioxidant activity, absence of skin irritation after cream application under occlusion and positive effects of cream on human skin after application (hydrating and bleaching effects). All mentioned properties make the cream suitable for possible usage as cosmetic product for preventing the skin damages caused by oxidative stress, for moisturizing the dry skin and bleaching of skin hyperpigmentation. This article is protected by copyright. All rights reserved.
... Carboxylic acids are widely used compounds with important roles in the pharmaceutical, [1] agrochemical and cosmetic industries. [2,3] They are also often used as food additives. [4] There are plethora of methods for the manufacturing of aliphatic and aromatic carboxylic acids. ...
Article
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A scalable electrochemical procedure for the synthesis of carboxylic acids from organic halides has been developed using a spinning cylinder electrode electrochemical reactor. The electrochemical process is based on the reductive dehalogenation of the starting material followed by trapping of the resulting carbanion with CO2. The protocol is compatible both with organic chlorides and bromides and uses inexpensive graphite and stainless steel as electrode materials. As sacrificial metal anodes are avoided, the method can be readily scaled up in flow mode. The procedure is compatible with a wide range of substrates (24 examples), including aryl and alkyl halides as well as heterocyclic compounds. Multigram scale preparations in flow mode have been demonstrated by processing 600 mL of reaction mixture in an electrolyte recirculation setup.
... Previous in vivo studies corroborate the topical use of STS and CA at concentrations indicated in this study; topical STS has been used at concentrations of 25% (w/v) for the treatment of ectopic calcifications, with only 8% of cases documenting skin irritation 16 . Similarly, CA has been used at concentrations of up to 25% for applications targeting rejuvenation of photoaged skin [36][37][38] . In these cases, the compounds were applied daily for several months. ...
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Calcinosis cutis affects 20–40% of patients with systemic sclerosis. This study tests the hypothesis that calcium-chelating polycarboxylic acids can induce calcium dissolution without skin toxicity or irritancy. We compared citric acid (CA) and ethylenediaminetetraacetic acid (EDTA) to sodium thiosulfate (STS) for their ability to chelate calcium in vitro using a pharmaceutical dissolution model of calcinosis (hydroxyapatite (HAp) tablet), prior to evaluation of toxicity and irritancy in 2D in vitro skin models. Resultant data was used to predict therapeutic concentrations for application in a validated 3D skin irritation model (SkinEthic™; EpiSkin SA) and to assay maximal percutaneous absorption. Dissolution performance was further assessed via ability to dissolve a calcified matrix laid down in vitro. Pharmacological dissolution studies identified that polycarboxylic acids were superior to STS in dissolving HAp tablets. In vitro, compounds had little effect on cell numbers at concentrations of < 10 mM. When applied topically to 3D models as near-saturated solutions, chelators were not irritant nor did they impact model structure histologically. CA was the most efficient chelator of calcium salts. This study highlights polycarboxylic acids, particularly CA, as potential therapies to target calcinosis cutis: these should now be investigated in human studies.
... In a previous study, it was reported that citric acid plays a crucial role in increasing skinfold thickness. Ruey et al. (2004) reported that citric acid stimulates the biosynthesis of collagen fibers (Yu and Van Scott 2004). From the molecular docking of the present study, it was confirmed that vitamin C and citric acid have the potential to interact with the collagen protein. ...
Article
ZnO nanoparticles were synthesized using the raw juice of Kaffir lime (Citrus hystrix) fruit bya simple and cost-effective green route and its effects on earthworms, Eudrilus eugeniae, were studied. The kaffir-lime powered ZnO nanoparticles (ZnO:KL) were characterized by X-ray diffraction (XRD), UV-Vis-NIR spectroscopy, Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The filter paper method was adopted to test the toxicity of ZnO:KL. Earthworms (species Eudrilus eugeniae) were exposed to 100 to 1000 mg/L of ZnO:KL in one-step order. During the study period (up to 48 h), no mortality was found in any treatment group. In histological observation, no damage was found in the epidermal layer of earthworm’s skin treated up to 800 mg/L, whereas slight epidermal damage was observed only in 900 and 1000 mg/L treated earthworms. The GC-MS spectrum of the juice of kaffir lime fruit revealed 22 bioactive compounds. The predominantly identified bioactive compounds vitamin C and citric acid were subjected to molecular docking to reveal their binding affinity with collagen – a structural protein providing strength and flexibility of the earthworm’s body. Vitamin C and citric acid bind to the collagen in a favorable orientation with the binding affinity of -4.44 kcal/mol and -4.97 kcal/mol, respectively. Since vitamin C and citric acid are capable of influencing the biosynthesis of collagen, they could prevent skin damage. In sum, the kaffir lime-powered ZnO nanomaterial is less toxic to the earthworm when compared with bare ZnO.
... The skin rejuvenation rate may be boosted by CA, and it can also be used to heal sun damage. 36 Inducing apoptosis in keratinocytes may be related to these activities. ...
Article
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The global market for alpha-hydroxy acids (AHAs) is undergoing significant expansion, propelled by increasing demand for skincare products that address aging and environmental damage. This review focuses on the dermatological applications of AHAs, particularly in cosmetic formulations like chemical peels. We have identified that AHAs, such as glycolic and lactic acids, enhance skin rejuvenation by promoting apoptosis in skin cells, boosting collagen and elastin synthesis, and improving skin texture and luminosity. Our comprehensive analysis reveals a nuanced understanding of AHAs’ effectiveness across various skin types and conditions, demonstrating their broad utility in treating conditions like acne, hyperpigmentation, and photoaging. However, the optimal concentrations for therapeutic efficacy with minimal side effects are yet to be precisely defined, necessitating further research. Regulatory compliance is underscored as essential for the safe application of AHAs in cosmetics, with international guidelines recommending specific concentrations and pH levels to minimize potential skin irritation. In Conclusion, the review highlights the effectiveness of AHAs in cosmetic dermatology, emphasizing the necessity for continued research and rigorous regulatory adherence to maximize their safe and beneficial application worldwide.
... Sugar acids are derived from the oxidation of mono-or disaccharides [2]. Aldobionic acids consist of one monosaccharide (e.g., glucose), chemically linked through a glycosidic bond to a polyhydroxy acid (e.g., gluconic acid) [3]. The most well-known aldobionic acid is lactobionic acid (LBA), which can be obtained by oxidizing lactose [4]. ...
Article
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Cellobionic acid (CBA) can be obtained through the oxidation of cellobiose, the monomer of cellulose. CBA serves as a plant-based alternative to its stereoisomer lactobionic acid, which is used in the pharmaceutical, cosmetic, and food industries. Gluconobacter oxydans is a well-established whole-cell biocatalyst with membrane-bound dehydrogenases (mDH) for regio-specific oxidations. As G. oxydans wildtype cells show low cellobiose oxidation activities, the glucose mDH from Pseudomonas taetrolens was overexpressed in G. oxydans BP9, a multi mDH deletion strain. Whole-cell biotransformation studies were performed with resting cells of the engineered G. oxydans in stirred tank bioreactors. Initial biomass specific cellobionate formation rates increased with increasing cellobiose concentrations up to 190 g L−1, and were constant until the solubility limit. The maximal volumetric CBA formation rates and the oxygen uptake rates increased linearly with the concentration of engineered G. oxydans. This enables the estimation of the maximum biocatalyst concentration limited by the maximum oxygen transfer rate of any bioreactor. Thus, 5.2 g L−1 G. oxydans was sufficient to produce 502 g L−1 CBA with >99% yield in a simple aerobic batch process. The highly concentrated CBA will reduce downstream processing costs considerably after cell separation.
... Alpha hydroxy acids (AHAs) have a wide range of applications. Their exfoliating and moisturizing properties make them useful in dermatology [1][2][3]. Mechanistically, the chelating ability of AHAs enables them to reduce calcium ion concentrations in the epidermis resulting in disruption of cellular adhesions and exfoliation [4]. Topical lactic acid solutions have shown to affect the epidermis and dermis and increase cell turnover based on the concentration of lactic acid in the solution [2]. ...
Article
Enantioseparation of alpha-hydroxy acids is essential since specific enantiomers of these compounds can be used as disease biomarkers for diagnosis and prognosis of cancer, brain diseases, kidney diseases, diabetes, etc., as well as in the food industry to ensure quality. HPLC methods were developed for the enantioselective separation of 11 α\mathrm{\alpha }-hydroxy acids using a superficially porous particle–based teicoplanin (TeicoShell) chiral stationary phase. The retention behaviors observed for the hydroxy acids were HILIC, reversed phase, and ion-exclusion. While both mass spectrometry and UV spectroscopy detection methods could be used, specific mobile phases containing ammonium formate and potassium dihydrogen phosphate, respectively, were necessary with each approach. The LC–MS mode was approximately two orders of magnitude more sensitive than UV detection. Mobile phase acidity and ionic strength significantly affected enantioresolution and enantioselectivity. Interestingly, higher ionic strength resulted in increased retention and enantioresolution. It was noticed that for formate-containing mobile phases, using acetonitrile as the organic modifier usually resulted in greater enantioresolution compared to methanol. However, sometimes using acetonitrile with high ammonium formate concentrations led to lengthy retention times which could be avoided by using methanol as the organic modifier. Additionally, the enantiomeric purities of single enantiomer standards were determined and it was shown that almost all standards contained some levels of enantiomeric impurities.
... Obserwacje Van Scotta i wsp. pokazują natomiast, że niskie stężenia AHA zmniejszają spoistość korneocytów w dolnych warstwach naskórka [25]. Rozbieżność w wynikach może wynikać z faktu, że probanci mieli różny rodzaj skóry. ...
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Up to now, research studies have compared various peeling substances affecting the skin, without taking into account the parameters responsible for the penetration and potency of the compounds. The aim of this study was to analyze the effects of lactic acid and mandelic acid on hydration, melanin, sebaceous gland activity and the stratum corneum barrier. Equal concentrations of chemical peels, similar pH of the solutions, and the base enabled comparison of results. A series of treatments with lactic acid resulted in a decrease in transepidermal water loss, an increase in hydration levels and a reduction in sebaceous gland activity, as well as a significant drop in melanin levels. Mandelic acid applied in a series of four treatments resulted in a noticeable improvement in the appearance of the epidermis. The activity of the sebaceous glands also decreased significantly. The use of both, a series and a single treatment with mandelic acid, strengthened the epidermal barrier. Comparing a series of treatments and a single procedure it was found that the value of transepidermal water loss increased. The study demonstrated that whereas many carboxylic acids exhibit similarities, they also possess notable distinctions in their topical effects and medicinal applications.
... Vitamin C is a polyhydroxy compound with a structure similar to glucose [6]. The two adjacent enol hydroxyl groups on the 2nd and 3rd positions in the molecule are easily dissociated to release H + , so it has the property of acid, also known as L-ascorbic acid. ...
