Browsing by Issue Date, starting with "2025-05-14"
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- Assessing the antimicrobial activity of essential oils against skin microorganisms using flow cytometryPublication . Lopes, Ana I.; Oliveira, Cláudia S.; Pintado, Manuela E.; Tavaria, Freni K.Introduction: The skin microbiome is a dynamic ecosystem vital for skin health, comprising bacteria like Staphylococcus spp. And Cutibacterium acnes, and fungi such as Candida and Malassezia spp. Dysbiosis, or microbial imbalance, can lead to conditions like acne and dermatitis. Current treatments, including anti-inflammatory drugs and antimicrobials, help manage dysbiosis but have limitations, such as microbiome disruption and antimicrobial resistance. Consequently, interest in natural alternatives,particularly essential oils (EOs), is increasing. Rich in bioactive terpenes and terpenoids, EOs target multiple cellular structures, reducing microbial adaptation and resistance. Flow cytometry, a powerful analytical tool, enables precise assessment of antimicrobial activity by distinguishing live and dead microorganisms using fluorescent staining. This study evaluates the antimicrobial effects of eucalyptus, lavender, and thyme EOs, offering insights into their potential as microbiome-friendly therapeutic agents. Methods: flow cytometry assay was used to assess the antimicrobial activity of eucalyptus, lavender, and thyme EOs against seven skinassociated microorganisms: methicillin-susceptible Staphylococcus aureus (MSSA), methicillin-resistant S. aureus (MRSA), Staphylococcus epidermidis (S. epidermidis), Cutibacterium acnes (C. acnes), Candida albicans (C. albicans), Candida tropicalis (C. tropicalis), and Malassezia furfur (M. furfur). Firstly, minimum inhibitory (MIC) and bactericidal (MBC) concentrations were determined. Then, to further explore EOs antimicrobial effects, microbial cells were exposed to MIC, ½MIC, and ¼MIC of each oil, followed by staining with propidium iodide (PI) and thiazole orange (TO). Flow cytometry was then used to assess viability, membrane integrity, and cell death. Additionally, fluorescence microscopy was performed on yeasts exposed to eucalyptus oil at ¼MIC, providing complementary validation of the flow cytometry findings. Results: The MIC and MBC values of the tested EOs ranged from 0.06% to 2.5% (v/v), with thyme EO showing the lowest values for all microorganisms, indicating its strongest antimicrobial activity. Among bacteria, S. epidermidis had the highest MIC/MBC values, suggesting greater resistance, while C. acnes had the lowest, indicating higher susceptibility. Among yeasts, C. albicans exhibited the highest values, whereas C. tropicalis and M. furfur were more susceptible. Flow cytometry confirmed these findings, validating thyme EO as the most effective, with the highest percentages of dead and injured cells. It also demonstrated that EOs antimicrobial activity is concentration-dependent. S. epidermidis had the highest percentage of live cells, reinforcing its resistance, while C. acnes had the lowest, confirming its susceptibility. C. albicans was more resistant than C. tropicalis. For M. furfur, fluorescence microscopy clarified an apparent lack of TO staining in flow cytometry, confirming viable but unstained cells. Conclusion: The selected EOs exhibited antimicrobial activity against all tested microorganisms. Thyme EO showed the strongest effect. Flow cytometry confirmed the MIC/MBC results, revealing that thyme EO induced the highest percentages of dead and injured cells at all tested concentrations. Among bacteria, S. epidermidis was the most resistant, while C. albicans was the most resistant yeast. For M. furfur, flow cytometry suggested an absence of live cells due to the lack of TO staining, even in untreated samples. However, fluorescence microscopy confirmed that M. furfur cells remained viable but did not stain green like Candida spp. This discrepancy likely results from the yeast’s lipid-rich membrane interfering with TO uptake, highlighting potential staining limitations. This work reinforces flow cytometry as a powerful tool to validate EO’s antimicrobial effects and support the potential of thyme, eucalyptus, and lavender EO’s as natural alternatives for managing skin dysbiosis while preserving microbiome balance.
- Assessing the antimicrobial activity of essential oils against skin microorganisms using flow cytometryPublication . Lopes, Ana I.; Oliveira, Cláudia S.; Pintado, Manuela E.; Tavaria, Freni K.The skin microbiome, composed of bacteria like Staphylococcus spp. and Cutibacterium acnes and fungi such as Candida spp. and Malasseziaspp., plays a key role in skin health (Byrd et al., 2018). Dysbiosis, or microbial imbalance, is linked to conditions like acne and dermatitis (Egert etal., 2017). While conventional treatments, such as anti-inflammatory drugs and antimicrobials, can help, they may disrupt the microbiome andpromote resistance (Sfriso et al., 2020).Natural alternatives like essential oils (EOs) are gaining attention due to their terpene-rich composition, which targets multiple microbial structuresand reduces resistance risk (Zuzarte et al., 2011). Flow cytometry offers a precise method to assess antimicrobial effects by distinguishing livefrom dead cells through fluorescent staining (Shapiro, 2003).
- Nutritional composition and health benefits of peas-a bibliometric researchPublication . Akin, Melekşen; Eyduran, Sadiye Peral; Mileṧevic, Jelena; Pavlovic, Suzana; Orahovac, Amil; Vasconcelos, Marta W.; Knez, MarijaPea (Pisum sativum L.) is a nutritious legume with health benefits, gaining attention as a functional food. Bibliometric studies use quantitative methods to assess research trends, gaps, and future directions. The main objective of this study was to provide a comprehensive overview of the fragmented literature on the nutritional profiles and health benefits of peas using a bibliometric approach. The analysis examined publications from 2013 to 2023, revealing trends in publication volume, author productivity, and international collaboration. Publications peaked in 2015, focusing on topics such as dietary fibers, carotenoids, phenolic compounds, and antinutrients affecting mineral bioavailability. Over the decade, the annual growth rate was 3.25%. The University of Saskatchewan produced the most influential research, with Warkentin TD as the most productive author. Canada and Poland had the highest number of publications, with the USA, China, and India following. Six major international co-authorship networks were identified, highlighting significant collaborations between countries. Key research themes included antioxidants, protein, fiber, and phytate in peas. This study provides a strong foundation for future integrated research, helping to better understand the potential of peas as a functional food and guiding more targeted studies to address current knowledge gaps across various disciplines.