Isoflavones are found in numerous plant species within the Leguminosae family; however, soy isoflavones are particularly significant in practice and have been extensively studied in recent years. The health-promoting potential of orally administered soy isoflavones is widely documented in the scientific literature, and many review articles have been developed to highlight their significance. However, it should be noted that soy-isoflavone-rich extracts and isolated soy isoflavones, such as genistein and daidzein, are also often applied topically as ingredients in many formulations, including face creams, tonics, and emulsions. New delivery systems are continuously being developed to enhance the skin permeability of isoflavones, thus improving their efficacy. In this context, their direct activity on skin cells is an important aspect of scientific research. The anti-inflammatory, protective, and antioxidant properties of isoflavones and soy extracts make them promising cosmetic ingredients with anti-aging potential because inflammation and the accumulation of reactive oxygen species (ROS) can lead to structural and functional changes in skin cells, accelerating the aging process. This review provides an overview of research on the impact of the application of soy isoflavone extract and soy-derived isoflavones on skin cells, with a focus on the documented molecular mechanisms underlying their effects. This study aims to offer essential insights to aid in the development of functional cosmetics and future clinical applications.

Silver is one of the most toxic heavy metals for plants, inducing various toxic symptoms and metabolic changes. Here, the impact of Ag(I) on Carlina acaulis physiology and selected metabolites was studied using two Ag concentrations (1 or 10 µM) after 14 days of exposure. The higher concentration of Ag(I) evoked reduction of growth, while 1 µM Ag had a growth-promoting effect on root biomass. The translocation factor (<0.04) showed that Ag was mainly retained in the roots. The 1 µM Ag concentration increased the level of low-molecular-weight organic acids (LMWOAs), while 10 µM Ag depleted these compounds in the roots. The increased concentration of Ag(I) elevated the accumulation of phytochelatins (PCs) in the roots and reduced glutathione (GSH) in the shoots (but not in the roots). At 1 µM, Ag(I) elevated the level of phenolic and triterpene acids, while the 10 µM Ag treatment increased the carlina oxide content in the roots. The obtained results indicate an alteration of metabolic pathways of C. acaulis to cope with different levels of Ag(I) stress. Our data imply that the intracellular binding of Ag(I) and nonenzymatic antioxidants contribute to the protection against low concentrations of Ag ions.

Polyphenols are valuable contributors to skin health, offering potent antioxidant and anti-inflammatory effects that help counteract the process of inflammaging. According to the literature, Urtica dioica L. is a rich source of polyphenolic compounds, suggesting its potential for applications in cosmetology and dermatology. This study aimed to evaluate the antioxidant and anti-inflammatory activity of polyphenol-rich fractions isolated from U. dioica leaves (UdLs) and flowers (UdFs) using human skin cells subjected to oxidative stress and lipopolysaccharide (LPS) stimulation, respectively. Extracts were obtained via an accelerated solvent extraction and further purified by a solid-phase extraction to concentrate their polyphenolic content. Their chemical composition was analyzed using UPLC-DAD-MS. Biological activity was assessed through cytotoxicity assays (NR and MTT), chemical and cellular antioxidant assays (DPPH, ABTS, FRAP, CUPRAC, TPC, and H₂DCFDA), an evaluation of antioxidant enzyme activity (SOD, CAT), lipid peroxidation (MDA), and cytokine production (IL-1β, IL-6, IL-10). Our study showed that both fractions were abundant in phenolic compounds, with chlorogenic acid identified as the predominant constituent. UdLs contained higher levels of phenolic acids, whereas the UdF was richer in flavonoids, particularly derivatives of isorhamnetin. Both the UdL and UdF were non-cytotoxic and exhibited strong radical scavenging potential, with the UdL being slightly more effective. They significantly reduced intracellular ROS levels, enhanced the activity of antioxidant enzymes, and attenuated lipid peroxidation in cells exposed to oxidative stress. Moreover, both fractions reduced the secretion of pro-inflammatory cytokines in LPS and H₂O₂-stimulated fibroblasts. These results highlight the potential of polyphenolic fractions derived from U. dioica leaves and flowers as multifunctional ingredients for anti-aging and skin-protective cosmetics.

Usnic acid (UA) is a compound with multiple biological activities that make it useful in various industries, e.g., pharmaceutical, cosmetic, dentistry, and agricultural sectors. Lichens are the primary source of UA, which is primarily extracted using acetone. This study aimed to investigate the solubility of UA in numerous natural deep eutectic solvents (NADESs) and use a mixture of thymol and camphor as a NADES in the optimization of the UA extraction process with the design of experiments method. For numerical optimization, the following parameters were employed in the experiment to confirm the model: a camphor-to-thymol ratio of 0.3, a liquid-to-solid ratio of 60, and a time of 30 min. The obtained experimental results aligned well with the predicted values, with the mean experimental value falling within the confidence interval, exhibiting deviations between 11.93 and 14.96. By employing this model, we were able to optimize the extraction procedure, facilitating the isolation of approximately 91% of the total UA content through a single extraction, whereas a single acetone extraction yielded only 78.4% of UA.