ASCORBIC ACID

The primary function of the skin is to act as a barrier against insults from the environment, and its unique structure reflects this. The skin is composed of two layers: the epidermal outer layer is highly cellular and provides the barrier function, and the inner dermal layer ensures strength and elasticity and gives nutritional support to the epidermis. Normal skin contains high concentrations of vitamin C, which supports important and well-known functions, stimulating collagen synthesis and assisting in antioxidant protection against UV-induced photodamage. This knowledge is often used as a rationale for the addition of vitamin C to topical applications, but the efficacy of such treatment, as opposed to optimising dietary vitamin C intake, is poorly understood. This review discusses the potential roles for vitamin C in skin health and summarises the in vitro and in vivo research to date. We compare the efficacy of nutritional intake of vitamin C versus topical application, identify the areas where lack of evidence limits our understanding of the potential benefits of vitamin C on skin health, and suggest which skin properties are most likely to benefit from improved nutritional vitamin C intake.

Cosmeceuticals containing antioxidants are among the most popular antiaging remedies. Topically applied antioxidants exert their benefits by offering protection from damaging free radicals produced when skin is exposed to ultraviolet light or allowed to age naturally. Vitamin C is a naturally occurring potent water-soluble antioxidant. Accordingly, it has been incorporated into a variety of cosmeceuticals designed to protect and rejuvenate photoaged skin. This article reviews the scientific data and clinical studies supporting the use of topically applied vitamin C for treating photoaged skin. Other innovative uses for vitamin C cosmeceuticals are also discussed. A significant body of scientific research supports the use of cosmeceuticals containing vitamin C. Cutaneous benefits include promoting collagen synthesis, photoprotection from ultraviolet A and B, lightening hyperpigmentation, and improvement of a variety of inflammatory dermatoses. Because of the diverse biologic effects of this compound, topical vitamin C has become a useful part of the dermatologist's armamentarium.

The aim of this study is to evaluate the effect of 2% chlorhexidine digluconate and a combination of 2.5% sodium hypochlorite with 10% ascorbic acid on fracture resistance of reattached fragments in primary and permanent anterior teeth. An in vitro study was conducted on 102 extracted human anterior teeth (51 primary and 51 permanent), allocated into six groups ( n = 17): Group A (primary incisors)-Conventional fragment reattachment, group B (primary incisors)-Chlorhexidine pretreatment, group C (primary incisors)-Sodium hypochlorite + ascorbic acid pretreatment, group D (permanent incisors)-Conventional fragment reattachment, group E (permanent incisors)-Chlorhexidine pretreatment, and group F (permanent incisors)-Sodium hypochlorite + ascorbic acid pretreatment. All specimens underwent standardized bonding, thermocycling (1,000 cycles, 5-55°C), and fracture testing in a universal testing machine. Data were analyzed with one-way analysis of variance (ANOVA) (SPSS v25, IBM, USA). In primary teeth, sodium hypochlorite-ascorbic acid showed the highest mean fracture resistance (54.63 ± 10.70 N), followed by chlorhexidine (52.43 ± 12.38 N) and conventional reattachment (43.19 ± 9.38N), with statistically significant differences. In permanent teeth, chlorhexidine demonstrated the highest mean value (151.63 ± 25.05 N), followed by conventional reattachment (145.73 ± 29.08 N) and sodium hypochlorite-ascorbic acid (130.92 ± 20.15 N), with no statistically significant differences among groups. Cavity disinfectants improve fracture resistance of reattached fragments, particularly in primary teeth. Sodium hypochlorite with ascorbic acid enhances bonding in primary dentition, while chlorhexidine provides consistent performance in both dentitions. Appropriate selection of cavity disinfectants based on dentition can improve the clinical success of fragment reattachment. Sodium hypochlorite followed by ascorbic acid may be beneficial in primary teeth by enhancing fracture resistance, while chlorhexidine can be safely used in permanent teeth without adversely affecting bond strength. This approach may contribute to improved longevity of restorations in pediatric trauma management.

