Olive mill wastewater (OMWW), with its high level of phenolic compounds, simultaneously represents a serious environmental challenge and a great resource with potential nutraceutical activities. To increase the knowledge of OMWW’s biological effects, with an aim to developing a food supplement, we performed a chemical characterisation of the extract using the Liquid Chromatography–Quadrupole Time-of-flight spectrometry (LC–QTOF) and an in vitro genotoxicity/antigenotoxicity assessment on HepaRG ™ cells. Chemical analysis revealed that the most abundant phenolic compound was hydroxytyrosol. Biological tests showed that the extract was not cytotoxic at the lowest tested concentrations (from 0.25 to 2.5 mg/mL), unlike the highest concentrations (from 5 to 20 mg/mL). Regarding genotoxic activity, when tested at non-cytotoxic concentrations, the extract did not display any effect. Additionally, the lowest tested OMWW concentrations showed antigenotoxic activity (J-shaped dose–response effect) against a known mutagenic substance, reducing the extent of DNA damage in the co-exposure treatment. The antigenotoxic effect was also obtained in the post-exposure procedure, although only at the extract concentrations of 0.015625 and 0.03125 mg/mL. This behaviour was not confirmed in the pre-exposure protocol. In conclusion, the present study established a maximum non-toxic OMWW extract dose for the HepaRG cell model, smoothing the path for future research.

Background: Staphylococcus aureus is a highly lethal Gram-positive bacterium that is responsible for over one million deaths annually. As a member of the ESKAPE pathogens, its methicillin-resistant strains (MRSA) are prevalent worldwide and exhibit significant antimicrobial resistance (AMR). Bacterial efflux pumps play a pivotal role in the development of AMR by facilitating the expulsion of a range of antimicrobial agents. Methods: The S. aureus strain SA-1199B, which overexpresses NorA and carries a GrlA mutation, was utilized to comprehensively profile the mechanism of the compounds PQQ16P and PQK4F. To assess the toxicity and genotoxicity of these compounds, RAW macrophages, HEK 293T, and HepG2 cell lines were utilized. Female BALB/c mice were utilized to assess the in vivo synergism of EPIs with CPX, Results: NorA efflux pump inhibitors (EPIs), PQQ16P and PQK4F, enhanced the efficacy of the antibacterial ciprofloxacin (CPX) against resistant S. aureus strains. The mechanism of EPIs involved the inhibition of NorA efflux pump, without compromising bacterial membrane permeability, ATP levels, or mammalian calcium channels. Moreover, the EPIs significantly augmented the bactericidal and post-antibiotic effects of CPX, elevating its mutation prevention concentration without manifesting substantial toxicity to human cells. Furthermore, the EPIs reduced S. aureus invasiveness in macrophages, indicating a role for NorA in bacterial virulence. Notably, the in vivo synergism of these EPIs with CPX was observed in a mouse infection model. Conclusions: This study provides substantial evidence for the potential of employing EPIs in a combination with CPX to counteract AMR, both in vitro and in vivo.

Background: Staphylococcus aureus is a highly lethal Gram-positive bacterium that is responsible for over one million deaths annually. As a member of the ESKAPE pathogens, its methicillin-resistant strains (MRSA) are prevalent worldwide and exhibit significant antimicrobial resistance (AMR). Bacterial efflux pumps play a pivotal role in the development of AMR by facilitating the expulsion of a range of antimicrobial agents; Methods: The S. aureus strain SA-1199B, which overexpresses norA and carries a GrlA mutation, was utilized to comprehensively profile the mechanism of the compounds PQQ16P and PQK4F. To assess the toxicity and genotoxicity of these compounds, RAW macrophages, HEK 293T, and HepG2 cell lines were utilized. Female BALB/c mice were utilized to assess the in vivo synergism of EPIs with CPX; Results: NorA efflux pump inhibitors (EPIs), PQQ16P and PQK4F, enhanced the efficacy of the antibacterial ciprofloxacin (CPX) against resistant S. aureus strains. The mechanism of EPIs involved the inhibition of NorA efflux pump, without compromising bacterial membrane permeability, ATP levels, or mammalian calcium channels. Moreover, the EPIs significantly augmented the bactericidal and post-antibiotic effects of CPX, elevating its mutation prevention concentration without manifesting substantial toxicity to human cells. Furthermore, the EPIs reduced S. aureus invasiveness in macrophages, indicating a role for NorA in bacterial virulence. Notably, the in vivo synergism of these EPIs with CPX was observed in a mouse infection model; Conclusions: This study provides substantial evidence for the potential of employing EPIs in a combination with CPX to counteract AMR, both in vitro and in vivo.

Background/Objectives: Genetic variation in bitter taste receptors, particularly TAS2R38, influences sensitivity to bitter compounds such as 6-n-propylthiouracil (PROP). However, its influence on food preferences and dietary habits remains unclear. This study investigated the relationship between TAS2R38 rs713598 polymorphism, a variant in strong linkage disequilibrium with other common variants and therefore served as a proxy for TAS2R38 bitter taste-related genetic variation, PROP responsiveness, food preferences, and adherence to the Mediterranean diet. Methods: A cross-sectional molecular epidemiological study was conducted on 200 Italian adults. Participants completed questionnaires assessing food preferences, Mediterranean diet adherence (energy-restricted Mediterranean Diet Adherence Screener; er-MEDAS), and physical activity (IPAQ). Bitter taste perception was evaluated using the PROP test and a Labelled Magnitude Scale. Saliva samples were collected for TAS2R38 rs713598 genotyping by qPCR. Associations were analysed using Spearman’s correlation and generalised linear models. Results: Genotyping was completed for 176 participants. A significant positive correlation was found between rs713598 genotype and PROP sensitivity (ρ = 0.404, p < 0.01). Women showed higher PROP responsiveness than men. No significant associations were observed between PROP responsiveness or TAS2R38 genotype and either food preferences or Mediterranean diet adherence. Older age was associated with greater preference for bitter foods (p = 0.008), whereas higher physical activity and non-smoking status were associated with greater adherence to the Mediterranean diet (p = 0.020 and p = 0.024, respectively). Conclusions: TAS2R38 polymorphism influenced bitter taste perception but showed limited relevance for food preferences and dietary habits. Lifestyle factors appeared more influential in shaping dietary behaviour.