Physchem

This study presents a systematic investigation of the dynamic and structural characteristics of St. John’s wort (Hypericum perforatum) in alcoholic solutions using experimental and theoretical techniques. Ultrasonic relaxation spectroscopy was employed to investigate medium-range dynamic processes, while density functional theory (DFT) calculations were employed to explore the molecular structure and vibrational properties of the system. Theoretical calculations revealed two Hyperforin conformers, a keto derivative, and three protonated species. Acoustic spectra revealed three distinct Debye-type relaxation processes, corresponding to conformational changes in hyperforin, enol-to-keto tautomerization, and proton transfer mechanisms. In addition, St. John’s wort oil (Oleum Hyperici) was studied, using attenuated total reflection (ATR) infrared spectroscopy for several extraction intervals. These spectra were compared with the theoretical IR spectra of hypericin, hyperforin, and its derivatives, confirming the presence of hyperforin, keto, and two protonated species in the oil. Besides structural and dynamical evaluations, the study assessed the toxicity and biological activity of hyperforin and all species found in the solutions, offering information about potential pharmaceutical uses, suggesting that hyperforin and its keto form have the best antidepressant activity. This comprehensive analysis enhances the understanding of hyperforin’s molecular behavior and strengthens the therapeutic potential of St. John’s wort as a natural antidepressant agent.

Polyethylene terephthalate-derived fluorescent carbon quantum dots (PET-CQDs) are promising nanomaterials for sensing and biomedical uses, yet their biological interactions after metal doping require careful evaluation. Here, we report an in silico assessment of pristine and dual-site (via graphitic [G] and carbonyl [O]) metal-doped PET-CQDs (Ca, Mg, Fe, Zn) using molecular docking against eight human proteins: HSA (distribution), CYP3A4 (metabolism), hemoglobin (systemic biocompatibility), transferrin (uptake), GST (detoxification), ERα (endocrine regulation), IL-6 (inflammation), and caspase-3 (cytotoxic signaling) together with ADMET profiling and DFT–docking correlation analysis. Docking affinities were compared with controls and ranged from −7.8 to −10.4 kcal·mol⁻¹ across systems, with binding stabilized by π–π stacking, hydrogen bonding and metal–ligand coordination involving residues such as arginine, tyrosine and serine. Importantly, top-performing CQD variants differed by target: PET-CQDs, MgG_PET-CQDs and FeG_PET-CQDs were best for GST; ERα interacted favorably with all doped variants; IL-6 bound best to CaO_PET-CQDs and FeO_PET-CQDs (≈−7.1 kcal·mol⁻¹); HSA favored CaG_PET-CQDs (−10.0 kcal·mol⁻¹) and FeO_PET-CQDs (−9.9 kcal·mol⁻¹); CYP3A4 bound most strongly to pristine PET-CQDs; hemoglobin favored MgG_PET-CQDs (−9.6 kcal·mol⁻¹) and FeO_PET-CQDs (−9.3 kcal·mol⁻¹); transferrin favored FeG_PET-CQDs; caspase-3 showed favored binding overall (pristine −6.8 kcal·mol⁻¹; doped −7.4 to −7.6 kcal·mol⁻¹). ADMET predictions indicated high GI absorption, improved aqueous solubility for some dopants (~18.6 mg·mL⁻¹ for Ca-O/Mg-O), low skin permeability and no mutagenic/carcinogenic flags. Regression analysis showed frontier orbital descriptors (HOMO/LUMO) partially explain selective affinities for ERα and IL-6. These results support a target-guided selection of PET-CQDs for biomedical applications, and they call for experimental validation of selected dopant–target pairs.

With the surging demand for high-performance energy storage devices, enhancing the energy density and charge-discharge efficiency of lithium-ion batteries has become an urgent need. Co₃O₄, with a high theoretical specific capacity of 890 mAh g⁻¹, is regarded as a promising anode candidate. In this work, rod-like hybrid Co₃O₄/SnO₂ composites were successfully prepared via the pyrolysis of cobalt-tin ethylene glycolate precursor. Notably, when the Co/Sn molar ratio is tuned to 3.8:1, the product evolves into nanorods. Lithium-ion batteries using Co_3.8Sn₁ as the anode deliver an initial specific capacity of 1588.9 mAh g⁻¹, and retain a reversible capacity of 427.9 mAh g⁻¹ after 500 cycles at 2 A g⁻¹, demonstrating that Sn-doping-induced optimization of morphology and conductivity effectively enhances electrochemical performance.