Search Results (85)

This study presents the first comprehensive theoretical investigation of the antioxidant mechanisms of trans-isoferulic acid against hydroperoxyl (HOO^•) radicals in aqueous solution, using the DFT/M062X/6-311+G(d,p)/PCM method. Thermodynamic and kinetic parameters, including reaction energy barriers and bimolecular rate constants, were determined for the three major pathways: hydrogen transfer (HT), radical adduct formation (RAF), and single electron transfer (SET). The results indicate that, at physiological pH, the RAF mechanism is both more exergonic and approximately eight-times faster than HT. At a higher pH, where the phenolate anion dominates, antioxidant activity is enhanced by an additional fast, diffusion-limited SET pathway. Isoferulic acid was also found to effectively chelate Fe²⁺ ions at pH 7.4 and above, forming stable complexes that could inhibit Fenton-type hydroxyl radical generation. Moreover, its strong UV absorption suggests a role in limiting photo-induced free radical formation. These findings not only clarify the antioxidant behavior of isoferulic acid but also provide novel theoretical insights applicable to related phenolic compounds. The compound’s multi-target antioxidant profile highlights its potential as a photoprotective agent in sunscreen formulations. Full article

The depletion of the ozone layer and climate change have increased exposure to ultraviolet (UV) radiation, driving the search for natural photoprotective agents. Marine macroalgae, particularly Gracilaria sp. (Rhodophyta) and Sargassum polyceratium (Ochrophyta), are rich in UV-absorbing bioactives, such as mycosporine-like amino acids (MAAs) and fucoxanthin, offering natural alternatives to synthetic sunscreens. This study aimed to develop and optimize a nanoemulsion incorporating both algal extracts, with MAAs and fucoxanthin strategically distributed in the aqueous and oil phases, respectively, to enhance synergistic broad-spectrum UV protection. MAAs were quantified in Gracilaria sp. using UHPLC-DAD, revealing 8.03 mg/g dry weight, primarily composed of shinorine and porphyra-334. Fucoxanthin was identified in S. polyceratium at 0.98 mg/g dry weight. A Box–Behnken design (BBD) was employed to optimize the nanoemulsion, targeting minimal droplet size and optimal ζ potential. The resulting formulation achieved a droplet size less than 100 nm and a ζ potential less than −25.0 mV. In vitro spectrophotometric analysis demonstrated significant photoprotective potential. The nanoemulsion containing only 375 ppm of algal extracts exhibited a UVA ratio of 1.25 and a critical wavelength of 379 nm, meeting the criteria for broad-spectrum protection and outperforming the commercial natural filter Helioguard^®365. These results confirm the efficacy of combining red and brown algae extracts in a nanoemulsion platform to deliver sustainable, low-dose photoprotection. This work presents, for the first time, the incorporation of red and brown algae extracts into a single nanoemulsion system, representing a novel strategy to maximize the combined photoprotective potential of MAAs and fucoxanthin. Ultimately, this investigation contributes to the growing field of marine-derived sunscreens and supports the advancement of “blue beauty” innovations aligned with eco-conscious formulation principles. Full article

Comparing electroanalysis and chromatography, this study highlights that electroanalysis, specifically using a glassy carbon sensor (GCS), is the most appropriate choice for quantifying recalcitrant organic compounds. Octocrylene (OC), an organic compound commonly found in sunscreens, is of particular concern in swimming pool water monitoring, as its presence above legal limits poses health risks. OC quantification was performed using both high performance liquid chromatography (HPLC) and electroanalysis in sunscreen formulations and water matrices. The limits of detection (LODs) and quantification (LOQ) for OC were approximately 0.11 ± 0.01 mg L⁻¹ and 0.86 ± 0.04 mg L⁻¹ by electroanalysis, and 0.35 ± 0.02 mg L⁻¹ and 2.86 ± 0.12 mg L⁻¹ by HPLC. Electroanalysis successfully quantified OC in real sunscreen samples, and the results were comparable to those obtained by HPLC. The matrices tested—swimming pool water and distilled water (containing 0.002 M Cl⁻) contaminated with 0.4 ± 0.2 g L⁻¹ of sunscreen (based on a maximum concentration in sunscreen and cosmetic formulations of 10%)—showed OC concentrations below 10% in the formulation, with no significant differences observed between the two techniques. GCS was further utilized to monitor OC degradation via anodic oxidation at current densities of 5 and 10 mA cm⁻², using a boron-doped diamond (BDD) anode. The combined approach demonstrated high efficacy in both detecting and eliminating OC from various water matrices, making it a reliable and efficient alternative for environmental and water quality monitoring. Full article