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Methods: The study included 5145 adults (age ≥ 30 years) with periodontitis as a dichotomous variable and daily intake of vitamin C as a continuous variable. Multiple sets of covariates, such as age, sex, number of flossing, etc., were selected. Using EmpowerStats version 3.0, multivariate logistic regression analysis and hierarchical analysis were performed on the data, and curve fitting graphs were made. Results: There were no statistically significant differences (P > 0.05) between the four dietary vitamin C intake groups (quartiles, Q1-Q4) and covariates (drinking alcohol and hypertension). The low VC intake group (Q1) was more prone to periodontitis than Q2, Q3, and Q4 (all OR < 1.00). A threshold nonlinear association was found between vitamin C (mg) log10 transformation and periodontitis in a generalized additive model (GAM) (P = 0.01). Conclusion: The relationship between dietary vitamin C intake and the likelihood of periodontitis was non-linear. The smallest periodontitis index occurred when dietary vitamin C intake was 158.49 mg. Too little or too much vitamin C intake increases periodontitis.
... The quantitative assessment of organic acids levels in human body fluids can supply an initial identification of diverse ailments. They also find an application in pharmaceuticals (as solubilisers, prodrugs, bioprecursors, and pharmacophores) [52,55], cosmetics (to clean pores, improve the skin texture, or in acne treatment) [52,56], as well in the production of air fresheners, deodorants, and perfumes [52,57]. As presented in the Results section, the method of carboxylic acids' extraction with the use of the NaHCO3 test did not allow for an indication of the presence of these chemicals in the examined plant extracts. ...
Article
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In recent years, there has been an increased interest in products of natural origin. The extraction procedure of bioactive compounds from plant matrices is a crucial step in the development of useful new bioproducts for everyday life. The utilisation of analyses enabling the rapid identification of the presence of a given group of compounds can be helpful in the early stages of the development of new products in order to save time and reduce costs. Within this article, we have presented a comparison of different, accessible methods for the identification of various bioactive compounds, e.g., saponins, carboxylic acids, oils and fats, proteins and amino acids, steroids, and alkaloids in plant-based extracts. Additionally, the multielemental composition of extracts was also examined. The applied methods allowed for confirmation of the presence of biologically active compounds in bio-products obtained by ultrasound-assisted extraction. At a later stage, these procedures should be supplemented by advanced analytical techniques in order to determine the plant chemicals’ content qualitatively and quantitatively.
... Vitamin C is a polyhydroxy compound with a structure similar to glucose [6]. The two adjacent enol hydroxyl groups on the 2nd and 3rd positions in the molecule are easily dissociated to release H + , so it has the property of acid, also known as L-ascorbic acid. ...
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Background The purpose of this study was to investigate whether periodontitis is associated with dietary vitamin C intake, using data from The National Health and Nutrition Examination Survey (NHANES) 2009–2014. Methods The study included 5145 adults (age ≥ 30 years) with periodontitis as a dichotomous variable and daily intake of vitamin C as a continuous variable. Multiple sets of covariates, such as age, sex, number of flossing, etc., were selected. Using EmpowerStats version 3.0, multivariate logistic regression analysis and hierarchical analysis were performed on the data, and curve fitting graphs were made. Results There were no statistically significant differences ( P > 0.05) between the four dietary vitamin C intake groups (quartiles, Q1–Q4) and covariates (drinking alcohol and hypertension). The low VC intake group (Q1) was more prone to periodontitis than Q2, Q3, and Q4 (all OR < 1.00). A threshold nonlinear association was found between vitamin C (mg) log10 transformation and periodontitis in a generalized additive model (GAM) ( P = 0.01). Conclusion The relationship between dietary vitamin C intake and the likelihood of periodontitis was non-linear. The smallest periodontitis index occurred when dietary vitamin C intake was 158.49 mg. Too little or too much vitamin C intake increases periodontitis.
... Une classe d'acides organiques avec une contribution importante dans le domaine cosmétique sont les alpha-hydroxyacides (AHA). Les acides citrique, malique, tartrique, lactique et glycolique font partie de cette catégorie et sont largement utilisés dans les cosmétiques à des fins telles que débloquer/nettoyer les pores, améliorer la texture de la peau, blanchir, antirides ou traitement de l'acné (Yu et Van Scott, 2004). De plus, dans l'industrie cosmétique, les acides gras représentent la classe des acides carboxyliques reconnus pour leur utilité depuis que leurs sels hydrosolubles (savons) ont été utilisés comme nettoyants depuis l'antiquité et comme tensioactifs les plus utiles (Lukic et al., 2016). ...
Thesis
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Les composés organiques semi volatiles (COSVs) sont rejetés continuellement dans l’atmosphère, ce qui rend leur analyse importante pour évaluer la qualité de l'air ambiant. Le nouveau matériau comme la mousse NMC@SiC® a été choisi comme échantillonneur passif dans l’air. Ce mousse de Carbure de Silicium (SiC) greffé présente des propriétés (telles que surface spécifique et porosité) qui en font un adsorbant mixte permettant de piéger phase gazeuse et phase particulaire. La campagne a été réalisée sur six sites à Strasbourg et alentours entre juin 2018 et fin février 2020 et à côté du site au centre de Strasbourg, un échantillonneur actif est exploité en parallèle. Les composés ciblés dans ce travail étaient les HAP, PCB, les pesticides organochlorés et non organochlorés, les phénols, les acides et les amines. Une couplage de méthode analytique entre ASE, SPE et SPME a été développé et optimisée pour ces composés. La méthode optimisée permet d’obtenir de faibles LOD et LOQ pour les composés recherchés. Le prélèvement réalisé par l’échantillonneur passif et actif permet de déterminer les débits d’échantillonnage qui sont comparables aux valeurs publiés dans la littérature pour la mousse PUF et la résine XAD-2. Les résultats de campagnes obtenues de chaque site sont convertis en ng m-3, ce qui permet de montrer l’efficacité de cette mousse. Elle peut adsorber un grand nombre de composés plus volatils comme des pesticides, des composés moins volatils comme les HAPs et PCBs lourds, et avec son hydrophobicité faible, elle permet de piéger des composés polaires (phénols et acides). De plus, les compagnes ont montré les tendances de concentrations de composés sur chaque site étudiés et les différentes variations temporelles.
... Their application fields are disparate and include medicine, food, pharmaceutical and other industries (production of polymers, coatings, and adhesives) [16]. In the food industry, they can be used as additives to lend specific organoleptic properties or stability to the food, although some type of acids, such as citric acid, tartaric acid, or malic acid, occur naturally in foods such as fruit [17]. Amines are nitrogen-bearing compounds obtained by microbial decarboxylation of amino acids. ...
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Arsenic is a well-known contaminant present in different environmental compartments and in human organs and tissues. Inorganic As(III) represents one of the most dangerous arsenic forms. Its toxicity is attributed to its great affinity with the thiol groups of proteins. Considering the simultaneous presence in all environmental compartments of other common functional groups, we here present a study aimed at evaluating their contribution to the As(III) complexation. As(III) interactions with four (from di- to hexa-) carboxylic acids, five (from mono- to penta-) amines, and four amino acids were evaluated via experimental methods and, in simplified systems, also by quantum-mechanical calculations. Data were analyzed also with respect to those previously reported for mixed thiol-carboxylic ligands to evaluate the contribution of each functional group (-SH, -COOH, and -NH2) toward the As(III) complexation. Formation constants of As(III) complex species were experimentally determined, and data were analyzed for each class of ligand. An empirical relationship was reported, taking into account the contribution of each functional group to the complexation process and allowing for a rough estimate of the stability of species in systems where As(III) and thiol, carboxylic, or amino groups are involved. Quantum-mechanical calculations allowed for the evaluation and the characterization of the main chelation reactions of As(III). The potential competitive effects of the investigated groups were evaluated using cysteine, a prototypical species possessing all the functional groups under investigation. Results confirm the higher binding capabilities of the thiol group under different circumstances, but also indicate the concrete possibility of the simultaneous binding of As(III) by the thiol and the carboxylic groups.
... Further studies may strengthen the pool of evidence by using reproducible evidence-based methods to assess the efficacy of these preparatory agents at each stage of the sterilization protocol (at-home decolonization, presurgical preparatory decolonization, and sterile surgical preparation). In addition, these studies should aim to correlate agent use to clinical infection with appropriate follow-up duration, analyzing other treatment types (combinations of CHG and BPO or novel agents such as PCA), 18,19,38,46,47 assessing specific application methods (frequency, concentration, and timing), and culturing sites from the deep tissues and dermis. ...
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Background Cutibacterium acnes (C. acnes) is a commensal intradermal microorganism that is commonly isolated at revision shoulder arthroplasty. Standard practice chlorhexidine gluconate (CHG) skin preparation agents have limited effectiveness at eradicating C. acnes in the dermis. Benzoyl peroxide (BPO) has demonstrated effectiveness against C. acnes. This meta-analysis compares the efficacy of at-home shoulder decolonization prior to surgery using CHG versus BPO to reduce shoulder C. acnes burden. Methods A PRISMA systematic review. PubMed and MEDLINE databases were searched for studies evaluating effects of CHG and BPO in reducing C. acnes at the shoulder. Trial results were extracted and pooled using a random effects model, separating data from randomized controlled trials (RCTs) and non-RCTs. Methodologic quality of studies was assessed using the Cochrane Risk of Bias Assessment Tools. Results Ten studies (589 patients) were included. RCTs showed that both BPO and CHG led to significant reductions in culture positivity compared to negative controls (risk ratio (RR) with 95% confidence interval (CI) = 0.20 [0.13, 0.30] (p < 0.0001) and 0.46 [0.37, 0.57] (p < 0.0001), respectively). Non-RCT data demonstrated similar results comparing BPO and CHG to the control (RR with 95% CI = 0.34 [0.21, 0.57] (p < 0.0001) and 0.31 [0.20, 0.49] (p < 0.0001), respectively). Comparing BPO and CHG, RCT data showed a significant reduction in culture positivity with BPO (RR with 95% CI = 0.46 [0.27, 0.77] (p < 0.009)). Of RCTs, five were low and one was of moderate risk of bias. Of non-RCTs, three were low while one had moderate risk of bias. Conclusions This review demonstrated that preoperative CHG and BPO can reduce C. acnes at the shoulder. However, BPO exhibits greater efficacy than CHG, potentially due to the compound’s ability to penetrate the dermis. BPO is a simple and economical agent that may reduce joint exposure to C. acnes in shoulder surgery.
... According to our results, however, it was shown that Lactic acid only negligibly scavenges the DPPH radical-in the range from 0.0 ± 0.0 to 2.5 ± 2.9% (Fig. 2). This result is consistent with a study by Yu and Van Scott (2004), who showed that Lactic acid has the lowest antioxidant activity among α-hydroxy acids. We also hypothesize that in some postbiotics, especially in the genus Lactococcus, the production of enzymes such as superoxide dismutase prevents the accumulation of free radicals (Feng and Wang, 2020). ...
