Ioannis Tsivintzelis

Pistacia lentiscus var. chia resin (Chios Mastic Gum—CMG) is a natural aromatic resin that has been utilized in traditional medicine for more than 2.5 millennia, as it exhibits a wide range of pharmacological properties. In this study, various quantities of Chios Mastic Gum (3.5, 6.5, and 10 wt%) were encapsulated in electrospun fibers of poly-ε-caprolactone (PCL) to develop functional fibrous mats with multiple potential applications. The morphological analysis of composite membranes was conducted through scanning electron microscopy (SEM), revealing the formation of uniform fibers and incremental diameter size in samples with a higher concentration of CMG. The encapsulation efficiency was assessed by UV-Vis spectrophotometry and showed an exceptionally high loading efficiency (87–88%). The cytotoxicity of CMG-loaded nanofibers was tested in human embryonic kidney cell line HEK293 and human hepatocarcinoma cell line HepG2 using the MTT assay. In both cases, a high concentration of encapsulated CMG led to a statistically significant reduction in cell viability.

In this work, we studied the thermal behavior and infrared fingerprint of anhydrous and hydrated DL-tartaric acid via conventional and modulated Differential Scanning Calorimetry (DSC), Thermogravimetry (TGA), Fourier Transform Infrared Spectroscopy (FTIR), nuclear magnetic resonance (NMR), pH measurements, and ab initio density functional theory (DFT) calculations. Six samples were examined in total (raw, recrystallized from D₂O solution, freeze-dried, and three heated samples). The results reveal that both forms (anhydrous and hydrated) do not exhibit melting prior to decomposition. It is also shown that the so-called DL-tartaric acid does not exist in the solid state in pure form, but it contains water and a tartaric acid oligomer, which is produced through esterification. Alteration of the chemical structure (reflected through decomposition) is initiated at quite low temperatures and is more pronounced for the hydrated form. Up to 75 °C, decomposition proceeds through esterification, while at higher temperatures it seems to be reversed due to the increase in water and decrease in COOH groups emerging through anhydride formation. Either upon heating or at sub-zero temperatures during freeze-drying, the hydrated form decomposes, and although some water is removed, new water is produced due to esterification. The conclusions are also supported by DFT calculations.

Silybin is a natural flavonolignan with potential anticancer, antioxidant, and hepatoprotective properties. In the present study, various loadings of silybin (1, 3, and 5 wt%) were encapsulated in poly-ε-caprolactone (PCL) fibers by electrospinning, in order to produce new pharmaceutical composites with improved bioactive and drug delivery properties. The morphological characteristics of the composite fibrous structures were evaluated by scanning electron microscopy (SEM), and the encapsulation efficiency and the release rate of silybin were quantified using a UV-Vis spectrophotometer. The analysis of the membranes’ thermal behavior by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) revealed the existence of interaction between PCL and silybin. An investigation of the cytocompatibility of the composite membranes revealed that normal cells displayed an unimpeded proliferation in the respective silybin concentrations; however, tumor cell growth demonstrated a dose-dependent inhibition. Furthermore, an effective antioxidant activity against hydrogen peroxide-induced oxidative stress in HEK-293 cells was observed for the prepared electrospun fibrous mats.