Algae have shown an effective defense system that enables their survival in environments exposed to radiation stress, especially from ultraviolet (UV) light and ionizing radiation. Their protective system comprises specific photoprotective chemicals along with a multilayered antioxidant strategy that encompasses both non-enzymatic and enzymatic approaches. In this defence system, scytonemin and mycosporin-like amino acids play a crucial role in photoprotection by functioning as natural sunscreen with high photostability and strong UV-absorbing capacity. These chemical compounds also possess antioxidant properties that help minimize indirect damage produced by reactive oxygen species formed after radiation exposure. Scytonemin becomes significant due to its capability to block 90% of UV-radiation, effectively absorbing all types of UV (A, B and C) wavelengths. In the process of quenching photosensitization products and scavenging free radicals, carotenoids act as a stress reliever by preventing oxidative damage and lipid peroxidation. The internally generated ROS gets neutralized by algae, which utilize an enzymatic antioxidant system. In the enzymatic defence system of algae, ascorbate peroxidase, catalase, superoxide dismutase and glutathione reductase play important roles in ROS elimination. Additionally, α-tocopherol and ascorbic acid which are non-enzymatic antioxidants, complement the enzymatic reaction described above. The biochemical properties of these photoprotective and antioxidant compounds have significant biotechnological implications, applications in pharmaceuticals, cosmetics, anticancer treatments, nutraceuticals and antimicrobials. Interestingly, exposure to low-dose radiation has been shown to enhance algae growth, stimulate the production of valuable metabolites for biofuels and biomaterials and strengthen the resilience of cultivated strains against stressors.

The aim of this study was to analyze the effect of concomitant use of cannabigerol (CBG) and 3- O -ethylascorbic acid (EAA) on changes in the proteome of UVA-irradiated skin melanocytes, with particular emphasis on adduct formation between lipid peroxidation products and metabolically important proteins. Proteomic analysis allowed the identification of 1248 proteins with statistically significantly changed expression following melanocytes irradiation and/or incubation with CBG/EAA. The top 25 proteins with the most strongly differentially abundant expression included proteins involved in cell protection/antioxidant response, as well as pro-inflammatory and proapoptotic signalization. Moreover, in melanocytes irradiated with UVA, the levels of lipid peroxidation product, 4-hydroxynonenal (4-HNE) and its protein adducts were increased, as well as significant changes in the profile of proteins modified by 4-HNE were observed. CBG and EAA, especially when used together, largely reverse these effects. This study for the first time demonstrated the combined effect of CBG and EAA on the proteome of melanocytes after their exposure to UVA radiation, which applies to both changes in protein expression and intracellular signaling based on proteins modified by 4-HNE. It can be suggested that CBG and EAA may provide melanocytes with effective protection against the effects of oxidative stress and perhaps even protect the skin from carcinogenesis.

Organic ultraviolet absorbers （OUVAs） are a class of emerging contaminants that have garnered significant attention in recent years. In response to the characteristics of high detection frequency and low concentrations of OUVAs in water bodies， this study established an analytical method based on solid phase extraction （SPE） coupled with ultra-high performance liquid chromatography-tandem mass spectrometry （UHPLC-MS/MS） for the simultaneous determination of 16 OUVAs （nine UV stabilizers and seven UV filters） in drinking water. The 500 mL water sample was pretreated with 25 mg ascorbic acid， acidified to pH 2-3， and spiked with 1 mL of 5 μg/L mixed internal standard working solution. Target compounds were enriched and concentrated using an HLB solid phase extraction cartridge （200 mg/6 mL）. Separation was achieved on an Acquity Premier BEH C 18 column （100 mm×2.1 mm， 1.7 μm） using a gradient elution with methanol and 2 mmol/L ammonium acetate aqueous solution as the mobile phases. Detection was performed using electrospray ionization in positive mode and multiple reaction monitoring （MRM）， with quantification carried out by the internal standard method. The precision and accuracy of the established method were evaluated using drinking water as the matrix. The results showed that all 16 OUVAs exhibited good linearity within their respective mass concentration ranges， with correlation coefficients （ r ） greater than 0.992. The method detection limits （MDL， S/N= 3） were 0.03-5 ng/L， and the method quantification limits （MQL， S/N= 10） were 0.1-15 ng/L. At spiked levels of 5， 20 and 50 ng/L， the recoveries of the target analytes ranged from 75.0% to 130.6%， with relative standard deviations （RSDs） ranging from 0.9% to 12.9% （ n =6）. A total of seven source water samples and seven drinking water samples were analyzed using this method. The results showed that two OUVAs， 2-hydroxy-4-methoxybenzophenone （UV-9） and octocrylene （OC） were detected. In source water， the mass concentrations of UV-9 ranged from <MQL to 13.4 ng/L， while OC mass concentrations ranged from 5.0 to 32.23 ng/L. In drinking water， UV-9 was detected at 0.4 ng/L， and OC mass concentrations ranged from <MQL to 13.2 ng/L. This method is suitable for the trace analysis of 16 OUVAs in drinking water， demonstrating good accuracy and precision. It effectively improves the detection efficiency of OUVAs in water and can be used for the environmental monitoring and analysis of OUVAs in drinking water in China. 有机紫外吸收剂（OUVAs）是一类近年来备受关注的新污染物。本研究针对水体中OUVAs检出率高且含量低的特点，建立了一种基于固相萃取-超高效液相色谱-串联质谱同时检测生活饮用水中9种紫外稳定剂与7种紫外过滤剂的分析方法。在500 mL水样中先加入25 mg抗坏血酸，然后加入盐酸将pH调至2~3，再加入1 mL 5 μg/L的混合内标工作液，用HLB固相萃取柱（200

