2025-12-26
Izaz Ahmad, Muhammad Atif, Gulmaira Aldibekova, Didara Balpanova, Humaira Zafar, Maria Sadia, Mushtaq Ahmad, Atia-tul-Wahab, Bates Kudaibergenova, uhammad Iqbal Choudhary
Estrogen plays a critical role in the development and progression of hormone-sensitive breast cancer. Aromatase (CYP19A1), the key enzyme catalyzing the final step in estrogen biosynthesis, has emerged as a promising therapeutic target. Although third-generation synthetic aromatase inhibitors (AIs) are effective, their use is limited by serious side effects, highlighting the need for safer natural alternatives. In this study, we evaluated three major flavonoids from Tussilago farfara L., quercetin-3-rutinoside (1), quercetin-3-O-β-D-glucoside (2), and kaempferol-3-O-glucoside (3) for aromatase inhibitory potential. In vitro assays showed that compound 3 was the most potent (IC 50 = 3.46 µM), followed by compound 2 (3.79 µM) and compound 1 (3.81 µM), with activities comparable to potent dietary flavonoids and stronger than some reported natural analogues. Molecular docking supported these findings, showing favourable docking scores (-6.73 to -4.19) and binding energies (-60.3 to -43.7 kcal mol -1 ), comparable to those of the standard inhibitor exemestane (IC 50 = 0.20 µM; -68.3 kcal mol -1 ). However, the computational predictions did not fully replicate the experimental ranking, reflecting the limitations of docking methods. Overall, these results highlight the significance and therapeutic potential of T. farfara flavonoids as natural aromatase inhibitors.
2025-12-26
O.A. Nurkenov, S.D. Fazylov, A.K. Syzdykov, Z.M. Muldakhmetov, A.R. Kovrizhina, A.I. Khlebnikov, T.M. Seilkhanov, S.K. Kabiyeva, A.T. Takibayeva, A.Zh. Mendibayeva
This study investigates the formation and characteristics of inclusion complexes between β-cyclodextrin and two compounds: N-aminomorpholine hydrazone and its phthalimidine derivative. Structural features of the encapsulated forms of these new N-aminomorpholine derivatives were characterized using 1 H and 13 C NMR spectroscopy, as well as two-dimensional 1 H─ 1 H (COSY) and 1 H─ 13 C (HMBC, HSQC) NMR experiments. Using molecular modeling methods, the influence of structural factors and the principle of geometric complementarity on the complexation processes between the host and guest molecules were assessed. A conformational study of the guest molecules was carried out using the semiempirical GFN2-xTB method in combination with the GOAT algorithm. Employing density functional theory (DFT), the inclusion complexes were optimized at the ωB97X-D/6-311G(d,p) level, including aqueous solvation effects as described by the CPCM model. The thermodynamic parameters of complex formation were estimated. NMR analysis confirmed 1:1 stoichiometry and showed significant chemical shift perturbations for cavity protons, while DFT calculations revealed spontaneous complexation (ΔG ° 298 = −2.54 to −3.45 kcal/mol) driven by exothermic enthalpies and hydrophobic/van der Waals interactions, with an enantioselective preference for the R-phthalimidine enantiomer. These findings demonstrate β-CD's potential to enhance the solubility, stability, and bioavailability of these promising antiviral and antibacterial agents for pharmaceutical applications.
2025-12-26
Gennadii Snizhnoi, Tatiana Pulina, Natalia Solidor, Gulmira Yar-Mukhamedova, Akmaral Imanbayeva, Daniel Zellele, Gauhar Mussabek
The article examines the patterns and mechanisms of pitting corrosion in AISI 321 and 08Kh18N10T stainless steels under conditions simulating recycled waters used in heat exchanger operation. It was established that the critical pitting temperature (CPT) of these steels increases significantly with increasing pH and decreasing chloride concentration in model solutions. The influence of the structural components of the steels was found to be less significant than that of the chloride-containing environment and to depend strongly on its parameters (pH and chloride concentration). In acidic model recycled waters (pH 4), AISI 304 steels – which contains minimal amounts of titanium nitrides, aluminum oxides, and carbon – exhibits the highest CPT values, regardless of the chloride concentration in the range of 350–600 mg/L. In contrast, AISI 321 and 08Kh18N10T steels, characterized by the highest volume fractions of titanium nitrides, as well as melt 2 of AISI 321 steel and 12Kh18N10T steel with elevated carbon content, show the lowest CPT values. Based on an analysis of the literature, it is hypothesized that this behavior may be attributed to the increased overvoltage of hydrogen ionization on titanium nitrides and carbonitrides, which act as initiation sites for pit formation and propagation. Additionally, the corrosion rate was found to correlate with the specific paramagnetic susceptibility χ 0 of austenite, a parameter reflecting the atomic magnetic state and determined by the chemical composition and phase structure of the alloy.