Green tea catechins (GTCs) are a group of bioactive polyphenolic compounds found in fresh tea leaves (Camellia sinensis (L.) O. Kuntze). They have garnered significant attention due to their diverse health benefits and potential therapeutic applications, including as antioxidant and sunscreen agents. Human skin serves as the primary barrier against various external aggressors, including pathogens, pollutants, and harmful ultraviolet radiation (UVR). Skin aging is a complex biological process influenced by intrinsic factors such as genetics and hormonal changes, as well as extrinsic factors like environmental stressors, among which UVR plays a pivotal role in accelerating skin aging and contributing to various dermatological conditions. Research has demonstrated that GTCs possess potent antioxidant properties that help neutralize free radicals generated by oxidative stress. This action not only mitigates cellular damage but also supports the repair mechanisms inherent in human skin. Furthermore, GTCs exhibit anti-carcinogenic effects by inhibiting pathways involved in tumor promotion and progression. GTCs have been shown to exert anti-inflammatory effects through modulation of inflammatory signaling pathways. Chronic inflammation is known to contribute significantly to both premature aging and various dermatological diseases such as psoriasis or eczema. By regulating these pathways effectively, GTCs may alleviate symptoms associated with inflammatory conditions. GTCs can enhance wound healing processes by stimulating angiogenesis. They also facilitate DNA repair mechanisms within dermal fibroblasts exposed to damaging agents. The photoprotective properties attributed to GTCs further underscore their relevance in skincare formulations aimed at preventing sun-induced damage. Their ability to screen UV light helps shield underlying tissues from harmful rays. This review paper aims to comprehensively examine the beneficial effects of GTCs on skin health through an analysis encompassing in vivo and in vitro studies alongside insights into molecular mechanisms underpinning these effects. Such knowledge could pave the way for the development of innovative strategies focused on harnessing natural compounds like GTCs for improved skincare solutions tailored to combat environmental stresses faced by the human epidermis. Full article

The aim of this research was to design and synthesize new lipid conjugates of 7-DHC that could serve as a new storage form of esterified provitamin D₃, increasing the reservoir of this biomolecule in the epidermis and enabling controlled production of vitamin D₃ even during periods of sunlight deficiency. Acylglycerol and glycerophospholipid containing succinate-linked provitamin D₃ at the sn-2 position of the glycerol backbone were synthesized from dihydroxyacetone (DHA) and sn-glycerophosphocholine (GPC), respectively. The three-step synthesis of 1,3-dipalmitoyl-2-(7-dehydrocholesterylsuccinoyl)glycerol involved the esterification of DHA with palmitic acid, reduction of the carbonyl group, and conjugation of the resulting 1,3-dipalmitoylglycerol with 7-dehydrocholesterol hemisuccinate (7-DHC HS). The use of NaBH₃CN as a reducing agent was crucial to avoid acyl migration and achieve the final product with 100% regioisomeric purity. For the preparation of 1-palmitoyl-2-(7-dehydrocholesterylsuccinoyl)-sn-glycero-3-phosphocholine, a two-step process was applied, involving the esterification of GPC at the sn-1 position with palmitic acid, followed by the conjugation of 1-palmitoyl-sn-glycero-3-phosphocholine with 7-DHC HS. Alongside the main product, a small amount of its regioisomer with provitamin D₃ linked at the sn-1 position and palmitic acid at the sn-2 position was detected, indicating acyl migration from the sn-1 to the sn-2 position in the intermediate 1-palmitoyl-sn-glycerophosphocholine. The synthesized novel lipids were fully characterized using spectroscopic methods. They can find applications as novel lipid-based prodrugs as additives to sunscreen creams. Full article