Transdermal drug delivery (TDD) is a non-invasive and painless drug delivery method, making it a compelling alternative to conventional methods, such as oral intake and intravenous injection. Although TDD holds promise, it faces challenges owing to the complex structure of the human skin. In particular, the stratum corneum (SC) serves as a significant barrier to drug absorption, hindering the passage of larger molecules. The TDD of vitagen, a stable L-ascorbic acid derivative with antioxidant properties, remains challenging because of its limited skin permeability. To address this issue, we prepared an ionic complex between vitagen and a synthesized guanidine-rich molecular transporter, scyllo-inositol-G6 (scyllo-G6), as a permeation enhancer (vitagen/scyllo-G6). This ionic complex showed improved skin permeability compared to vitagen alone with negligible cytotoxicity, indicating that the molecular transporter is biocompatible. Franz cell diffusion experiments demonstrated that scyllo-G6 exhibited a higher penetration coefficient with vitagen than other common penetration enhancers, such as oleic acid and menthol. Additionally, our findings revealed that the vitagen/scyllo-G6 complex had a notably greater inhibition effect on intracellular reactive oxygen species (ROS) than when vitagen was complexed to other permeation enhancers. Furthermore, FITC-labelled vitagen (FITC-vitagen) complexed with scyllo-G6 (FITC-vitagen/scyllo-G6) exhibited improved cellular uptake and penetrated deeper into tissue sections in a mouse model than FITC-vitagen conjugated to an arginine hexamer (Arg6), indicating that scyllo-G6 is a more effective skin penetration enhancer than Arg6. These findings suggest that utilizing scyllo-G6 as molecular transporter to enhance the skin permeability of vitagen is a promising strategy for TDD of vitagen.

Corn husk, a prevalent agricultural byproduct, remains an underutilized source of bioactive compounds. This study investigated the influence of extraction solvents (water, 50% ethanol, and 95% ethanol) and techniques (maceration, reflux, ultrasound-assisted extraction) on the phytochemical profiles and biological activities of corn husk. The results revealed that water extraction produced the highest total phenolic content, whereas 95% ethanol extraction yielded the greatest total flavonoid content and the most potent antioxidant activity in DPPH testing. In contrast, ultrasound-assisted water extraction exhibited the most potent nitric oxide inhibition (94.62 ± 2.13%) and tyrosinase inhibition (IC 50 = 7.54 ± 0.27 mg/mL), indicating anti-inflammatory and skin-lightening potential. This extract showed anti-collagenase activity (91.49 ± 4.01%), outperforming ascorbic acid (29.79 ± 1.00%) and EGCG (82.27 ± 1.00%), though its anti-hyaluronidase activity was limited. Cytotoxicity testing revealed cytotoxicity at 10 mg/mL, while the HET-CAM assay confirmed non-irritation at the same level. These findings underscore that ultrasound-assisted water extraction is a safe and successful technique for obtaining bioactive-rich extracts. This study supports the transition of corn husk from agricultural waste to a high-value, safe, and multifunctional natural ingredient for the cosmetic, pharmaceutical, and functional food industries.