Article
The importance of probiotics for the internal and external human microbiota has already been scientifically confirmed. As these are viable bacteria, the direct dermal use of them through mass-produced cosmetics is impossible. For these purposes, postbiotics—substances derived from probiotics through fermentation processes—appear to be promising. Two postbiotics have been investigated in vitro for their protective ability against free radicals and UV radiation compared to conventional synthetic chemicals. Lactococcus Ferment Lysate and Bifida Ferment Lysate in 5% aqueous solution and 100% concentrate were able to scavenge from 0.15 to 54.2% and 7.0 to 71.0%, respectively, of 2,2-diphenyl-1-picrylhydrazyl radical. L. Ferment Lysate in the emulsion, the composition of which is a reference in testing the effectiveness of sunscreen products with a low SPF value, showed an absorption capacity in the UVB region (SPF 4.75) comparable to the standard chemical UV filter Homomenthyl salicylate (SPF value of 4.45) and in the UVA region better than this standard. The UV absorption ability of B. Ferment Lysate was negligible. Postbiotics B. Ferment Lysate and L. Ferment Lysate are beneficial natural active ingredients for the skin protection against free radicals and L. Ferment Lysate also against UVB + UVA radiation.
... For example, the adjustment of pH 4 of W/O emulsions, which was more effective than pH 5.8 emulsion, in research done by Kilic et al. and Angelova-Fischer et al. was accomplished by the mixture of glycolic acid and ammonia buffer. Glycolic acid is a well-established cosmetic and dermatologically active substance used for topical treatment of various skin conditions and disorders with a moisturizing, exfoliating and even anti-aging effect, depending on the used concentration [131]. Without any intention to disprove the obtained results, the possible contribution of the entrapped fraction of glycolic acid which could be slowly released from the inner phase of the applied pH 4 W/O emulsion should also be considered. ...
Article
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Acidic pH of the skin surface has been recognized as a regulating factor for the maintenance of the stratum corneum homeostasis and barrier permeability. The most important functions of acidic pH seem to be related to the keratinocyte differentiation process, the formation and function of epidermal lipids and the corneocyte lipid envelope, the maintenance of the skin microbiome and, consequently, skin disturbances and diseases. As acknowledged extrinsic factors that affect skin pH, topically applied products could contribute to skin health maintenance via skin pH value control. The obtained knowledge on skins’ pH could be used in the formulation of more effective topical products, which would add to the development of the so-called products ‘for skin health maintenance’. There is a high level of agreement that topical products should be acidified and possess pH in the range of 4 to 6. However, formulators, dermatologists and consumers would benefit from some more precise guidance concerning favorable products pH values and the selection of cosmetic ingredients which could be responsible for acidification, together with a more extensive understanding of the mechanisms underlaying the process of skin acidification by topical products.
... 3-Hydroxyacids (3-HAs) or β-hydroxyacids are a type of carboxylic acids that contain a hydroxyl group at the β-position of the aliphatic carbon atom (Yu and Van Scott 2004). 3-HAs are biosynthesized in various groups of organisms (i.e., bacteria, yeast, fungi, and microalgae) in which they serve as intermediates of the β-oxidation pathway (Jin et al. 1992;Matsumoto and Nagashima 1984). ...
Thesis
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Due to various social, environmental, and technological issues associated with petro-based chemical processes, bio-based production using microbial cell factories has been recognized as a modern biotechnology for more renewable, sustainable, and clean manufacturing of chemical compounds. With respect to conventional chemical transformation, such in vivo biotransformation offers a substantial processing simplicity and technological leverage, particularly for the production of structurally complex compounds, by carrying out intricate and multi-step reactions with high specificity via one-pot reaction. Among numerous microbial cell factories, bacterium Escherichia coli is the most popular and user-friendly workhorse primarily due to its genetic amenability and well-developed bioprocessing strategies. While wild-type E. coli is not a native producer for many chemical products, technological advances in synthetic biology, genetic engineering, protein engineering, and metabolic engineering have offered a promise for extensive tailoring of E. coli strains with virtually any types of biosynthetic capacity. In this thesis study, we integrate several strain and bioprocess engineering strategies for rewiring of carbon flux around one of tightly-regulated central metabolic branch-points (i.e., node of succinyl-CoA) to enhance precursor supply for effective biosynthesis of three particular value-added chemicals, i.e., propionate, 3-hydroxyvalerate (3-HV), and 5-aminolevulinate (5-ALA), in E. coli host strains. In our initial study, we use our previously-derived propanologenic (i.e., 1-propanol- producing) bacterium E. coli strain with an activated genomic Sleeping beauty mutase (Sbm) operon for heterologous propionate production. Note that activated Sbm pathway branches out of the tricarboxylic acid (TCA) cycle at the succinyl-CoA node to form propionyl-CoA and its derived metabolites of 1-propanol and propionate. We first investigate the sensitivity around succinyl-CoA node by targeting multiple genes encoding enzymes that are involved in reactions contributing to carbon flux toward this node. These particular reactions are from three TCA cycle routes, i.e., i.e., oxidative TCA cycle, reductive TCA branch, and glyoxylate shunt. Effective blocking of oxidative TCA cycle and deregulating glyoxylate shunt has led to the secretion of roughly 30.9 g l-1 of propionate with minimal byproduct formation upon fed-batch cultivation our engineered strain under aerobic conditions. To best of our knowledge, the propionate titer reached in this study is the highest reported in E. coli from single structurally-unrelated carbon source (i.e., glycerol). For the subsequent part of our thesis, we further engineer our Sbm-activated E. coli strain by constructing a 3-hydroxyacid pathway for the production of heterologous long (odd)-chain 3- HV. The development of this particular strain involved modular construction of 3-HV biosynthetic pathway by establishing efficient Claisen condensation, reduction reaction, and CoA removing capabilities. In addition to strain engineering, various biochemical strategies (i.e., cultivation temperature, carbon sources, and aeration) were investigated for high secretion of approximately 3.71 g l-1 3-HV under vent-cap shake-flask cultivation. We used the information obtained from previous sections to scale-up our 3-HV production under batch and fed-batch bioreactor system. Herein, we used bioprocess engineering approach to enable more carbon flux toward succinyl-CoA node (and ultimately propionyl-CoA) by simultaneously inhibiting oxidative TCA cycle and deregulating glyoxylate shunt. With these developed strategies, we demonstrated effective cell growth, minimum secretion of byproducts, and high 3-HV production (up to 10.6 g l-1) in aerobic fed-batch culture. As far as we are aware, the level of 3-HV reached in this study is the highest reported for any microbial strain thus far. In our final study, we investigate the feasibility of our developed TCA cycle engineering strategy for effective production of 5-ALA, an endogenous non-proteinogenic amino acid. We first manipulated the non-native Shemin part of heme biosynthetic pathway by downregulating essential 5-ALA-consuming reaction using Clustered Regularly Interspersed Short Palindromic Repeats interference (CRISPRi), thus considerably preserving intracellular pool of this target metabolite. As Shemin pathway synthesized 5-ALA in a one-step reaction catalyzed by molecular fusion of succinyl-CoA and glycine, formation of 5-ALA was further improved by channeling more carbon toward succinyl-CoA precursor in TCA cycle, reaching high titer of 6.93 g l-1 under aerobiosis. To best of our knowledge, the consolidated strain and bioprocess engineering strategy reported in this study represents one of the most effective and economical bio-based production of 5-ALA in E. coli from single carbon source. Collectively, this thesis attempts to highlight the importance and applicability of integrated strain engineering and bioprocessing strategies for enhanced bio-based production of industrially valuable products. Harnessing this enhanced carbon flux toward succinyl-CoA node and employing various modular chain elongation and pathway enzymes can open the avenue for the controlled production of various other valuable succinyl-CoA-derived chemicals.
... Antibacterial potency as a function of solution pH. Glycolic acid is the smallest alpha hydroxy acid and consists of a carboxylic acid functional group along with a hydroxyl functional group at the neighboring α-carbon position 26 (Fig. 1a). Only the carboxylic acid group is ionizable in biologically relevant pH conditions and glycolic acid exists in an equilibrium between two molecular states: (1) nonionic when the carboxylic acid is protonated at low pH conditions and (2) anionic when the carboxylic acid is deprotonated at high pH conditions. ...
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Glycolic acid is the smallest alpha hydroxy acid and widely used for skincare applications, including to treat acne vulgaris. Oftentimes, high concentrations of glycolic acid (~20–50 vol%) are incorporated into chemical peels to reduce acne-related inflammation while there is an outstanding need to determine to what extent glycolic acid can potently inhibit Cutibacterium acnes (formerly known as Propionibacterium acnes), which is a Gram-positive bacterium implicated in acne pathogenesis. Herein, we report that glycolic acid exhibits pH-dependent antibacterial activity against C. acnes and mechanistic studies identified that the nonionic form of glycolic acid is more active than the anionic form. The degree of antibacterial activity, including minimum bactericidal concentration (MBC), of glycolic acid was evaluated in the pH range of 3 to 4.5, and the greatest potency was observed at pH 3. In light of skincare formulation needs, we selected the pH 3.5 condition for further testing and determined that glycolic acid kills C. acnes cells by disrupting bacterial cell membranes. While most conventional treatments involve high concentrations of glycolic acid (>20%), our findings support the potential of developing anti-acne formulations with glycolic acid concentrations as low as 0.2% and with pH conditions that are suitable for over-the-counter applications.
... As an approach based on mild bioprocesses, industrial biotechnology is clean, environmentally friendly, and has potential to revolutionize the chemical industry, which often uses severe process conditions, contributing to a more sustainable chemical industry [1]. In this scenario, lactobionic acid stands out due to its high commercial value and important applications as part of drug delivery system, as a component of solutions used to preserve human organs to be transplanted, and even as an active principle for anti-aging cosmetics [2][3][4][5][6]. In brief, lactobionic acid can be obtained by the chemical oxidation of lactose [7,8] or by bioprocesses using Pseudomonas [9] or Zymomonas mobilis [10][11][12]. ...
Article
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Lactobionic acid and sorbitol are produced from lactose and fructose in reactions catalyzed by glucose–fructose oxidoreductase and glucono-δ-lactonase, periplasmic enzymes present in Zymomonas mobilis cells. Considering the previously established laboratory-scale process parameters, the bioproduction of lactobionic acid was explored to enable the transfer of this technology to the productive sector. Aspects such as pH, temperature, reuse and storage conditions of Ca-alginate immobilized Z. mobilis cells, and large-scale bioconversion were assessed. Greatest catalyst performance was observed between pH range of 6.4 and 6.8 and from 39 to 43 °C. The immobilized biocatalyst was reused for twenty three 24-h batches preserving the enzymatic activity. The activity was maintained during biocatalyst storage for up to 120 days. Statistically similar results, approximately 510 mmol/L of lactobionic acid, were attained in bioconversion of 0.2 and 3.0 L, indicating the potential of this technique of lactobionic acid production to be scaled up to the industrial level.
... Glycolic acid is a weak acid (4). The pH of the airway surface liquid is endogenously regulated by acid and base secretion mechanisms (43,44). ...
Article
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Background/aim: The use of glycolic acid is present in a variety of consumer products, including medicines, cleaners, cosmetics, and paint strippers. It has recently led to concerns about toxicity from inhalation exposure. Herein, the pulmonary toxicity of glycolic acid was investigated in rats. Materials and methods: We conducted acute (~458 mg/m3) and sub-acute (~49.5 mg/m3) inhalation tests to identify the potential toxicities of glycolic acid. Results: Inhalation exposure to glycolic acid in the acute and subacute inhalation tests did not cause any specific changes in clinical examinations, including body weight, organ weight, hematology, serum biochemistry, and histopathology. The polymorphonuclear neutrophils (PMNs) and inflammatory cytokines in Bronchoalveolar lavage fluid (BALF) increased in rats exposed to single and repeated inhalations. In the sub-acute test, the changes induced by glycolic acid were minor or returned to normal during the recovery period. Conclusion: The No Observed Adverse Effect Concentration (NOAEC) for the nasal and pulmonary toxicity of glycolic acid was determined to be over 50 mg/m3 at the end of a 28-day inhalation test in male rats.