Film-forming agents are key ingredients in achieving long-lasting and effective sun protection by sunscreens. However, studies on the synergistic effects of film-forming agents with different properties as well as the interaction between film-forming agents and powders are scarce, restricting the development of sunscreens with strong ultraviolet (UV)-shielding effects. Herein, we innovatively adopt polysiloxane-15 as the soft film, trimethylsiloxysilicate as the hard film, and vinyl dimethicone/methicone silsesquioxane crosspolymer as the functional powder to construct a co-assembled sunscreen film, and we investigate the property-enhancing effects of the sunscreen film as well as the interaction between the silicone polymer-based film-forming agents and functional powder therein. The results show that structural similarity is essential to generating film-forming agent–powder interactions, which primarily enhance the Si−O bond binding energy, thereby enhancing the lasting protection effect of sunscreens. In addition, the inter-component interaction of the co-assembled sunscreen film inhibits the agglomeration of sunscreen paste to facilitate the formation of a homogeneous film, endowing the sunscreen with excellent UV protection abilities, with the sun protection factor (SPF) and protection factor of UVA (PFA) values increased by 61.58 and 43.84%, respectively. This work offers novel insights into the optimization of film-forming agent properties and the development of durable and efficient sunscreens. Full article

Coffea arabica, Centella asiatica, and Curcuma longa extracts have demonstrated significant antioxidant and anti-aging activities. However, research on combining these three extracts in specific proportions to enhance their antioxidant and anti-hyaluronidase effects remains limited. Therefore, this study aimed to determine the optimal proportions of C. arabica, C. asiatica, and C. longa extracts to maximize their combined antioxidant and anti-hyaluronidase activities. A two-level full factorial design was used to identify the optimal concentration ratios of the mixed extracts. The results indicated that all extracts influenced antioxidant activity, with the optimal proportions of C. arabica, C. asiatica, and C. longa extracts being 0.5:6:2 mg/mL, respectively. In addition, all factors affected hyaluronidase enzyme inhibition, with the optimal proportions for C. arabica, C. asiatica, and C. longa extracts being 10:10:5 mg/mL to achieve the best inhibition. In a photostability study on individual extracts, mixed extracts, and mixed extracts combined with sodium metabisulfite and bis-ethylhexyloxyphenol methoxyphenyl triazine, it was observed that preparing the mixed extracts and adding an antioxidant and a sunscreen agent helped reduce the photodegradation of phenolic compounds in the mixed extracts. Consequently, the stabilized mixed extracts could serve as raw materials in cosmetic products. Full article

Chitosan (Ch), a natural polysaccharide, is known for its biocompatibility, biodegradability, and various beneficial properties, including antioxidant and antibacterial activities. The objective of this study is to investigate the functionalization of zinc oxide (ZnO) with chitosan to develop a novel ZnO@Ch adduct for use in cosmetic formulations, specifically as a sun protection agent. The functionalization was achieved through ionotropic gelation, which enhanced the stability and reduced the photocatalytic activity of ZnO, thereby improving its safety profile for skin applications. FTIR spectroscopy confirmed the successful functionalization, while TGA and DSC characterized the thermal properties and stability. The Zeta potential and particle size analyses demonstrated improved stability of ZnO@Ch across various pH levels compared to uncoated ZnO. The structure of the obtained adduct was also confirmed by SEM analysis. The ZnO@Ch adduct exhibited enhanced stability at neutral and slightly alkaline pH values, reduced photocatalytic activity compared to pure ZnO, and had lower cytotoxicity in 3T3 cells compared to pure ZnO, particularly at higher concentrations. The ZnO@Ch adduct provided a higher Sun Protection Factor (SPF) and UVA Protection Factor (UVA-PF) than pure ZnO, indicating enhanced UV protection. The adduct’s ability to provide higher SPF at lower ZnO concentrations offers economic and environmental benefits, aligning with sustainable product design principles. Future studies will focus on optimizing the formulation and testing the efficacy and safety at higher concentrations to fully realize its potential as a natural, eco-friendly sunscreen ingredient. Full article

