Products of natural origin have become important agents in the treatment of cancer, and the active principles of natural sources could be used in combination with chemotherapeutic agents to increase their effects and to minimize their toxicity. Oleanolic (OA) and ursolic (UA) acids are intensely studied for their promising anticancer potential. The aim of this study was focused on the in vitro toxicological effects induced by UA and OA human mesenchymal stem cells and on melanoma, one of the most frequent cancers whose incidence is increasing every year. The two compounds were tested for their cytotoxic, cell cycle arrest and pro-apoptotic effects on melanoma cells (A375 and B164A5) and mesenchymal stem cells. UA exerted a cytotoxic effect in a dose-dependent manner on melanoma cells, while OA’s activity has been shown to be low or moderate. Both compounds produced alterations of the cell cycle, arresting cells in the G0/G1 phase. Furthermore, UA induced significant apoptosis through the bcl-2 genes family pathway, with the decrease of the bcl-2 gene expression. The two compounds exerted selective effects on melanoma cells with no effects on human mesenchymal stem cells. The presented results reveal the anticancer potential of UA on melanoma cells, with no detectable toxicity on the mesenchymal stem cells.

Copper nanoparticles (CuNPs) have attracted attention due to their low cost and high specific surface area. In this work, a simple and inexpensive two-step synthesis method was proposed to prepare highly stable and well-dispersed spherical CuNPs in solution with a particle size of approximately 37 nm. Synthesis of CuNPs was carried on in the presence of complexing agent trisodium citrate (TSC), while for the chemical reduction step, sodium borohydride (NaBH₄) was used. Taking into account the potential of this type of nanoparticles, their synthesis and characterization represent a current and relevant topic in the field. The ability to control the size, shape and properties of CuNPs by adjusting the synthesis parameters (pH, precursor:stabilizer:reductant ratio, homogenization time, temperature) offers extraordinary flexibility in the development of these materials. The combination of characterization techniques such as SEM, EDX, UV–Vis, Raman, FT-IR and AFM provides a thorough understanding of the structure and properties of CuNPs, allowing the modulation of the properties of the obtained nanoparticles in the desired direction. Based on the studies, the copper reduction mechanism was proposed. For the theoretical verification of the size of the experimentally obtained spherical CuNPs, Mie theory was applied. A stability study of the synthesized CuNPs in optimal conditions was performed using UV–Vis analysis at specific time intervals (1, 3, 30 and 60 days), the sample being kept in the dark, inside a drawer at 25 °C. The CuNPs obtained after setting the optimal synthesis parameters (Cu(II):TSC:${\mathrm{B}\mathrm{H}}_4^{+}$ = 1:1:0.2, pH = 5, homogenization time 60 min and temperature 25 °C) were then tested to highlight their antibacterial effect on some reference bacterial strains. The obtained CuNPs demonstrated very good antimicrobial efficacy compared to traditional antimicrobials, for both Gram-negative and Gram-positive bacteria. This may reduce the development of antimicrobial resistance, an urgent medical issue. After evaluating the cytotoxic effects of CuNPs on the SKBR3 cancer cell line, a significant decrease in cell proliferation was observed at the 0.5 mg/mL concentration, with a reduction of 89% after 60 h of cultivation. Higher concentrations of CuNPs induced a more rapid cytotoxic effect, leading to an accelerated decline in cell viability.

Populus nigra L. is a plant from Salicaceae family, native in Europe. Many parts of this tree can be used as active ingredients, but the most valuable are the buds. In recent years, a growing number of studies reported their activity in the development of a wide range of pharmacological activities including diabetes, cardiovascular diseases, and cancer. The aim of this study was to determine the phytochemical composition and to evaluate the inorganic elements’ concentration as well as the in vitro antiproliferative and pro-apoptotic potential of a Populus nigra L. buds extract collected from Timișoara (Romania) against A549 human lung cancer cell line. Populus nigra L. bud extract was found to contain twelve different phenolic compounds. The inorganic elements concentrations were below the limit of detection for Co, Pb, and As, whereas Cu = 6.66 µg/g; Cr = 0.79 µg/g; Ni = 3.28 µg/g; Fe = 39.00 µg/g; Zn = 14.84 µg/g; Mn = 0.59 µg/g; Al = 2109.87 µg/g; and Cd = 0.019 µg/g. The extract was tested for the in vitro antiproliferative and pro-apoptotic potential on A549 human lung cancer cell line using different concentrations, namely 10, 25, 50, 75, 100, and 150 μg/mL. Results have shown that poplar bud extract induced a significant decrease of tumor cell viability in a dose-dependent manner with an IC₅₀ = 72.49 μg/mL and blocked the cells in the G0/G1 phase of the cell cycle. Phenomena of early apoptosis (from 1.34 ± 0.33% control cells to 2.68 ± 0.62% at 150 µg/mL) and late apoptosis (from 1.43 ± 0.14% control cells to 5.15 ± 1.02% at 150 µg/mL) were detected by Annexin V-PI double staining. Poplar bud extract can be regarded as a promising candidate for future studies involving lung cancer.

Quercetin is a natural flavonoid renowned for its potent antioxidant, anti-inflammatory, anti-diabetic, and antibacterial properties, making it a highly promising candidate for the treatment of various medical conditions. Our current study investigates the influence of quercetin on energy metabolism, fatty acid composition, oxidative stress gene expression, and sirtuin expression in early- and late-stage passages of stem cells derived from human exfoliated deciduous teeth (SHEDs). Mitochondrial respiration was analyzed by measuring oxygen consumption following a 24 h quercetin treatment, while fatty acid profiles were examined using gas chromatography–mass spectrometry (GC-MS). Additionally, quantitative PCR (qPCR) was used to assess the expression of oxidative stress genes and sirtuins. In younger SHEDs, quercetin enhances metabolic activity and mitochondrial respiration, although higher doses may decrease mitochondrial activity. Conversely, in older, senescent SHEDs, quercetin supports mitochondrial function at lower concentrations but appears to inhibit respiration at higher doses. These results suggest that quercetin may hold therapeutic potential for maintaining SHED viability and function, especially at lower doses in older cells. Further research is essential to fully elucidate a dose-dependent effect of quercetin and optimize its applications in regenerative medicine.

The metabolic regulation of stemness is widely recognized as a crucial factor in determining the fate of stem cells. When transferred to a stimulating and nutrient-rich environment, mesenchymal stem cells (MSCs) undergo rapid proliferation, accompanied by a change in protein expression and a significant reconfiguration of central energy metabolism. This metabolic shift, from quiescence to metabolically active cells, can lead to an increase in the proportion of senescent cells and limit their regenerative potential. In this study, MSCs from human exfoliated deciduous teeth (SHEDs) were isolated and expanded in vitro for up to 10 passages. Immunophenotypic analysis, growth kinetics, in vitro plasticity, fatty acid content, and autophagic capacity were assessed throughout cultivation to evaluate the functional characteristics of SHEDs. Our findings revealed that SHEDs exhibit distinctive patterns of cell surface marker expression, possess high self-renewal capacity, and have a unique potential for neurogenic differentiation. Aged SHEDs exhibited lower proliferation rates, reduced potential for chondrogenic and osteogenic differentiation, an increasing capacity for adipogenic differentiation, and decreased autophagic potential. Prolonged cultivation of SHEDs resulted in changes in fatty acid composition, signaling a transition from anti-inflammatory to proinflammatory pathways. This underscores the intricate connection between metabolic regulation, stemness, and aging, crucial for optimizing therapeutic applications.