... Specifically, butyrate has been of particular interest for its potential pharmaceutical effects in treating leukemia, sickle cell anemia, and alopecia (Dwidar et al. 2012). Furthermore, 3-hydroxyalkanoates (or β-hydroxyalkanoates) are aliphatic carboxylates with a hydroxyl group attached to the β-carbon (Yu and Van Scott 2004). They are fine chemicals that can act as building blocks for the synthesis of several antibiotics, vitamins, and pheromones Perez-Zabaleta et al. 2016;Ren et al. 2010). ...
Article
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Being the most abundant renewable organic substance on Earth, lignocellulosic biomass has acted as an attractive and cost-effective feedstock for biobased production of value-added products. However, lignocellulosic biomass should be properly treated for its effective utilization during biotransformation. The current work aimed to demonstrate biobased production of butyrate and 3-hydroxybutyrate (3-HB) in engineered Escherichia coli using pretreated and detoxified aspen tree (Populus tremuloides) wood chips as the feedstock. Various bioprocessing and genetic/metabolic factors limiting the production of cellulosic butyrate and 3-HB were identified. With these developed bioprocessing strategies and strain engineering approaches, major carbons in the hydrolysate, including glucose, xylose, and even acetate, could be completely dissimilated during shake-flask cultivation with up to 1.68 g L⁻¹ butyrate, 8.95 g L⁻¹ 3-HB, and minimal side metabolites (i.e., acetate and ethanol) being obtained. Our results highlight the importance of consolidating bioprocess and genetic engineering strategies for effective biobased production from lignocellulosic biomass.
... Citric, malic, tartaric, and lactic and glycolic acids are part of this category and are extensively used in cosmetics for purposes such unblock/clean pores, improve the skin texture, whitening, anti-wrinkle, or acne treatment. Also, carboxylic acids represented by aldobionic acids (ABAs), retinoic acids, vitamin C, and azelaic acid are most efective in providing antioxidant and anti-aging protection, as well as improving moisture-retention [5,6]. The carboxylic acid-based esters are the derivatives most well-known for their lavors and fragrances and are widely used in various applications including perfumes, deodorant, and air fresheners. ...
... In addition, CA at a concentration of 20% can increase the thickness of the epidermis and the amount of glycosaminoglycans in sun-damaged skin. CA has also been found to increase the skin renewal rate [26] and treat sun-damaged skin. These functions may correlate with promoting keratinocyte apoptosis. ...
Article
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AHAs are organic acids with one hydroxyl group attached to the alpha position of the acid. AHAs including glycolic acid, lactic acid, malic acid, tartaric acid, and citric acid are often used extensively in cosmetic formulations. AHAs have been used as superficial peeling agents as well as to ameliorate the appearance of keratoses and acne in dermatology. However, caution should be exercised in relation to certain adverse reactions among patients using products with AHAs, including swelling, burning, and pruritus. Whether AHAs enhance or decrease photo damage of the skin remains unclear, compelling us to ask the question, is AHA a friend or a foe of the skin? The aim of this manuscript is to review the various biological effects and mechanisms of AHAs on human keratinocytes and in an animal model. We conclude that whether AHA is a friend or foe of human skin depends on its concentration. These mechanisms of AHAs are currently well understood, aiding the development of novel approaches for the prevention of UV-induced skin damage.
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Asam glikolat (AG) digunakan untuk mengatasi photoaging, namun menyebabkan rasa menyengat pada kulit. Kompleks molekular asam glikolat-kitosan (AG-KS) dapat mengatasi masalah tersebut namun berpotensi memperbesar ukuran partikel sehingga dibentuk sediaan nanoemulsi dengan Cremophor RH 40 sebagai surfaktan. Nanoemulsi diharapkan meningkatkan bioavailabilitas bahan aktif dengan meningkatkan luas permukaan dan Cremophor RH 40 mendukung peningkatkan permeabilitas membran dengan menurunkan tegangan antarmuka. Konsentrasi Cremophor RH 40 optimum diperlukan untuk mencapai kondisi tersebut. Tujuan penelitian ini untuk memperoleh formula optimum nanoemulsi kompleks molekular AG-KS dengan variasi konsentrasi Cremophor RH 40 menggunakan metode desain faktorial. Kompleks AG-KS (1:1) disonikasi selama 10 menit. Nanoemulsi dibuat dengan variasi Cremophor RH 40 10%, 20%, 30%. Sediaan diuji organoleptik, homogenitas, tipe emulsi, pH, viskositas, daya sebar, daya lekat, ukuran partikel, indeks polidispersitas (PI), dan potensial zeta. Data dianalisis menggunakan multilevel categoric-one factor. Sediaan berwarna putih, tekstur lembut, homogen, tidak beraroma, dengan tipe emulsi minyak dalam air. pH rata-rata sediaan 3,9 ±0,00 memenuhi persyaratan BPOM, viskositas dan daya lekat meningkat dengan meningkatnya variabel bebas, sedangkan daya sebar menurun. Hasil ukuran partikel dari ketiga formula di bawah 400 nm. Indeks polidispersitas menunjukkan monodisperse (<0,6) dengan potensial zeta <30 mV. Hasil formula optimum menggunakan desain faktorial didapatkan F2 dengan nilai desirability 0,608. Cremophor RH 40 konsentrasi 20% optimal digunakan pada nanoemulsi kompleks molekuler AG-KS.
Article
Objective: The current study evaluated the relationship between serum vitamin C and chronic kidney disease. Methods: The database from the National Health and Nutrition Examination Survey (NHANES, 2017-2018) was used to perform a cross-sectional study. Multivariate logistic regression was performed to analyze the relationship between serum vitamin C and chronic kidney disease (CKD), and stratified analysis by sex was performed to assess whether there were sex differences in the association between serum vitamin C and CKD. Results: Before stratified analysis, multivariate logistic regression showed that serum vitamin C was negatively associated with CKD in all models (All OR > 1, P<0.05), the risk of CKD decreased by one quantile increase in serum vitamin C (P for trend<0.001) and low vitamin C status was associated with a higher risk of CKD (All OR > 1, P<0.05). Stratified analyses by sex showed that the association between serum vitamin C and CKD remained negative in men, but not in women. Conclusion: There were a negative correlation between serum vitamin C and CKD, low levels of vitamin C were associated with a higher risk of CKD, and these associations were only found in men, but not in women.
Article
The complexes of europium(III) ions in binary and ternary systems with α-hydroxy acids and biogenic amine - spermine were investigated. Studies have been performed in aqueous solution using the potentiometric method with computer analysis of the data. Analysis of the equilibrium constants of the reactions and spectroscopic data have allowed us to determine the type of coordination and effectiveness of the carboxyl groups in the process of complex formation in the systems studied. Furthermore, the results confirmed the occurrence of non-covalent interactions of protonated spermine with coordinated α-hydroxy acid. The effect of biogenic polyamine concentration was clearly confirmed, and their influence on the stability and coordination mode of ternary complexes was found.
Article
Background: Wild apple fruit are rich source of bioactive substances, which can be potentially used for a production of dermocosmetic products. Aim: The aim of study was in vitro and in vivo investigation of standardized wild apple fruit extracts (obtained by purified water and maceration-EM, percolation-EP, Soxhlet extraction-ES and ultrasonic extraction-EU) and dermocosmetic creams of o/w type containing 6%, 12% and 15% of extract-EU, as extract with the best content of polyphenolic compounds (CE6, CE12, CE15, respectively), in order to determine the optimal concentration of the extract, which manifests the best effect on the biophysical characteristics of the skin after application. Methods: Content of polyphenolic substances-PP was investigated using HPLC analysis, while in vitro biological activity was examined on L929 fibroblasts using MTT viability test. In vivo efficacy included screening and comparation of skin hydration potential, transepidermal water loss-TEWL and skin pH after 28 days of creams application on healthy volunteers' skin. Results: Content of identified PP was the highest in the extract-EU (2001.57±0.87 mgPP/100gEU) and satisfactory in cream-CE6 (53.83±0.23 mgPP/100gCE6). Procyanidin B2 was the most common PP. Biological activity analysis showed that extract-EU could be considered as non-cytotoxic for fibroblasts in examined concentrations. In vivo investigation revealed an increase of skin hydration (after 28 days ΔEC was 21.19±7.59, 26.71±7.94 and 29.60±10.95 for CE6, CE12 and CE15, respectively), with unchanged TEWL and skin pH values. Conclusion: Obtained results indicate that wild apple fruit extract represents a valuable source of bioactive substances, with good hydration effects of creams on human skin (effect of creams increased proportionally to the increase of concentration of incorporated extract), so it might be considered as a great potential for application in dermocosmetic industry.
Article
Improvement in skin luminosity and dyschromia such as post‐inflammatory hyperpigmentation (PIH) and actinic photodamage are leading causes for cosmetic consultation. Formulation of topical at home treatment are challenging, using a range of modalities, to help hinder or prevent inflammatory mediators without further irritating the skin. Glycolic acid is a known antioxidant, in various free acid levels it has been introduced as a topical therapy aimed at reducing pigmentation and improving skin texture, tone, and luminosity. Methods In a 12‐week clinical study, a novel, topical facial emulsion containing 10% Glycolic Acid, 2% Phytic acid, and Soothing Complex in emulsion was evaluated for its effectiveness in treating skin quality in American female volunteers with Fitzpatrick skin types II‐IV. Efficacy evaluations were performed at pre‐treatment baseline, weeks 2, 4, 8, and 12, and included expert clinical grading, and self‐assessment questionnaires. Cutaneous tolerability was also evaluated by assessing subjective and objective irritation of the treatment area. Results Significant improvement in the appearance of skin PIH, hyperpigmentation, texture, and tone homogeneity was observed beginning at week 4 and continued through week 12. Conclusions The findings suggest that the test product is well suited for at home skincare. It was both well‐tolerated and an effective treatment option for addressing hyperpigmentation and overall skin luminosity.
Article
Ten new xanthone derivatives have been designed and synthesized for their potential antibacterial activity. All compounds have been screened against Staphylococcus epidermidis strains ATCC 12228 and clinical K/12/8915. The highest antibacterial activity was observed for compound 3: 5‐chloro‐2‐((4‐(2‐hydroxyethyl)piperazin‐1‐yl)methyl)‐9H‐xanthen‐9‐one dihydrochloride, exhibiting MIC of 0.8 µg/ml against ATCC 12228 strain, compared to linezolid (0.8 µg/ml), ciprofloxacin (0.2 µg/ml) or trimethoprim and sulfamethoxazole (0.8 µg/ml). For the most active compound 3, genotoxicity assay with use of Salmonella enterica serovar Typhimurium revealed safety in terms of genotoxicity at concentration 75 µg/ml and antibacterial activity against Salmonella at all higher concentrations. A final in silico prediction of skin metabolism of compound 3 seems promising, indicating stability of the xanthone moiety in the metabolism process. logP = 3.24. mV = 326 Å3. TPSA = 56.91 Å2 MIC Staphylococcus epidermidis ATCC 12228 strain = 0.8 µg/ml MIC Staphylococcus epidermidis K/12/8915 strain = 50 µg/ml.