Tissue engineering using the self-assembly approach represents a promising technology. However, age-related reductions in extracellular matrix deposition by stromal cells limit the mechanical robustness of reconstructed tissues what can be critical for midurethral sling reconstruction. Indeed, stress urinary incontinence predominantly affects women over 50 years of age and is commonly treated by implantation of midurethral slings, whose synthetic versions have raised concerns regarding safety and long-term tolerance. In this study, we investigated whether biochemical modulation could enhance collagen deposition and mechanical properties of self-assembled dermal tissues reconstructed from female donors of different ages. Dermal fibroblasts were cultured in the presence of ascorbic acid, and the effects of hormonal supplementation, metabolic and hypoxia-related stimuli, and insulin signaling activation were evaluated using collagen quantification, histological analyses, and mechanical testing. Fibroblasts derived from younger donors deposited significantly more collagen than those from older female donors. Among all tested conditions, insulin like growth factor 1 (IGF 1) markedly increased collagen deposition in a dose-dependent manner, including in fibroblasts from women over 50 years of age, whereas β-estradiol and progesterone had no significant effect on collagen content. Although β-estradiol slightly increased tissue thickness, only IGF-1 supplementation resulted in substantial improvements in perforation strength, stiffness, displacement at break, and toughness. These results demonstrate that IGF-1 is a potent enhancer of extracellular matrix production and mechanical performance in dermal tissues reconstructed by the self-assembly approach, and represents a promising strategy to improve the development of biological midurethral slings.

The rising prevalence of multidrug-resistant (MDR) pathogens necessitates the development of sustainable, biocompatible antimicrobial agents. Green synthesis of metal oxide nanoparticles using endophytic microorganisms offers an eco-friendly and bioactive alternative to conventional physical and chemical methods. In this study, zinc oxide nanoparticles (ZnO NPs) were biosynthesized using the cell-free supernatant of Streptomyces werraensis, a novel endophytic actinobacterium isolated from the medicinal plant Passiflora caerulea L. The formation of ZnO NPs was monitored via UV-visible spectroscopy and Fourier Transform Infrared (FTIR) spectroscopy. Morphological and structural characterizations were performed using Transmission Electron Microscopy (TEM), Selected Area Electron Diffraction (SAED), and Dynamic Light Scattering (DLS). The biological potential of ZnO NPs for human health was evaluated through antibacterial assays against a panel of human pathogens and antioxidant assays (DPPH and ABTS). UV-Vis spectra confirmed ZnONP formation with a characteristic band-gap absorption, while FTIR identified proteinaceous and phenolic capping agents. TEM and SAED revealed highly crystalline, predominantly spherical nanoparticles with an average diameter of 136 nm and a wurtzite crystal structure. The biosynthesized ZnO NPs exhibited potent, concentration-dependent antibacterial activity, particularly against Gram-negative strains; Salmonella paratyphi A and Proteus vulgaris showed maximum inhibition zones of 19.0 ± 0.64 mm and 16.4 ± 0.68 mm, respectively, which are comparable to those of commercial ampicillin. Antioxidant assays demonstrated significant radical-scavenging potential, with an IC50 of 22.15 ± 1.2 µg/mL in the ABTS assay, approaching that of ascorbic acid. The findings of the present study demonstrate that S. werraensis-mediated ZnO NPs serve as effective "nanogenerators" of oxidative stress, offering a dual-action therapeutic approach. These results highlight the potential of endophytic actinobacteria as sustainable bio-factories for producing functional nanoparticles with promising antimicrobial potential for treating MDR infections.

Achieving early and sensitive detection of esophageal cancer-related biomarkers in community healthcare settings is of great significance for the early screening, diagnosis, and intervention of diseases. This work developed a paper-based photoelectrochemical (PEC) immunosensing array loaded with thermally annealed ZnO nanocatalysts for the sensitive detection of ferritin, a biomarker of ferroptosis associated with the esophageal cancer, in community healthcare settings. A paper-based three-electrode system was mass-produced using screen printing technology, and thermally annealed ZnO nanocatalysts with excellent resistance to photo-corrosion were obtained and loaded onto the working electrode surface. The opposite region of the electrode was modified with ferritin-specific antibodies to enable target-specific capture and signal conversion. A one-step folding strategy was employed to directionally transfer the catalytic product, ascorbic acid, to the electrode interface, where it efficiently converts the biological signal into a photoelectric signal under excitation from a handheld flashlight. This sensor array demonstrated a wide linear detection range (0.1 - 50 ng mL -1 ) and a low detection limit (0.038 ng mL -1 ), while offering the advantages of low cost (1.0 $ per test), portability, and mass producibility. This work provides a rapid and reliable diagnostic tool for the early screening of esophageal cancer-related diseases in community settings.