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.

Urtica dioica L. is one of the most widely utilized medicinal plants commonly applied in the form of tea, juice, and dietary supplements. This study aimed to assess the effect of the U. dioica ethanol–water extract (UdE) and polyphenolic fraction isolated from the extract (UdF) on normal human colon epithelial cells and to evaluate their protective activity against induced oxidative stress. The cytotoxic potential against human colorectal adenocarcinoma (HT29) and the anti-inflammatory effects were also investigated. UPLC-MS-DAD analysis revealed that both extracts were abundant in caffeic acid derivatives, specifically chlorogenic and caffeoylmalic acids, and therefore, they showed significant protective and ROS scavenging effects in normal human colon epithelial cells. Moreover, they had no negative impact on cell viability and morphology in normal cells and the extracts, particularly UdF, moderately suppressed adenocarcinoma cells. Furthermore, UdF significantly decreased IL-1β levels in HT29 cells. Our research indicates that U. dioica may provide significant health advantages because of its antioxidant and anti-inflammatory effects.

Ocimum basilicum is a valuable plant widely consumed worldwide and considered a rich source of polyphenols. This study examined the impact of the polyphenolic fraction isolated from basil (ObF) on human normal colon epithelial cells and human colorectal adenocarcinoma cells, evaluating its anti-inflammatory and protective activity against oxidative stress. The phytochemical characterization of the fraction was performed using ultra-performance liquid chromatography (UPLC) with a photodiode detector (DAD) and mass spectrometry (MS). UPLC-DAD-MS revealed that ObF predominantly contains caffeic acid derivatives, with rosmarinic acid and chicoric acid being the most abundant. The fraction demonstrated high antioxidant potential, as shown by DPPH assays, along with significant reducing power (FRAP). Furthermore, it prevented the depletion of antioxidant enzymes, including superoxide dismutase and catalase, and decreased malonylodialdehyde (MDA) in induced oxidative stress condition. Additionally, it exhibited a significant protective effect against H₂O₂-induced cytotoxicity in human normal colon epithelial cells. Although it had no impact on the viability of adenocarcinoma cells, it significantly reduced IL-1β levels in the neoplastic microenvironment. Our study demonstrated that basil polyphenols provide significant health benefits due to their antioxidant and protective activities.

Recently, there has been an increased interest in the valorization of byproducts generated during fruit processing. An example of this is the waste produced during the processing of strawberries. For instance, it has been evidenced that strawberries seeds can be a valuable source of oil. The goal of this paper was to investigate the potential of strawberry seed residues after oil extraction (defatted seeds) as a source of phenolics with possible cosmetic applications. The components were recovered using water and ethanol mixture, assisted by heat, ultrasound, and microwave. The extracts were characterized through ultra-high performance liquid chromatography with spectrophotometric and mass detectors (UPLC-DAD-MS), and the biological properties of the phenolic-rich fraction were assessed using antioxidant tests and a cell viability assay on human skin fibroblasts. The study revealed that defatted strawberry seeds are rich in low molecular weight phenolics, specifically in tiliroside, kaempferol 3-glucoside, and ellagic acid. Furthermore, the phenolic-rich fraction was effective in scavenging free radicals in human skin fibroblasts and showed cytoprotective activity against oxidative stress. This evidence suggests that defatted strawberry seeds are a valuable material for further processing to obtain a beneficial additive for skincare products.

Urtica dioica is a species with well-established significance in folk medicine in many countries. It was utilized to support the treatment of arthritis, allergies, and urinary tract disorders; however, the substantial presence of antioxidants suggests that nettle extract could also have a positive impact on the skin. The objective of this study was to assess the impact of nettle extract on human skin fibroblasts subjected to oxidative stress. Various solvents were tested to prepare an extract rich in polyphenolic compounds with high antioxidant potential. The chemical composition was determined using ultra-high-performance liquid chromatography with mass spectrometry (UPLC-DAD-MS). H₂O₂ treatment was used to induce oxidative stress and cell viability, and the metabolism was evaluated through NR and MTT assays. Our study demonstrated that extraction with 80% ethanol, followed by the drying and re-dissolving of the extract in pure water, was more efficient than direct extraction with water. This yielded an extract rich in polyphenolic compounds, with chlorogenic acid and caffeoylmalic acid as the predominant compounds, averaging 64.9 and 114.4 µg/mL, respectively. The extract exhibited antioxidant properties in the DPPH and ABTS assays. Furthermore, it did not exhibit cytotoxicity and did not negatively affect cell metabolism. In addition, it effectively reduced ROS in the H₂O₂-stimulated cells, and at the highest concentration tested, the ROS levels returned to those of the untreated control. The extract also protected against H₂O₂-induced cytotoxicity. The cell viability was maintained at the level of the untreated control when the cells were pretreated with the extract before H₂O₂ exposure. These findings indicate that U. dioica extract is a valuable and safe additive in skincare products.

Tiliroside is a natural polyphenolic compound with a wide range of biological activity, and defatted strawberry seeds are its rich source. The goal of this study was to optimize accelerated solvent extraction (ASE) conditions, including temperature, solvent composition, and the number of extraction cycles, using Box–Behnken design to maximize the yield of tiliroside. UPLC-DAD-MS was applied to investigate the polyphenolic composition of the extracts, and preparative liquid chromatography (pLC) was used for isolation. All obtained mathematical models generally showed an increase in the efficiency of isolating polyphenolic compounds with an increase in temperature, ethanol content, and the number of extraction cycles. The optimal established ASE conditions for tiliroside were as follows: a temperature of 65 °C, 63% ethanol in water, and four extraction cycles. This allowed for the obtainment of a tiliroside-rich fraction, and the recovery of isolated tiliroside from plant material reached 243.2 mg from 100 g. Our study showed that ASE ensures the isolation of a tiliroside-rich fraction with high effectiveness. Furthermore, defatted strawberry seeds proved to be a convenient source of tiliroside because the matrix of accompanying components is relatively poor, which facilitates separation.