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Pyruvic acid has been considered as an important agent for peel because of its important ability to weaken keratinocytes cohesion and generates epidermolysis with no systemic toxicity. Given that, it can be used as a superficial to medium-depth peeling to approach inflammatory acne, moderate acne scars, oily skin, folliculitis, photoaging, and actinically damage skin.
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The chemical configuration of the lactobionic acid (LBA) evidences its potential properties, among which the antioxidant, antimicrobial, and chelating activities stand out in the literature. However, few studies aim at testing and confirming them. The purpose of this study was to determine some selected LBA properties, whose characteristics are of interest for its use as an ingredient in foodstuffs. The discussion followed the results of Fourier‐Transform Infrared Spectroscopy (FTIR), X‐ray diffractometry (XRD), 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) radical, 2,2′‐azino‐bis(3‐ethylbenzothiazoline‐6‐sulphonic acid) (ABTS) radical, thermogravimetric/derivative thermogravimetry (TGA/DTG), minimal inhibitory concentration (MIC) by the diffusion disk test, scanning electron microscopy (SEM), and iron/calcium chelating methodologies. The XRD analysis revealed the presence of an amorphous halo and the absence of defined peaks, a fact possibly related to its high hygroscopicity. The FTIR showed characteristic bands of the LBA structure. Results from TGA/DG verified the LBA thermal degradation, which evidenced that LBA could participate in most food industry unit processes within the first mass loss event. Antioxidant capacity reached a maximum inhibition of 56% for LBA and the chelating capacity of the iron ion achieved 54% of chelated ions, while the calcium ions reached 15%. The results revealed high potential of LBA application for microbial inhibition, moisture retention, and texture maintenance throughout storage of food products. Practical Applications Despite the potential of application of the LBA, few quantitative results demonstrate its ability of action in food. Even without permission in most countries around the world, more research with LBA will encourage the investigation of its toxicology, expanding the areas of application. Its thermal degradation profile and elevated solubility demonstrated the potential of LBA as food ingredient, performing moreover as antioxidant, chelating agent, antimicrobial, and texturizer. The results open the possibilities for many applications in the field of food chemistry and food industry.
Article
The bioproduction of lactobionic acid and its salts can be performed by enzymatic complex glucose-fructose oxidoreductase (GFOR) and glucono-δ-lactonase (GL) of Zymomonas mobilis. Considering the applicability of these compounds in pharmaceutical area, the aim of this study was to assess the accelerated and long-term stability studies of sodium, potassium, calcium lactobionate, and lactobionic acid. Furthermore, stress tests were performed to evaluate the stability against pH, temperature and oxidation. The samples submitted to degradation tests were analyzed by high-performance liquid chromatography (HPLC) and high-resolution mass spectrometry analysis (HRMS-ESI-QTOF). Sodium, potassium, and calcium lactobionate were stable for six months of analyses considering the accelerated (40 °C and 75% RH) and long-term (30 °C and 75% RH) stability studies. The presence of lactobiono-δ-lactone and a significant increase in moisture were observed for both biosynthesized and commercially available lactobionic acid samples. Against the forced degradation tests, all the lactobionate salts and lactobionic acid showed to be stable upon alkaline and acid pH conditions, at 60 and 80 °C, and also against UV light exposition. Furthermore, the presence of lactobiono-δ-lactone form was observed in lactobionic acid samples. However, the degradation of both lactobionic acid and lactobionate salts was evident in the presence of hydrogen peroxide. This degradation kinetic profile suggests, that lactobionate salts follows a zero-order reaction model and lactobionic acid follows a second-order kinetic. The MS analysis of the main degradation product suggests a molecular formula C11H20O10 resulting from the oxidative decarboxylation. This report brings an amount of results as contribution to the scarce information regarding the chemical and physical-chemical stability of sodium, potassium, calcium lactobionate, and lactobionic acid. These data may be useful and serve as reference, in view of the multipurpose applications of the cited compounds.
Article
At pH 4.0, hydrous manganese oxide (HMO) oxidizes mandelic acid by two mole-equivalents of electrons, yielding phenylglyoxylic acid and benzaldehyde. These intermediates, in turn, are oxidized by two mole-equivalents of electrons to the same ultimate oxidation product, benzoic acid. The four compounds of the "reaction set" just described are conveniently monitored using capillary electrophoresis (CE) and HPLC. Extents of adsorption are negligible and their sum exhibits mass balance. Concentrations of phenylglyoxylic acid, benzaldehyde, and benzoic acid can therefore be used to calculate mole-equivalents delivered to HMO for comparison with experimentally-determined dissolved MnII concentrations. Semi-log plots (ln[substrate] versus time) and numerical analysis can also be used to explore rates of oxidation of the functional groups represented, i.e. an α-hydroxycarboxylic acid, an α-ketocarboxylic acid, and an aldehyde. Inserting a -CH2- group between the benzene ring and the functional groups just described yields a new reaction set comprised of phenyllactic acid, phenylpyruvic acid, and phenylacetaldehyde, plus the C-1 ultimate oxidation product, phenylacetic acid. At pH 4, mass balance for phenyllactic acid oxidation fell short by ~ 9 %. Phenyllactic acid was oxidized 2.7-times more slowly than mandelic acid, while phenylpyruvic acid was oxidized 12.7-times faster than phenylglyoxylic acid. Unlike benzaldehyde, oxidation rates for phenylacetaldehyde were too fast to measure. Under pH 4.0 conditions, this reaction set approach was used to explore the acceleratory effects of increases in HMO loading and inhibitory effects of 500 μM phosphate and pyrophosphate additions. Mandelic acid and phenyllactic acid were oxidized by HMO far more slowly at pH 7.0 than at pH 4.0. At pH 7.0, 2 mM MOPS and phosphate buffers did not yield appreciable dissolved MnII, despite oxidation of organic substrate. 2 mM Pyrophosphate, in contrast, solubilized HMO-bound MnII and MnIII.
Article
Objective The aim of the study was in vitro and in vivo characterization of cosmetic cream with 6% of standardized wild apple fruit extract, stabilized by conventional non‐ionic emulsifier‐CEW, in order to determine the influence of emulsifiers (conventional vs biodegradable) on the characteristics of creams and their effects on the skin. Methods Organoleptic and physico‐chemical (pH values and electrical conductivity) analysis was performed, determination of fruit acids‐FAs content (using HPLC analysis) and estimation of its antioxidant activity‐AA (using DPPH test) during 180 days. In vivo study included following examinations: screening of safety profile (after creams application under occlusion during 24h at human skin); skin moisturizing potential, transepidermal water loss‐TEWL, skin pH after 28 days of cream application and hypopigmentation efficacy 7 days of cream application at artificially induced skin hyperpigmentation. Results Investigated cosmetic cream‐CEW showed satisfactory organoleptic, physico‐chemical characteristics, stability, FAs content (0.13%) and AA (19.25±0.67%RSC) after preparation, which remained unchanged over the study period. In vivo investigation revealed absence of skin irritation after CEW's application under occlusion. An increase of skin moisturization (after 14 days ΔEC was 18.52 ± 11.51 and after 28 days of applications 16.52 ± 9.36) during 28 day‐study, with unchanged TEWL and skin pH values was shown. Decrease of melanin index was revealed, too (after 7 days ΔMI was ‐31.40±16.50). Conclusion Cosmetic cream stabilized by conventional emulsifier showed better antioxidant potential and weaker moisturizing and hypopigmentation effects related to the cream with same composition but stabilized by biodegradable emulsifiers. Based on all mentioned above, investigated cosmetic cream might be considered for potential use as modern, stable, safe and efficient cosmetic product in the prevention and/or treatment of oxidative stress‐related skin changes and/or damages, for moisturization of dry even irritated skin as well as for lightening of hyperpigmented skin. This article is protected by copyright. All rights reserved.
Article
Background Due to internal or external factors, the desquamation (turnover) rate of the stratum corneum slows down, resulting in skin problems. Therefore, adjusting the exfoliation rate through cosmetics is an important issue. Objective This report aimed to develop exfoliating agents with lesser adverse effects and higher efficiency through an ex vivo screening method and in vivo turnover rate analysis of human skin. Methods Various molecules were evaluated by the ex vivo porcine skin exfoliation method and screened for their potential as effective agents. To confirm the effect and mechanism of each agent found, the exfoliation efficiency was evaluated. Each agent was also applied to the actual human skin to determine its efficacy and side effects. Results Despite the pH 6, carnitine and serine, which have similar or better efficiency compared to PHA, were selected. Based on the results, it was confirmed that calcium. And it is nonirritating to the human skin and increases the turnover rate (~130%). Conclusion Amino acid‐based exfoliating agents, such as carnitine and serine, were identified and verified to enhance the rate of exfoliation of the stratum corneum. It is expected that the improvement of dullness, mild acne, fine wrinkles, and pores through skin exfoliation in the field of cosmetics can be achieved safely through these agents.
Article
Background Topical applications of alpha‐hydroxy acids and poly hydroxy acids in the form of peels gained popularity. To enhance the effect of these substances, aluminum oxide crystal microdermabrasion can be used in one procedure. Aims The assessment of skin hydration, elasticity, and TEWL after using lactobionic acid in the form of 20% peel and lactobionic acid in the form of 20% peel combined with aluminum oxide crystal microdermabrasion. Material and methods The study involved 20 Caucasian female subjects. Six treatments were performed at weekly intervals, using the Split face method—20% LA was used on the left side of the face and aluminum oxide crystal microdermabrasion followed by 20% LA application on the right side of the face. Results Corneometric measurement showed statistically significant differences between the hydration level for sessions 1 and 3 and 1 and 6. A higher hydration level was found on the side with the combined procedure. Tewametric measurement showed that the TEWL values were different for sessions 1 and 3 and 1 and 6—they decreased. There were no statistically significant differences between the two procedures. The cutometric measurement indicated statistically significant differences between skin elasticity for pairs in session 1 and 3 and 1 and 6. Conclusions The results of the study indicate that the combination of LA peel with microdermabrasion increases its moisturizing effect and improves skin elasticity. The use of both procedures also contributed to the decrease in TEWL; however, greater exfoliation of the epidermis in combined procedures resulted in slightly higher TEWL values.
Article
Background Recently more attention has been drawn to alpha hydroxy and polyhydroxy acids (AHA and PHA) due to their excellent moisturizing and antioxidant properties. These compounds are very beneficial in terms of both cosmetic and dermatological treatments. Objective The aim of this study was an assessment of moisturizing properties of lactobionic and lactic acids based on available literature. Methods Literature review using scientific databases: PubMed, Medline (EBSCO), Medline Complete, Karger, Springer/ICM, SpringerLink/online, Wiley Online Library. Results and Conclusions Through their construction, alpha AHA and PHA are able to bind large amounts of water and act as potent antioxidant agents through inhibition of matrix metalloproteinases and strong chelating properties. Another important characteristic is the maintenance of the epidermal barrier integrity during application of lactic acid (LAC) and lactobionic acid (LA) and thus the opportunity to use them on sensitive skin types including couperose skin.