Traditional sunscreens have relied on synthetic compounds to protect against harmful ultraviolet (UV) radiation. However, there is increasing interest in utilizing the natural photoprotective properties of microalgae extracts. This approach does not only aim to enhance the stability and efficacy of sun protection formulae but also seeks to reduce the reliance on synthetic sunscreens. This study investigates the encapsulation of Tisochrysis lutea extract (TL) in nanostructured lipid carriers (NLCs) to create a combination (NLC-TL) with enhanced physicochemical stability, antioxidant activity, SPF efficacy, wound healing capacity, and skin hydration. The particle size and ζ-potential were approximately 100 nm and −50 mV, respectively, and both formulations successfully passed the stability tests. The antioxidant activity, measured via DPPH assay, revealed that NLC-TL achieved the highest free radical scavenging activity across all tested concentrations, indicating a synergistic effect. The incorporation of TL in NLCs maintained the sun protection factor (SPF) of a 2% extract solution (1.53 ± 0.13). The wound healing assay indicated that NLC-TLs significantly enhanced wound closure compared to controls and TL alone. Additionally, skin hydration tests on healthy volunteers revealed that NLC-TLs provided superior and sustained hydration effects. These results highlight NLC-TLs’ potential as a multifunctional topical agent for cosmetic and therapeutic applications. Full article

Sunscreen products can protect the skin against the harmful effects of UV radiation, including reddening, aging, and cancer. The aim of this research was to evaluate the photoprotective effects of yeast pulcherrimin, an iron-chelating dipeptide. We first investigated the cytotoxicity of pulcherrimin produced by Metschnikowia pulcherrima yeast on the human keratinocyte HaCaT cell line, using the PrestoBlue assay. We assessed the ability of pulcherrimin to induce DNA repair after the exposure of HaCaT cells to oxidative stress. We also evaluated its protective activity against UVC radiation. The sun protective factor (SPF) was calculated using the Mansur equation. The UVA/UVB ratio values for pure pulcherrimin were evaluated using the Boots Star Rating system. The critical wavelength was determined by calculating the integrated optical density curve area. Based on the results, pulcherrimin shows strong cytoprotective effects through antioxidant and photoprotective activities on the HaCaT cell line. The calculated SPFs were 20 and 15 at pH = 7 and pH = 10, respectively. The critical wavelength above 370 nm and the UVA/UVB ratio R > 1 suggest that yeast pulcherrimin—a cyclic dipeptide containing iron—may be considered a promising photoprotective agent. Full article

A current trend in healthcare research is to discover multifunctional compounds, able to interact with multiple biological targets, in order to simplify multi-drug therapies and improve patient compliance. The aim of this work was to outline the growing demand for innovative multifunctional compounds, achieved through the synthesis, characterisation and SAR evaluation of a series of 2-styrylbenzothiazole derivatives. The six synthesised compounds were studied for their potential as photoprotective, antioxidant, antiproliferative, and anti-inflammatory agents. In order to profile antioxidant activity against various radical species, in vitro DPPH, FRAP and ORAC assays were performed. UV-filtering activity was studied, first in solution and then in formulation (standard O/W sunscreen containing 3% synthesised molecules) before and after irradiation. Compound BZTst6 proved to be photostable, suitable for broad-spectrum criteria, and is an excellent UVA filter. In terms of antioxidant activity, only compound BZTst4 can be considered a promising candidate, due to the potential of the catechol moiety. Both also showed exceptional inhibitory action against the pro-inflammatory enzyme 5-lipoxygenase (LO), with IC₅₀ values in the sub-micromolar range in both activated neutrophils and under cell-free conditions. The results showed that the compounds under investigation are suitable for multifunctional application purposes, underlining the importance of their chemical scaffolding in terms of different biological behaviours. Full article

