Nittiya Suwannasom

Human skin is continuously exposed to microbial invasion and oxidative stress, highlighting the need for safe and effective natural skin-protective agents. This study aims to investigate the antibacterial, antioxidant, and anti-tyrosinase activities of methanolic leaf extracts of Syzygium nervosum collected from Chiang Mai (SNLM-CM) and Phayao (SNLM-PY), Thailand. LC–QTOF–MS analysis revealed distinct phytochemical profiles between the extracts, suggesting that geographical origin influenced their biological activities. Antibacterial activity against Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, and Escherichia coli was evaluated, together with studies of bacterial membrane integrity. Antioxidant capacity was assessed using ABTS, DPPH, FRAP, and ORAC assays, while anti-tyrosinase activity and cytotoxicity toward normal human dermal fibroblasts (NHDF) were determined by MTT assay. Both extracts exhibited potent antibacterial activity, particularly against Gram-positive bacteria (S. aureus and S. epidermidis) likely through membrane disruption, as evidenced by propidium iodide uptake, intracellular DNA and protein leakage, and scanning electron microscopy observations. SNLM-CM showed stronger antioxidant activity, whereas SNLM-PY demonstrated greater anti-tyrosinase activity. The extracts maintained high NHDF viability at concentrations below 100 µg/mL and retained antibacterial efficacy when incorporated into a cleansing gel formulation. Overall, S. nervosum leaf extracts exhibit promising antibacterial, antioxidant, and anti-tyrosinase activities, warranting further investigation to optimize their safety and efficacy for dermatological and cosmetic use.

Computer devices in university settings are frequently shared and repeatedly handled, making them potential reservoirs for pathogenic bacteria. This study aimed to investigate the prevalence, virulence determinants, and antimicrobial resistance profiles of Staphylococcus aureus and Escherichia coli isolated from computer devices used by staff and students at a university in Northern Thailand. A total of 400 computer devices were sampled, with each device defined as a single sampling unit comprising both the keyboard and computer mouse. Bacterial identification was performed using PCR, while staphylococcal enterotoxin (se) genes and diarrheagenic E. coli (DEC)-associated virulence genes were detected by PCR. Antimicrobial susceptibility was assessed using the disk diffusion method. Overall, 74 (18.5%) S. aureus isolates and 6 (1.5%) E. coli isolates were recovered. The highest prevalence of S. aureus was observed among personal-use student computer devices (29%; p < 0.001), whereas E. coli was most frequently detected on public-use staff computer devices (4%). Among S. aureus isolates, 24.3% (18/74) carried at least one se gene, with sec being the most prevalent (13.5%). Half of the E. coli isolates harbored the astA gene. Low resistance rates (S. aureus; however, four isolates (5.4%) were classified as MRSA, three of which exhibited multidrug resistance. All E. coli isolates were resistant to ampicillin, and 50% displayed multidrug-resistant phenotypes. These findings suggest that computer devices can act as occasional reservoirs of potentially pathogenic and antimicrobial-resistant bacteria in university environments.

Background and Aim: Houseflies (Musca domestica) are recognized mechanical vectors of foodborne pathogens and antimicrobial-resistant bacteria, particularly in environments with intensive food-handling. Their role in disseminating virulent and multidrug-resistant (MDR) Escherichia coli at the food–environment–human interface remains underexplored in Northern Thailand. This study aimed to determine the prevalence, phylogenetic distribution, virulence gene carriage, antimicrobial resistance profiles, and resistance determinants of E. coli isolated from houseflies collected at food markets in Phayao Province. Materials and Methods: A cross-sectional surveillance study was conducted between June and November 2023 in Muang District, Phayao Province. A total of 350 houseflies were collected from meat, vegetable, and cooked-food markets using sticky traps. E. coli isolates were identified by culture and polymerase chain reaction (PCR) targeting the uidA gene. Phylogenetic grouping was performed using chuA, yjaA, and TSPE4.C2. Virulence genes associated with diarrheagenic E. coli were detected by PCR. Antimicrobial susceptibility testing was conducted using the disc diffusion method against 12 antibiotics representing eight antimicrobial classes. Multidrug resistance was defined as resistance to three or more antimicrobial classes. Resistance-associated genes were screened by PCR. Associations were analyzed using the chi-square test. Results: Overall, 106 E. coli isolates (30.3%) were recovered, with the highest prevalence in meat markets (39.5%) (p < 0.0001). Phylogroup A predominated (49.1%), followed by D (19.8%), B1 (18.9%), and B2 (12.3%). Virulence genes were detected in 69.8% of isolates, with bfpA being the most prevalent (26.4%). Universal resistance to penicillin G and erythromycin was observed, while high resistance rates were noted for ampicillin (66.0%) and tetracycline (35.8%). MDR was identified in 46.2% of isolates and was significantly more common in meat markets (p = 0.0225). The highest MDR prevalence occurred in phylogroup D (57.1%). The most frequently detected resistance genes were blaSHV, ereA, and tetA. Conclusion: Houseflies from food markets in Northern Thailand harbor virulent and MDR E. coli, highlighting their role as environmental sentinels and potential disseminators of antimicrobial resistance. These findings underscore the need for improved market hygiene and incorporation of insect vectors into One Health–based antimicrobial resistance surveillance strategies. Keywords: antimicrobial resistance, Escherichia coli, food markets, houseflies, multidrug resistance, Northern Thailand, One Health, virulence genes.

