This study reports the effective reuse of coffee residues from roasting and brewing processes using microwave-assisted extraction (MAE) of bioactive compounds. Principal Component Analysis (PCA) showed a significant impact (p < 0.001) on phenolic acid and alkaloid amounts among coffee (green and roasted) and its by-products (silver skin and spent grounds). Furthermore, a linear mixed-effects model identified that, apart from sample type, extraction temperature (50 and 70 °C) and ethanol volume fractions (50 and 70%, v/v) considerably influenced the quantities of bioactive compounds. The best conditions were achieved using 70% (v/v) ethanol at 70 °C. In addition to caffeine and chlorogenic acid, which were found in the highest amounts, the coffee and by-product samples contained high levels of total fibre (20.7–27.8%) and total fat (1.5–12.4%). Fatty acid analysis showed a dominance of oleic acid (7.55–12.7%), palmitic acid (19.3–40.3%), and linoleic acid (15.6–41.8%), with their saturated and unsaturated nature confirmed by Fourier Transform Infrared (FTIR) Spectroscopy. The reported data highlight the potential of coffee by-products as high-value sources for bioactive compound recovery.

Background/Objectives: Resveratrol (RSV) and curcumin (CRC) have antioxidant, anti-inflammatory, photoprotective, and cell-repairing properties. We selected them to investigate the potential role involved in human keratinocyte protection. Additionally, we tried to overcome the limitations of their application due to poor pharmacokinetics by introducing ferrocene into their structure. Methods: The multiple cellular endpoints—viability (determined by MTT and Trypan Blue method), ROS (reactive oxygen species) formation (evaluated by fluorescence intensity measurement), apoptosis and autophagy (assessed using flow cytometry) of trans-3,5,4′-tri(4-ferrocenylbutanoyloxy)-stilbene (RF) and (E)-5-(4-hydroxy-3-methoxyphenyl)-1-ferrocenylpent-4-ene-1,3-dione (CF), as well as of RSV and CRC, were evaluated in the HaCaT cell line. Results: RF and CF showed significantly lower antiproliferative activity, and cell survival was markedly pronounced compared to RSV or CRC-treated cells. CRC exerted the highest cytotoxicity, and cell viability was almost completely impaired at >50 µM. All compounds showed a beneficial effect on the reduction of ROS induced by tBHP (tert-butyl hydroperoxide), while in UV (ultraviolet) experiments, results were inconclusive (variable depending on dose). CRC and CF had the most prominent antioxidant capacity. Cytofluorimetry showed that CRC has a diverse range of targets in HaCaT cells, including cell proliferation arrest, apoptosis, and autophagy induction. RF at the lowest dose (5 µM) slightly induced autophagy, while treatment with CF even led to a decrease in the autophagy induction ratio. Conclusions: Based on the results, introducing ferrocene into natural compounds is an appropriate approach to protect skin cells, considering the low cytotoxicity of ferrocene-modified polyphenols and their retained antioxidant ability. However, caution should be exercised with CRC at ≥20 µM as it significantly impairs cell viability and induces cell death.

Polychlorinated biphenyls (PCBs) can induce neurotoxicity, immunotoxicity, reproductive toxicity, genotoxicity, and carcinogenicity (IARC group 1 Carcinogens). Scientific data suggest that resveratrol possesses the ability to attenuate ortho-PCB-induced toxicity. Recently, a novel ferrocene-containing triacyl derivative of resveratrol (RF) was synthesized and in this study, its potential to protect CHO-K1 cells from selected PCB congeners (75 µM) was evaluated. Cell viability/proliferation was observed by Trypan Blue (TB), Neutral Red (NR), Kenacid Blue (KB), and MTT bioassays, ROS formation by fluorescent probes, and the extent of apoptosis by flow cytometry. All applied bioassays confirmed that RF (2.5–100 μM) remarkably improves viability in PCB 153-treated cells with an increase in cell survival almost up to control levels. This effect was not determined after PCB 77 exposure, although ROS formation was decreased at RF ≥ 50 µM. Apoptosis was significant (p < 0.05) for both congeners. In PCB 77-treated cells, RF did not suppress the induction of cell death. The intended protective effect of RF was evident when cells were treated with PCB 153, and this correlates with results obtained for cell viability. Compared to resveratrol, the novel RF showed promising results in terms of improved biological activity and cell protection against PCB 153 toxicity at all concentrations tested.

This study examines the development and characterisation of sustainable, bio-functional films based on a pectin matrix enriched with spent coffee grounds (SGs) extract. The physicochemical and mechanical properties of the resulting films were evaluated as a function of pectin, plasticiser (glycerol), cross-linker (calcium chloride), and solvents (water, water/ethanol mixture), and different proportions of SG extract (5%, 10% and 20%). Combining 20% SG extract with 50% glycerol yielded the highest total phenol content, 11.4 mg/g, in the pectin-based film. After dissolving pectin in SG extracts, neither their fraction nor the glycerol mass fraction (50% and 70%) significantly altered the water solubility index (WSI) or the water absorption index (WAI) compared with the extract-free control films. However, the WSI and WAI values for the pectin-based films without SG extracts confirmed that the combination of 1.5% pectin, 1% calcium chloride and 50% glycerol provided the optimal results among the different extract-free formulations. This stability was further enhanced by the water/ethanol solvent system and the competitive binding of coffee phenolics, which limited moisture retention. This reduced hydration state and the formation of strong intermolecular hydrogen bonds within the functionalised matrix was confirmed by FTIR analysis. Colorimetric analysis showed that the solvent type, i.e., water and water/ethanol mixture, governed all colour parameters, and the addition of SG extract affected only the lightness value (L* = 31.98–32.61). Furthermore, mechanical strength was primarily determined by the structural density of the pectin network, with higher pectin contents significantly enhancing deformation and fracture resistance. Overall, the results showed that SG can be successfully used to develop a functional pectin-based film, providing a sustainable alternative to synthetic food packaging.