Active ingredients, mechanisms of action and efficacy tests of antipollution cosmetic and personal care products

The Potential Application of Nanocarriers in Delivering Topical Antioxidants

The imbalance in the production of reactive oxygen species (ROS) with endogenous antioxidant capacity leads to oxidative stress, which drives many disorders, especially in the skin. In such conditions, supplementing exogenous antioxidants may help the body prevent the negative effect of ROS. However, the skin, as the outermost barrier of the body, provides a perfect barricade, making the antioxidant delivery complicated. Several strategies have been developed to enhance the penetration of antioxidants through the skin, one of which is nanotechnology. This review focuses on utilizing several nanocarrier systems, including nanoemulsions, liposomes, solid lipid nanoparticles (SLNs), nanostructured lipid carriers (NLCs), and polymeric nanoparticles, for transporting antioxidants into the skin. We also reveal ROS formation in the skin and the role of antioxidant therapy, as well as the natural sources of antioxidants. Furthermore, we discuss the clinical application of topical antioxidant therapy concomitantly with the current status of using nanotechnology to deliver topical antioxidants. This review will accelerate the advancement of topical antioxidant therapy.

Effects of Investigational Moisturizers on the Skin Barrier and Microbiome following Exposure to Environmental Aggressors: A Randomized Clinical Trial and Ex Vivo Analysis

The skin microbiota barrier participates in skin barrier function in addition to the physical, chemical, and immunological protective barriers, and is affected by environmental aggressors and skincare regimens. To better understand the exact effects of real-life environmental conditions on the skin and determine the protective methods, this study investigates the effects of three topical cosmetic moisturizers (water gel moisturizers with/without yeast extract (Moisturizers K and C) and a thick-emulsion cream moisturizer (Moisturizer L)) on clinical and skin microbiome endpoints in the presence of environmental aggressors during an 8-week, randomized controlled, triple-blind clinical trial with 110 participants, and molecular- as well as biomarker-level endpoints on ex vivo skin explants after exposure to simulate urban environmental conditions. The results show that all moisturizers are well-tolerated and improve skin barrier function and surface moisture content from the baseline, and the improvement is maintained at the last analysis point (3 days after trial completion). Compared with the untreated control areas (samples taken from the upper chest), treatment with Moisturizer K prevented a reduction in bacterial and fungal richness, and increased the change ratio of the relative abundance of commensal bacteria, such as Staphylococcus epidermidis and Ralstonia, at the treated sites (samples taken from the forehead). Moreover, Moisturizer K-treated ex vivo skin explants had higher levels of caspase 14 (a marker of skin barrier function), collagen I, and elastin (structure components), and lower levels of aryl hydrocarbon receptor (AHR; activated by air pollutants) and interleukin-6 (IL-6) than those in explants treated with other moisturizers and in the untreated areas of the skin. These results suggest that a skin postbiotic moisturizer with yeast extract supports the regulation of the skin's microbiome balance and may provide a holistic barrier (involving skin microbiome, physical, chemical, and immune barriers) to protect the skin against environmental aggressors.

Clinical Evaluation of Indian Sandalwood Oil and Its Protective Effect on the Skin against the Detrimental Effect of Exposome