Article
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Many studies have demonstrated beneficial health effects of topical antioxidant application; however, the underlying mechanisms are not well understood. To better understand the protective mechanism of oxogenous anti-oxidants, it is important to clarify the physiological distribution, activity and regulation of antioxidants. Also, the generation of ROS by the resident and transient microbial flora and their interaction with cutaneous antioxidants appears to be of relevance for the redox properties of skin. Our studies have demonstrated that alpha-tocopherol is, relative to the respective levels in the epidermis, the major antioxidant in the human SC, that alpha-tocopherol depletion is a very early and sensitive biomarker of environmentally induced oxidation and that a physiological mechanism exists to transport alpha-tocopherol to the skin surface via sebaceous gland secretion. Furthermore, there is conclusive evidence that the introduction of carbonyl groups into human SC keratins is inducible by oxidants and that the levels of protein oxidation increase towards outer SC layers. The demonstration of specific redox gradients within the human SC may contribute to a better understanding of the complex biochemical processes of keratinization and desquamation. Taken together, the presented data suggest that, under conditions of environmentally challenged skin or during prooxidative dermatological treatment, topical and/or systemic application of antioxidants could support physiological mechanisms to maintain or restore a healthy skin barrier. Growing experimental evidence should lead to the development of more powerful pharmaceutical and cosmetic strategies involving antioxidant formulations to prevent UV-induced carcinogenesis and photoaging as well as to modulate desquamatory skin disorders.
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Human studies have convincingly demonstrated pronounced photoprotective effects of 'natural' and synthetic antioxidants when applied topically before UVR exposure. Particularly with respect to UVB-induced skin damage such as erythema formation, the photoprotective effects of antioxidants are significant when applied in distinct mixtures in appropriate vehicles. Topical application of such combinations may result in a sustained antioxidant capacity of the skin, possibly due to antioxidant synergisms. And, since UVA-induced skin alterations are believed to be largely determined by oxidative processes [26], topical administration of antioxidants might be particularly promising [27, 28]. In fact, topical application of antioxidants or antioxidant mixtures resulted in a remarkable increase in the minimal dose to induce immediate pigment darkening after UVA exposure [18, 23] and diminished the severity of UVA-induced photodermatoses [22] in humans. In conclusion, regular application of skin care products containing antioxidants may be of the utmost benefit in efficiently preparing our skin against exogenous oxidative stressors occurring during daily life. Furthermore, sunscreening agents may also benefit from combination with antioxidants resulting in increased safety and efficacy of such photoprotective products [11, 29].
Article
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The primary function of the epidermis is to produce the protective, semi-permeable stratum corneum that permits terrestrial life. The barrier function of the stratum corneum is provided by patterned lipid lamellae localized to the extracellular spaces between corneocytes. Anucleate corneocytes contain keratin filaments bound to a peripheral cornified envelope composed of cross-linked proteins. The many layers of these specialized cells in the stratum corneum provide a tough and resilient framework for the intercellular lipid lamellae. The lamellae are derived from disk-like lipid membranes extruded from lamellar granules into the intercellular spaces of the upper granular layer. Lysosomal and other enzymes present in the extracellular compartment are responsible for the lipid remodeling required to generate the barrier lamellae as well as for the reactions that result in desquamation. Lamellar granules likely originate from the Golgi apparatus and are currently thought to be elements of the tubulo-vesicular trans-Golgi network. The regulation of barrier lipid synthesis has been studied in a variety of models, with induction of several enzymes demonstrated during fetal development and keratinocyte differentiation, but an understanding of this process at the molecular genetic level awaits further study. Certain genetic defects in lipid metabolism or in the protein components of the stratum corneum produce scaly or ichthyotic skin with abnormal barrier lipid structure and function. The inflammatory skin diseases psoriasis and atopic dermatitis also show decreased barrier function, but the underlying mechanisms remain under investigation. Topically applied "moisturizers" work by acting as humectants or by providing an artificial barrier to trans-epidermal water loss; current work has focused on developing a more physiologic mix of lipids for topical application to skin. Recent studies in genetically engineered mice have suggested an unexpected role for tight junctions in epidermal barrier function and further developments in this area are expected. Ultimately, more sophisticated understanding of epidermal barrier function will lead to more rational therapy of a host of skin conditions in which the barrier is impaired.
Chapter
In 1974 Van Scott and Yu first described the effects of alpha hydroxy acids (AHAs) on keratinization disorders. However, it was not until the 1990s that AHA products gained acceptance and popularity [1]. In this last decade, multiple reports showed the beneficial effects of AHAs in patients with xerosis and hyperkeratotic conditions [2-5]. As a result, AHA use by dermatologists and consumers increased dramatically. The main benefits of products containing these fruit-acid derivatives are the normalization of the keratinization process, replacement of water content, and stimulation of the epidermal cell renewal process [6].
Article
• Sixty patients with moderate to severe xerosis participated in a 21-day, randomized, double-blind, contralateral study for efficacy of a specially neutralized 12% lactate lotion compared with a 5% lactic acid lotion and a nonlactated emollient lotion. The severity of xerosis was evaluated on days 0, 7, 14, and 21 during treatment and on days 28 and 35 one and two weeks after treatment was discontinued. All three preparations significantly reduced the severity scores of xerosis. During the "regression" period after treatment was discontinued, patients receiving 12% lactate lotion, compared with those treated with nonlactated emollient lotion, had had significantly greater reductions in the severity scores of xerosis for the lateral calf area at days 28 and 35 and for total severity scores (combined mean differences for lateral, medial, and pretibial areas) at day 35. Compared with 5% lactic acid lotion, the 12% lactate lotion provided significantly greater reductions for total severity scores at days 28 and 35. (Arch Dermatol 1983;119:27-30)
Article
Background: Topical α-hydroxy acids (AHAs) have been shown to improve photoaging inhuman skin. Objective: We studied factor XIIIa transglutaminase expression in dermal dendrocytes (DDs) and mast cell degranulation after treatment of the skin with AHAs. Methods: Skin biopsy specimens obtained from patients after 4 to 8 months of treatment withlotions containing 25% AHAs were evaluated for factor XIIIa transglutaminase expression with immunoperoxidase and electron microscopy. Immunoperoxidase-stained sections were studied by means of semiquantitative methods and image analysis. Mast cell degranulation was studied by image analysis. Results: Increased factor XIIIa transglutaminase expression was seen after treatment withAHAs. All treated sites had increased scores compared with control sites by semiquantitative methods. Seventy-five percent of treated sites showed an increased mean area over control sites of factor XIIIa transglutaminase positivity with image analysis. These results correlated with an increased level of mast cell degranulation in treated sites and with activation of DDs as seen by electron microscopy. Conclusion: Treatment of the skin with AHAs leads to mast cell degranulation and increased expression of factor XIIIa transglutaminase by activated DDs. Mast cell degranulation may lead to activation of DDs and increased factor XIIIa transglutaminase expression, via the action of tumor necrosis factor-α. We speculate that clinical and histologic improvement in photoaged skin after treatment with AHAs may be somehow related to this process.
Article
Backgroound: alpha-Hydroxy acids (AHAs) have been reported to improve aging skin. The mechanisms of action of AHAs on epidermal and dermal compartments need clarification. Objective: Our purpose was to determine the effects of AHAs on photoaged human skin by clinical and microanalytic means. Methods: Patients applied a lotion containing 25% glycolic, lactic, or citric acid to one forearm and a placebo lotion to the opposite forearm for an average of 6 months. Thickness of forearm skin was measured throughout the study. Biopsy specimens from both forearms were processed for analysis at the end of the study. Results: Treatment with AHAs caused an approximate 25% increase in skin thickness. The epidermis was thicker and papillary dermal changes included increased thickness, increased acid mucopolysaccharides, improved quality of elastic fibers, and increased density of collagen. No inflammation was evident. Conclusion: Treatment with AHAs produced significant reversal of epidermal and dermal markers of photoaging.
Article
Background: Chronic solar irradiation results in both morphologic and functional changes in affected skin. alpha-hydroxy acids, such as glycolic acid, have been shown to improve photodamaged skin. Objective: To investigate alterations in collagen gene induction and epidermal and dermal hyaluronic acid production as a result of administered glycolic acid. Methods: In this study we compared collagen gene expression from skin biopsy specimens, and epidermal and dermal hyaluronic acid immunohistochemical staining between glycolic acid-treated and vehicle-treated skin. Forearm skin was treated with 20% glycolic acid lotion or a lotion vehicle control twice a day for 3 months. Results: Epidermal and dermal hyaluronic acid and collagen gene expression were all increased in glycolic acid-treated skin as compared to vehicle-treated controls. Conclusion: Our data suggest that epidermal and dermal remodeling of the extracellular matrix results from glycolic acid treatment. Longer treatment intervals may result in collagen deposition as suggested by the measured increase in mRNA.
Article
Alpha hydroxyacids (AHAs) are used to enhance stratum corneum desquamation and improve skin appearance. The purpose of this study was to evaluate whether some AHAs improve skin barrier function and prevent skin irritation. Eleven healthy subjects (aged 28 ± 6 years. mean ± SD) entered the study. Six test sites of 8×5 cm (four different AHAs, vehicle only (VE) and untreated control (UNT)) were selected and randomly rotated on the volar arm and forearm. The four different AHAs at 8% concentration in base cream were glycolic acid (GA), lactic acid, tartaric acid (TA) and gluconolactone (GLU). The products were applied twice a day for 4 weeks (2 mg/cm2). At week 4, a 5% sodium lauryl sulphate (SLS) challenge patch test was performed under occlusion for 6 h (HillTop chamber. 18 mm wide) on each site. Barrier function and skin irritation were evaluated by means of evaporimetry (Servomed EP-1) and chromametry (a* value, Minolta CR200) weekly, and at 0.24 and 48 h after SLS patch removal. No significant differences in transepidermal water loss (TEWL) and erythema were observed between the four AHAs at week 4. After SLS challenge. GLU and TA-treated sites resulted in significantly lower TEWL compared with VE, UNT (P<0.01) and GA (P<0.05) both at 24 and 48 h. Similarly, a* values were significantly reduced after irritation in GLU-and TA-treated sites. This study shows that AHAs can modulate stratum corneum barrier function and prevent skin irritation: the effect is not equal for all AHAs. being more marked for the molecules characterized by antioxidant properties.
Article
An assay of cultured skin fibroblasts identified several individuals with 3 beta-hydroxysteroid-sulphate sulphatase deficiency. All patients with this inborn error of metabolism had clinically apparent ichthyosis and a family history of this skin disorder compatible with X-linked inheritance. It is concluded that steroid-sulphatase deficiency is the bio-chemical basis of at least some cases of X-linked ichthyosis.