Cutaneous squamous cell carcinoma (cSCC) is the second most common skin malignancy and poses a significant risk to immunosuppressed patients, such as solid organ transplant recipients and those with hematopoietic malignancies, who are up to 100 times more likely to develop cSCC compared with the general population. This review summarizes the current state of treatment for cSCC in immunosuppressed patients, focusing on prevention, prophylaxis, surgical and non-surgical treatments, and emerging therapies. Preventative measures, including high-SPF sunscreen and prophylactic retinoids, are crucial for reducing cSCC incidence in these patients. Adjusting immunosuppressive regimens, particularly favoring mTOR inhibitors over calcineurin inhibitors, has been shown to lower cSCC risk. Surgical excision and Mohs micrographic surgery remain the primary treatments, with adjuvant radiation therapy recommended for high-risk cases. Traditional chemotherapy and targeted therapies like EGFR inhibitors have been utilized, though their efficacy varies. Immunotherapy, particularly with agents like cemiplimab and pembrolizumab, has shown promise, but its use in immunosuppressed patients requires further investigation due to potential risks of organ rejection and exacerbation of underlying conditions. Treatment of cSCC in immunosuppressed patients is multifaceted, involving preventive strategies, tailored surgical approaches, and cautious use of systemic therapies. While immunotherapy has emerged as a promising option, its application in immunosuppressed populations necessitates further research to optimize safety and efficacy. Future studies should focus on the integration of personalized medicine and combination therapies to improve outcomes for this vulnerable patient group. Full article

Different lipid phase ratios (12, 14, and 16% w/w) were assessed for their ability to affect the technological and sensory properties of O/W emulsions in which bemotrizinol (BMTZ), a broad-spectrum sunscreen agent, was incorporated free or loaded into nanostructured lipid nanocarriers (NLC) to reduce its release from the vehicle and, hence, its skin permeation. The following technological properties were evaluated in vitro: spreadability, viscosity, pH, occlusion factor, BMTZ release, and sun protection factor (SPF). Sensory attributes were assessed by panelists in three different phases: before/during pick-up, rub-in, and after application. Raising the lipid phase ratio led to an increase in viscosity (from 8017 ± 143 cPs to 16,444 ± 770 cPs) and to a corresponding decrease in spreadability (from 9.35 ± 0.21 cm to 7.50 ± 0.10 cm), while the incorporation of BMTZ-loaded NLC determined a decrease in the occlusion factor (from 47.75 ± 1.16 to 25.91 ± 1.57) and an increase in SPF (from 6% for formulations containing 12% lipid phase to 15% for formulations containing 16% lipid phase). No BMTZ release was observed from all emulsions. Sensory attributes were mainly affected by the lipid phase ratio. These results suggest that the lipid phase ratio and BMTZ incorporation into NLC could contribute to determining the technological and sensory properties of O/W emulsions. Full article

Natural compounds are becoming increasingly popular in the fields of pharmaceuticals and cosmetics. One such compound is lignin, a plant-derived aromatic polymer that serves as a natural anti-ultraviolet agent. Conventional methods for extracting lignin from plant materials typically involve performing procedures in harsh environments, such as dissolving it in highly alkaline solutions or subjecting it to treatment in acidic conditions. In this study, lignin was extracted from coconut husk under milder conditions, using neutral solvents and ultrasonic treatment, which allowed us to obtain lignin with significantly improved properties. The developed method facilitated the creation of light-colored lignin, which was employed as a natural ingredient in sunblock cream. Furthermore, for the sake of comparison, lignin was extracted under more rigorous conditions using the traditional method. The research findings confirm that the light-colored lignin sample exhibits a higher level of UV absorption. Furthermore, light-colored lignin demonstrates a synergistic effect when combined with commercial moisturizing creams and sunscreens, leading to a significant enhancement in their SPF performance against both UVA and direct sunlight exposure. This study highlights the potential value of incorporating lignin as a valuable natural ingredient in sunblock and cosmetic products. Full article

The detrimental effects of ultraviolet radiation (UVR) on human skin are well-documented, encompassing DNA damage, oxidative stress, and an increased risk of carcinogenesis. Conventional photoprotective measures predominantly rely on filters, which scatter or absorb UV radiation, yet fail to address the cellular damage incurred post-exposure. To fill this gap, antioxidant molecules and DNA–repair enzymes have been extensively researched, offering a paradigm shift towards active photoprotection capable of both preventing and reversing UV–induced damage. In the current review, we focused on “active photoprotection”, assessing the state-of-the-art, latest advancements and scientific data from clinical trials and in vivo models concerning the use of DNA-repair enzymes and naturally occurring antioxidant molecules. Full article