The skin is constantly subject to external stressors (the exposome), including particulate matter and blue light. These can penetrate the deeper layers of the skin, inducing the release of free radicals and triggering an inflammatory cascade of events contributing to cutaneous aging and exacerbating inflammatory skin conditions. This study demonstrates the clinical efficacy of Indian sandalwood oil of varying concentrations against oxidative stress induced by urban dust and blue light. Twenty-two healthy human subjects entered and completed the study of 11 days. Test products containing 0.1%, 1% and 10% of sandalwood oil, as well as a placebo and a comparator control (α-tocopherol), were applied on the different investigational zones of the upper back of each subject. Exposure ensued on day 7, using a controlled pollution exposure system (CPES) and blue light at a wavelength of 412 nm. Sebum was sampled on each investigational zone following the last exposure. The level of squalene monohydroperoxide (SQOOH) was the primary endpoint. A dose-dependent decrease in SQOOH on the zones treated with 10%, 1% and 0.1% of the sandalwood oil formulation compared to the untreated zones was observed. The zone treated with the 10% sandalwood-containing formula demonstrated the highest protective efficacy with the lowest amount of SQOOH. Increasing the concentration of the sandalwood oil increased its protective antioxidant activity. The results collected from this intraindividual comparative is the first clinical trial to suggest that sandalwood oil at a concentration between 1% and 10% protects the skin against the oxidative stress induced by urban dust and blue light exposure.

Cliona varians-Derived Actinomycetes as Bioresources of Photoprotection-Related Bioactive End-Products

Sunscreen and sunblock are crucial skincare products to prevent photoaging and photocarcinogenesis through the addition of chemical filters to absorb or block ultraviolet (UV) radiation. However, several sunscreen and sunblock ingredients, mostly UV filters, have been associated with human and environmental safety concerns. Therefore, the exploration and discovery of promising novel sources of efficient and safer compounds with photoprotection-related activities are currently required. Marine invertebrates, particularly their associated microbiota, are promising providers of specialized metabolites with valuable biotechnological applications. Nevertheless, despite Actinobacteria members being a well-known source of bioactive metabolites, their photoprotective potential has been poorly explored so far. Hence, a set of methanolic extracts obtained from Cliona varians-derived actinomycetes was screened regarding their antioxidant and UV-absorbing capacities (i.e., photoprotection-related activities). The active extract-producing strains were identified and classified within genera Streptomyces, Micrococcus, Gordonia, and Promicromonospora. This is the first report of the isolation of these microorganisms from C. varians (an ecologically important Caribbean coral reef-boring sponge). The in vitro cytotoxicity on dermal fibroblasts of oxybenzone and the selected active extracts revealed that oxybenzone exerted a cytotoxic effect, whereas no cytotoxic effect of test extracts was observed. Accordingly, the most active (SPFi > 5, radical scavenging > 50%) and nontoxic (cell viability > 75%) extracts were obtained from Streptomyces strains. Finally, LC-MS-based characterization suggested a broad chemical space within the test strains and agreed with the reported streptomycetes' chemodiversity. The respective metabolite profiling exposed a strain-specific metabolite occurrence, leading to the recognition of potential hits. These findings suggest that marine Streptomyces produce photoprotectants ought to be further explored in skincare applications.

Novel Spray Dried Algae-Rosemary Particles Attenuate Pollution-Induced Skin Damage

The present study investigated the effect of spray-dried algae-rosemary particles against pollution-induced damage using ex-vivo human biopsies exposed to diesel engine exhaust (DEE). For this, the complexation of hydroalcoholic rosemary extract with Chlorella (RCH) and Spirulina (RSP) protein powders was conducted. The process efficiency and concentration of rosmarinic acid (RA), carnosic acid (CA), and carnosol (CR) phenolic compounds of both products were compared. The RSP spray-dried production was more efficient, and RSP particles presented higher CR and CA and similar RA concentrations. Therefore, spray-dried RSP particles were prioritized for the preparation of a gel formulation that was investigated for its ability to mitigate pollution-induced skin oxinflammatory responses. Taken altogether, our ex-vivo data clearly demonstrated the ability of RSP gel to prevent an oxinflammatory phenomenon in cutaneous tissue by decreasing the levels of 4-hydroxynonenal protein adducts (4HNE-PA) and active matrix metalloproteinase-9 (MMP-9) as well as by limiting the loss of filaggrin induced by DEE exposure. Our results suggest that the topical application of spirulina-rosemary gel is a good approach to prevent pollution-induced skin aging/damage.