Article
Topical corticosteroids produce atrophic changes in skin, including thinning of the epidermis and decrease in dermal ground substance. We observed that 12% ammonium lactate produced an increase in the thickness of epidermis and increased amounts of dermal glycosaminoglycans. Our purpose was to determine whether 12% ammonium lactate could minimize cutaneous atrophy produced by a potent topical corticosteroid. Clobetasol propionate, 12% ammonium lactate, and both agents were repetitively applied under occlusive patches as well as in open patches on the forearms of human volunteers for 3 to 4 weeks. Biopsy specimens were analyzed for thickness of the epidermis and dermal glycosaminoglycans by image analysis. Twelve percent ammonium lactate produced a significant sparing of atrophy in both the epidermis and dermis without any influence on the bioavailability or antiinflammatory properties of the corticosteroid. Twelve percent ammonium lactate may be useful in mitigating the adverse effects of corticosteroid on skin.
Article
Alpha hydroxy acids and alpha keto acids applied topically in lower concentrations reduce the thickness of hyperkeratotic stratum corneum by reducing corneocyte cohesion at lower levels of the stratum corneum. This property permits efficient clinical control of dry skin, ichthyosis, follicular hyperkeratosis, and other conditions characterized by retention of stratum corneum. Applied topically in higher concentrations, these acids cause epidermolysis. This property provides a new alternative for treating seborrheic keratoses, keratoses commonly known as "age spots," actinic keratoses, and verrucae vulgares; all of which lesions involve distinct epidermal hyperplasia as well as retention of stratum corneum. Facial wrinkles can be modified with topical alpha hydroxy acids, applied in higher concentrations as office procedures, and concomitant daily home application of lower concentrations.
Article
We review the use of topical tretinoin (all-trans-retinoic acid) in the treatment of aging skin. We have found topical tretinoin capable of improving aged-appearing skin in both a double-blind, vehicle-controlled trial and our clinic patients. The most impressive improvement occurs after application of tretinoin 0.1% cream for 8 to 12 months. Side effects have been limited to a mild, transient, and clinically insignificant burning sensation in the eyes and mild irritation of tretinoin-exposed skin.
Article
Daily topical application of 0.05% tretinoin in a cream base was compared with its vehicle with regard to moderation of photoaging changes of the face and forearms. In comparison with the control tissue, tretinoin-treated tissue examined by light and electron microscopy showed the following effects: replacement of the atrophic epidermis by hyperplasia, elimination of dysplasia and atypia, eradication of microscopic actinic keratoses, uniform dispersion of melanin granules, new collagen formation in the papillary dermis, new vessel formation (angiogenesis), and exfoliation of retained horn in the follicles. Physiologic studies demonstrated: increased blood flow and dermal clearance, increased transepidermal water loss, and greater permeability and reactivity. It was concluded that topical tretinoin is capable of at least partly reversing the structural damages of excessive sunlight exposure and may be useful in decelerating the photoaging process.
Article
Topical preparations containing α-hydroxy acids and closely related compounds were found to exert profound effects on epidermal keratinization in ichthyosis. Therapeutically efficacious compounds include citric acid, ethyl pyruvate, glycolic acid, glucuronic acid, 3-hydroxybutyric acid, 2-hydroxyisobutyric acid, lactic acid, malic acid, methyl pyruvate, pyruvic acid, tartaric acid, and tartronic acid. These materials appear to influence the process of keratinization per se, but do not seem to be keratolytic.
Article
Hyperkeratinization is a primary or fundamental event in a majority of today's skin disorders. Hyperkeratinization is usually the result of decreased desquamation due to increased corneocyte cohesion. Strength of corneocyte cohesion is determined by strength of intercellular bonding. Intercellular bonding is weakened by water and diminished by retinoids and alpha hydroxy acids (AHAs). Conversely, bonding is strengthened or enhanced by dehydration, vitamin A deficiency, and some alpha acetoxy acids (AAAs). Agents that control or modify keratinization can be useful in treatment of many skin disorders.
Article
Sixty patients with moderate to severe xerosis participated in a 21-day, randomized, double-blind, contralateral study for efficacy of a specially neutralized 12% lactate lotion compared with a 5% lactic acid lotion and a nonlactated emollient lotion. The severity of xerosis was evaluated on days 0, 7, 14, and 21 during treatment and on days 28 and 35 one and two weeks after treatment was discontinued. All three preparations significantly reduced the severity scores of xerosis. During the "regression" period after treatment was discontinued, patients receiving 12% lactate lotion, compared with those treated with nonlactated emollient lotion, had had significantly greater reductions in the severity scores of xerosis for the lateral calf area at days 28 and 35 and for total severity scores (combined mean differences for lateral, medial, and pretibial areas) at day 35. Compared with 5% lactic acid lotion, the 12% lactate lotion provided significantly greater reductions for total severity scores at days 28 and 35.
Article
The Journal of Investigative Dermatology publishes basic and clinical research in cutaneous biology and skin disease.
Article
Topical retinoids have been employed in dermatology since the 1960s to treat a wide variety of cutaneous disorders. This review focuses on three areas in which retinoids have had their greatest impact: acne vulgaris, photoaging and cutaneous neoplasia. The pharmacology of the available topical retinoids, their mechanism of action and the history of their use in these disorders are discussed.
Article
Glycolic acid is an alpha hydroxyacid that is useful as a chemical peeling agent. To discuss the techniques using glycolic acid to remove actinic keratoses, fine wrinkles, lentigines, melasma, and seborrheic keratoses. Applied in a carefully timed manner, the depth of penetration can be titrated by the timed duration of application of acid on the skin. Chemical peels are left on the skin for 3 to 7 minutes for most patients. For ideal results, the chemical peel can be repeated 3 to 4 times. Glycolic acid can easily be used to peel skin of all skin types with minimal risk. We have found glycolic acid can be an ideal adjunct to other cosmetic modalities such as soft tissue augmentation.
Article
Although there is increasing interest in the use of glycolic acid in the treatment of photoaged skin, to our knowledge, no controlled study has been done to assess the efficacy or the mode of this agent. The purpose of this study was to determine whether 50% glycolic acid can improve photoaged skin and to study the histological basis for this improvement. Forty-one volunteers were recruited into this double-blind vehicle-controlled study. Glycolic acid (50%) or vehicle was applied topically for 5 minutes to one side of the face, forearms, and hands, once weekly for 4 weeks. Punch biopsies were taken at pretherapy and at 5 weeks for histologic study. Significant improvement noted included decrease in rough texture and fine wrinkling, fewer solar keratoses, and a slight lightening of solar lentigines. Histology showed thinning of the stratum corneum, granular layer enhancement, and epidermal thickening. Some specimens showed an increase in collagen thickness in the dermis. The results of this study demonstrate that the application of 50% glycolic acid peels improves mild photoaging of the skin.
Article
Topical alpha-hydroxy acids (AHAs) have been shown to improve photoaging in human skin. We studied factor XIIIa transglutaminase expression in dermal dendrocytes (DDs) and mast cell degranulation after treatment of the skin with AHAs. Skin biopsy specimens obtained from patients after 4 to 8 months of treatment with lotions containing 25% AHAs were evaluated for factor XIIIa transglutaminase expression with immunoperoxidase and electron microscopy. Immunoperoxidase-stained sections were studied by means of semiquantitative methods and image analysis. Mast cell degranulation was studied by image analysis. Increased factor XIIIa transglutaminase expression was seen after treatment with AHAs. All treated sites had increased scores compared with control sites by semiquantitative methods. Seventy-five percent of treated sites showed an increased mean area over control sites of factor XIIIa transglutaminase positivity with image analysis. These results correlated with an increased level of mast cell degranulation in treated sites and with activation of DDs as seen by electron microscopy. Treatment of the skin with AHAs leads to mast cell degranulation and increased expression of factor XIIIa transglutaminase by activated DDs. Mast cell degranulation may lead to activation of DDs and increased factor XIIIa transglutaminase expression, via the action of tumor necrosis factor-alpha. We speculate that clinical and histologic improvement in photoaged skin after treatment with AHAs may be somehow related to this process.
Article
alpha-Hydroxy acids (AHAs) have been reported to improve aging skin. The mechanisms of action of AHAs on epidermal and dermal compartments need clarification. Our purpose was to determine the effects of AHAs on photoaged human skin by clinical and microanalytic means. Patients applied a lotion containing 25% glycolic, lactic, or citric acid to one forearm and a placebo lotion to the opposite forearm for an average of 6 months. Thickness of forearm skin was measured throughout the study. Biopsy specimens from both forearms were processed for analysis at the end of the study. Treatment with AHAs caused an approximate 25% increase in skin thickness. The epidermis was thicker and papillary dermal changes included increased thickness, increased acid mucopolysaccharides, improved quality of elastic fibers, and increased density of collagen. No inflammation was evident. Treatment with AHAs produced significant reversal of epidermal and dermal markers of photoaging.
Article
The pathophysiology of acne vulgaris results from the interplay of follicular hyperkeratinization, the presence of Propionibacterium acnes bacteria in the follicular canal, and sebum production. Several anti-acne agents are currently available that affect one or more of these pathogenic factors and are effective against one or more acne lesion types. The only currently available agent that is directly effective against comedones is tretinoin. Agents effective against inflammatory lesions include tretinoin, benzoyl peroxide, and topical and systemic antibiotics. Agents effective against nodules and cysts include oral antibiotics and isotretinoin. However, the successful utilization of the available agents and techniques is highly dependent on an accurate and thorough assessment of each patient's needs and concerns, followed by the implementation of an individualized treatment program that has been clearly communicated to the patient. Such a program may employ several different anti-acne agents and adjunctive treatments such as comedo extraction or intralesional injection.
Article
Clinical studies of patients with melasma have shown that topical 20 percent azelaic acid is superior to 2 percent hydroquinone and as effective as 4 percent hydroquinone, without the latter's undesirable side effects. Tretinoin appears to enhance this effect of azelaic acid. Azelaic acid with tretinoin caused more skin lightening after three months than azelaic acid alone, and a higher proportion of excellent responders at the end of treatment. The effect of azelaic acid can be attributed to its ability to inhibit the energy production and/or DNA synthesis of hyperactive melanocytes, and partially to its antityrosinase activity. This may also account for the beneficial effect on postinflammatory hyperpigmentation. Destruction of malignant melanocytes by a combination of the same activities, enhanced by the greater permeability of tumoral cells to azelaic acid, may account for the clinical effects of azelaic acid observed in lentigo maligna and individual lesions of primary melanoma.
Article
Azelaic acid cream (20 percent) is a new topical treatment for acne with an additional therapeutic potential in rosacea and hyperpigmentation disorders. Azelaic acid (AzA; HOOC-(CH2)7-COOH) is a naturally occurring compound that interferes with acne pathogenesis by virtue of its antikeratinizing, antibacterial, and anti-inflammatory properties. Vehicle-controlled studies have verified that AzA exercises a significant and clinically relevant effect on both non-inflammatory and inflammatory acne lesions. Comparisons with clinically proven therapies have shown that 20 percent AzA cream is an effective monotherapy in mild to moderate forms of acne, with an overall efficacy comparable to that of tretinoin (0.05 percent), benzoyl peroxide (5 percent), and topical erythromycin (2 percent). In the treatment of moderate to severe acne, 20 percent AzA cream may be favorably combined with minocycline (90 percent good and excellent results), and may contribute towards reducing recurrences following discontinuation of systemic therapy (maintenance therapy with AzA cream). Particular advantages of AzA therapy include its favorable safety and side effect profile. It is non-teratogenic, is not associated with systemic adverse events or photodynamic reactions, exhibits excellent local tolerability, and does not induce resistance in Propionibacterium acnes.
Article
The development of new topical anti-acne therapies reflects the need for medications that address the requirements and concerns of an increasingly mature and demanding acne patient population. Some of the topical agents currently under investigation in the United States include several alpha-hydroxy acids (AHAs), the retinoids tazarotene and adapalene, and azelaic acid. All of these agents appear to exert their effect on acne through some effect on the process of keratinization and/or the thickness of the stratum corneum. Azelaic acid also has significant antimicrobial activity relevant to its efficacy in acne vulgaris. While azelaic acid has already been used successfully in many parts of the world for several years, the potential roles of the new retinoids in acne therapy are just beginning to be clarified. The properties of AHAs suggest that they may also be of value in the treatment of acne, but further systematic evaluation is needed.
Article
Recently, there has been an exponential increase in the use of alpha-hydroxy acids in dermatologic practice. Their inclusion in a myriad of cosmetic preparations underscores their popularity. Among the clinical effects of alpha-hydroxy acids are their ability to prevent the atropy resulting from potent topical corticosteroids, improve the appearance of photoaged skin, and correct disorders of keratinization. Despite this range of desirable effects, very little is known about the specific changes produced by various alpha-hydroxy acid preparations in the epidermis and dermal extracellular matrix. Previous work by others has demonstrated the ability of another alpha-hydroxy acid to increase viable epidermal thickness, and dermal glycosaminoglycans. In this study, we examined the effect of 20% citric acid lotion, as compared with vehicle alone, on skin thickness, viable epidermal thickness, and dermal glycosaminoglycan content. Biopsy samples were harvested after 3 months of treatment. Image analysis of biopsy sections revealed increases in viable epidermal thickness and dermal glycosaminoglycans in treated skin. Topical citric acid produces changes similar to those observed in response to glycolic acid, ammonium lactate, and retinoic acid including increases in epidermal and dermal glycosaminoglycans and viable epidermal thickness. Further studies of citric acid and other alpha-hydroxy acids are warranted to clarify their clinical effects and mechanisms of action.
Article
Alpha hydroxyacids (AHAs) are used to enhance stratum corneum desquamation and improve skin appearance. The purpose of this study was to evaluate whether some AHAs improve skin barrier function and prevent skin irritation. Eleven healthy subjects (aged 28 +/- 6 years, mean +/- SD) entered the study. Six test sites of 8 x 5 cm (four different AHAs, vehicle only (VE) and untreated control (UNT) were selected and randomly rotated on the volar arm and forearm. The four different AHAs at 8% concentration in base cream were glycolic acid (GA), lactic acid, tartaric acid (TA) and gluconolactone (GLU). The products were applied twice a day for 4 weeks (2 mg/cm2). At week 4, a 5% sodium lauryl sulphate (SLS) challenge patch test was performed under occlusion for 6 h (HillTop chamber, 18 mm wide) on each site. Barrier function and skin irritation were evaluated by means of evaporimetry (Servomed EP-1) and chromametry (a* value, Minolta CR200) weekly, and at 0, 24 and 48 h after SLS patch removal. No significant differences in transepidermal water loss (TEWL) and erythema were observed between the four AHAs at week 4. After SLS challenge, GLU- and TA-treated sites resulted in significantly lower TEWL compared with VE, UNT (P < 0.01) and GA (P < 0.05) both at 24 and 48 h. Similarly, a* values were significantly reduced after irritation in GLU- and TA-treated sites. This study shows that AHAs can modulate stratum corneum barrier function and prevent skin irritation; the effect is not equal for all AHAs, being more marked for the molecules characterized by antioxidant properties.
Article
Vitamins have been increasingly used as prophylactic and therapeutic agents in the management of skin disorders. The current literature is replete with studies that promote the potential benefits of these compounds and attempt to elucidate their mechanisms of action. We review the literature and discuss the roles, safety, and efficacy of vitamins A, C, and E and related compounds in cutaneous health and disease.
Article
We compared the activity and tolerance profile of a 0.05% retinaldehyde cream with a 0.05% retinoic acid cream and the retinaldehyde vehicle in patients with photodamaged skin of the face. A silicone replica of the left crow's feet area was taken at baseline and at weeks 18 and 44. Skin replicas were then analyzed by means of an optical profilometry technique. Standard wrinkle and roughness features were then calculated and statistically analyzed. The tolerance profile of the test products was also clinically evaluated during the entire study. A total of 125 patients (40 in the retinoic acid group, 40 in the retinaldehyde group, and 45 in the vehicle group) were studied. At week 18, a significant reduction of the wrinkle and roughness features was observed with both retinaldehyde and retinoic acid. At week 44, a less pronounced reduction was demonstrated in both active groups. No statistically significant changes were observed with the retinaldehyde vehicle at any assessment point. A total of 135 patients constituted the safety population. Retinaldehyde was well tolerated during the entire study. In contrast, retinoic acid caused more local irritation, and affected compliance of the patients. Retinaldehyde was efficacious and well tolerated in patients with photodamage.
Article
Glycolic acid chemical peels have been widely accepted as a useful modality in many cutaneous conditions characterized by abnormalities of keratinization. The aim of this study is to evaluate the use of glycolic peels in the main clinical forms of acne. Between January 1995 and December 1996, 80 women, aged 13-40 years, were visited for acne and selected for the study at the Cagliari University Dermatology Department (Italy). The type and severity of acne in each patient was assessed following the Leeds technique. The chemical peels were performed with a 70% glycolic acid solution, for times that varied in a range between 2 and 8 minutes. The number and frequency of the applications depended on the intensity of the clinical response. The main clinical forms were comedonic acne in 32 cases, papulo-pustular acne in 40 cases and nodule-cystic acne in the remaining eight cases. The most rapid improvement was observed in comedonic acne. In the papulo-pustular forms an average of six applications was necessary. Although nodular-cystic forms required eight to ten applications, a significant improvement of the coexisting post-acne superficial scarring was noted. The procedure was well tolerated and patient compliance was excellent. Glycolic acid chemical peels are an effective treatment for all types of acne, inducing rapid improvement and restoration to normal looking skin.
Article
Unlabelled: New methods to protect skin from photodamage from sun exposure are necessary if we are to conquer skin cancer and photoaging. Sunscreens are useful, but their protection is not ideal because of inadequate use, incomplete spectral protection, and toxicity. Skin naturally uses antioxidants (AOs) to protect itself from photodamage. This scientific review summarizes what is known about how photodamage occurs; why sunscreens--the current gold standard of photoprotection--are inadequate; and how topical AOs help protect against skin cancer and photoaging changes. This review is intended to be a reference source, including pertinent comprehensive reviews whenever available. Although not all AOs are included, an attempt has been made to select those AOs for which sufficient information is available to document their potential topical uses and benefits. Reviewed are the following physiologic and plant AOs: vitamin C, vitamin E, selenium, zinc, silymarin, soy isoflavones, and tea polyphenols. Their topical use may favorably supplement sunscreen protection and provide additional anticarcinogenic protection. (J Am Acad Dermatol 2003;48:1-19.) Learning objective: At the completion of this learning activity, participants should have an understanding of current information about how the sun damages skin to produce skin cancer and photoaging changes, how the skin naturally protects itself from the sun, the shortcomings of sunscreens, and the added advantages of topical AOs for photoprotection.
Article
Most alpha-hydroxyacids and polyhydroxy acids are physiologic, natural, and nontoxic substances. All members of the group promote normal keratinization and desquamation. Those with multiple hydroxyl groups are moisturizing antioxidants, and are especially gentle for sensitive skin. Alpha-hydroxyacids and polyhydroxy acids can increase biosynthesis of glycosaminoglycans and collagen fibers, and cause substantial skin plumping and increased dermal thickness. Formulation of alpha-hydroxyacids and polyhydroxy acids in combination with pharmaceutical agents can enhance efficacy and diminish or eliminate side effects and drug resistance. N-acetylamino sugars and N-acetylamino acids are two other categories of physiologic substances that can: 1) increase skin thickness; 2) improve wrinkles and photoaged skin; and 3) eradicate itch in senile and eczematous dermatitis.
Lactobionic acid and Gluconolactone. PHAs for photoaged skin
  • Green
  • Edison Bl Ba
  • Wildnauer
11 Green BA, Edison BL, Wildnauer RH et al. Lactobionic acid and Gluconolactone. PHAs for photoaged skin. Cosmet Dermatol 2001; 9: 24 – 8.
Connective tissue alterations in photodamaged skin and the effects of alpha hydroxy acids
  • Bernstein EF
45 Bernstein EF, Uitto J. Connective tissue alterations in photodamaged skin and the effects of alpha hydroxy acids. J Ger Dermatol 1995; Suppl. A: 7A–18A.
Polyhydroxy acids (PHAs) Clinical uses for the next generation of hydroxy acids
  • Ef Bernstein
  • Green
  • Ba
  • Edison
10 Bernstein EF, Green BA, Edison B et al. Polyhydroxy acids (PHAs). Clinical uses for the next generation of hydroxy acids. Skin & Ageing Suppl 2001; 9: 4–11.
Hydroxyacids and their topical use in the elderly Skin Diseases in the Elderly Alpha-hydroxy acids. Science and therapeutic use
  • Van Ej Scott
  • Yu Rj
  • Nall
  • Cauwenbergh
20 Van Scott EJ, Yu RJ. Hydroxyacids and their topical use in the elderly. In: L Nall, G Cauwenbergh, P Jacobs, eds Skin Diseases in the Elderly. New York: Marcel Dekker. in press. 21 Yu RJ, Van Scott EJ. Alpha-hydroxy acids. Science and therapeutic use. Cosmet Dermatol 1994; 10 (Suppl.): 12– 20.
Bioavailable alpha hydroxy acid in topical formulations
  • Van Scott Ej
  • Moy
  • bullet Luftman
  • Van
  • Scott
22 Yu RJ, Van Scott EJ. Bioavailable alpha hydroxy acid in topical formulations. In: R Moy, D Luftman, L Kakita, eds α-Hydroxyacids & carboxylic acids @BULLET R J Yu & E J Van Scott © 2004 Blackwell Publishing Ltd @BULLET Journal of Cosmetic Dermatology, 3, 76–87 87
Salicylic acid. Not a beta‐hydroxy acid
  • Yu RJ
18 Yu RJ, Van Scott EJ. Salicylic acid. Not a beta-hydroxy acid. Cosmet Dermatol 1997; 10: 27.
Substances that modify the stratum corneum by modulating its formation
  • Van Ej Scott
  • Yu
2 Van Scott EJ, Yu RJ. Substances that modify the stratum corneum by modulating its formation. In: P Frost, SN Horwitz, eds Principles of Cosmetics for the Dermatologist. C. V. Mosby: St. Louis, 1982: pp. 70 – 4.
A discussion of control‐release formulations of AHAs
  • Yu RJ