Antioxidant and Anti-Aging Potential of Indian Sandalwood Oil against Environmental Stressors In Vitro and Ex Vivo

Distilled from the heartwood of Santalum album, Indian sandalwood oil is an essential oil that historically has been used as a natural active ingredient in cosmetics to condition and brighten the skin. It has been documented to exhibit antioxidant, anti-inflammatory, and anti-proliferative activities. Here, we investigated the protective and anti-aging effects of Indian sandalwood oil in scavenging reactive oxygen species (ROS) in HaCaT cells and in human skin explants after exposure to oxidative stress. Using a probe DCFH-DA, the antioxidant capacity of Indian sandalwood oil was monitored following exposure to blue light at 412 nm and 450 nm or cigarette smoke. The anti-aging effect of sandalwood oil was also explored in human skin explants via the assessment of collagenase level (MMP-1). We reported that Indian sandalwood oil possessed antioxidant potential that can scavenge the ROS generated by a free radical generating compound (AAPH). Subsequent exposure to environmental stressors revealed that Indian sandalwood oil possessed superior antioxidant activity in comparison to vitamin E (alpha tocopherol). Using human skin explants, this study demonstrated that Indian sandalwood oil can also inhibit the pollutant-induced level of MMP-1. The findings indicated that Indian sandalwood oil can potentially serve as a protective and anti-aging active ingredient in cosmetics and dermatology against environmental stressors.

(Bio)Technological aspects of microalgae pigments for cosmetics

Photosynthetic microorganisms convert carbon dioxide and solar radiation into interesting bioactive compounds not yet entirely explored. Several species of microalgae are known to be rich in colored high-valuable components that, although remarkable, are poorly explored as natural sources of pigments for cosmetics. Pigments associated to photosynthetic activity include chlorophyll, β-carotene, astaxanthin, xanthophylls, and phycobiliproteins, many of which have shown high potential as cosmetic actives due to their antioxidant, immune-enhancing, and anti-inflammatory properties. In the last decade, concern with a young and beautiful appearance has emerged, encouraging many consumers to use anti-aging cosmetics daily. As a result, the cosmetic market has been growing and evolving rapidly to meet consumer expectations. However, due to regular use and the sensitive nature of facial skin, local adverse reactions may often occur, such as irritation, sensitization, or photoreactions, and safety evaluation is mandatory prior to marketing. It is, therefore, understandable that new actives from natural sources, such as microalgae, are perceived as attractive alternatives for consumers who seek ingredients without allergenic potential. Thus, the cosmetic industry has recently started to explore the inclusion of compounds extracted from microalgae and cyanobacteria in innovative formulations. Herein, we revised nontraditional microalgae species for pigment production with cosmetic applications, indicating those that could also be considered potential ingredients for innovative cosmetics. KEY POINTS: • Extraction methods for pigments from photosynthetic microorganisms were compiled. • Innovative cosmeceuticals could be developed with natural pigments. • Safety features of such natural pigments were also described.

Contribution of Topical Antioxidants to Maintain Healthy Skin—A Review

The skin is constantly exposed to various environmental stresses, in particular to the damage caused by pollution and ultraviolet radiation (UV), and as a consequence, the horny extract can be negatively impacted by the harmful influence of some of its surface components. The mechanisms involved in the degradation processes promoted by UV radiation are driven by the direct absorption of radiation via cellular chromophores, the formation of excited states and the consequent chemical reactions, or even by the photosensitization mechanisms, in which UV light is absorbed by the sensitizers that are excited and their reactions promote the formation of reactive oxygen species (ROS). The mechanisms of polluting agents are not yet fully understood, however, they indicate that one of the main mechanisms involved is oxidative stress by lipid peroxidation, with the ability to promote damage to the composition of sebum, the quality of the stratum corneum and also, promote aging skin. Recent studies demonstrate the potential of antioxidant agents, with an emphasis on products of natural origin, which try to promote the maintenance of the physiological balance of the skin.