Glioblastoma (GBM) is the most aggressive and treatment-resistant primary brain tumor in adults. Despite current multimodal therapies, including surgery, radiation, and temozolomide chemotherapy, patient outcomes remain poor. Enhancing tumor radiosensitivity through biocompatible nanomaterials could provide a promising integrative strategy for improving therapeutic effectiveness. This study aims to evaluate the potential of bovine serum albumin-coated copper oxide nanoparticles (BSA@CuO-NPs) to enhance radiosensitivity in U87-MG cells under clinically relevant X-ray irradiation. In brief, BSA@CuO-NPs were synthesized via carbodiimide crosslinking and characterized by DLS, SEM, and zeta potential analysis. U87-MG cells were treated with BSA@CuO-NPs alone or in combination with X-ray irradiation (2 Gy). Cytotoxicity was assessed using the MTT assay, while radiosensitization was evaluated through clonogenic survival analysis. Apoptosis induction and DNA damage were analyzed via Annexin V staining and γ-H2AX immunofluorescence, respectively. The results revealed that BSA@CuO-NPs showed good colloidal stability and biocompatibility compared with uncoated CuO-NPs. When combined with irradiation, BSA@CuO-NPs significantly decreased clonogenic survival (p < 0.05) and increased apoptotic cell death compared to irradiation alone. Immunofluorescence demonstrated increased γ-H2AX focus formation, indicating higher DNA double-strand breaks in the combination group. In conclusion, BSA@CuO-NPs enhance the effects of ionizing radiation by increasing DNA damage and apoptosis in U87-MG cells, indicating their potential as combined radiosensitizers. These results support further research into albumin-coated metal oxide nanoparticles as adjuncts to standard radiotherapy for the management of GBM. One challenge in this context is the effective delivery of nanoparticles to GBM. However, the stability of BSA@CuO-NPs in physiological solutions could help overcome this obstacle.

Northern Thai culture offers a rich variety of traditional fermented foods beneficial for gastrointestinal health. In this study, we characterized lactic acid bacteria (LAB) from various indigenous fermented foods as potential probiotic candidates and determined their properties for application in commercial synbiotic formulation. Five isolates demonstrating high tolerance to low pH (2.0) and 0.3% bile salts were collected and characterized. These included three strains of Lactiplantibacillus plantarum isolated from nham (NB1, NP2, and NP11) and two strains of Limosilactobacillus fermentum isolated from pla-som (PS4 and PS7). All the selected LAB isolates exhibited γ-hemolytic activity, strong antimicrobial activity, and high resistance to gastric and duodenal digestion conditions. Among the LAB isolates, L. plantarum NB1 demonstrated the highest capacity for adhesion to Caco-2 cells, auto-aggregation, and antioxidant activity, differing significantly (p < 0.05) from the other isolates. Furthermore, the NB1 strain exhibited preferential growth in the presence of commercial prebiotics (fructooligosaccharide, lactose, and inulin) and good survival after lyophilization, which is a desirable characteristic for a powdered ingredient. Therefore, the NB1 strain is a suitable probiotic candidate for applications in synbiotic formulation or as a functional food ingredient.

Curcumin (CUR), a polyphenolic compound, shows promising biological properties, particularly antioxidant activity. However, its medical applications are limited due to its low water solubility, bioavailability, and pH-instability. CUR-loaded albumin microparticles (CUR-HSA-MPs) of submicron size in the range of 800 to 900 nm and a zeta potential of −15 mV were prepared. The CUR loading efficiency was up to 65%. A maximum release of 37% of the encapsulated CUR was observed within 6 h when the CUR-HSA-MPs were dispersed in 50% ethanol in PBS at pH 7, while in RPMI 1640 medium the release was 7%. This demonstrates a sustainable release. The in vitro cytotoxicity of CUR-HSA-MPs showed promising anticancer potential against human hepatocellular carcinoma (Huh-7) and human breast adenocarcinoma (MCF-7) cell lines, although this effect was less pronounced in human dermal fibroblasts (HDFB) and human cholangiocyte (MMN) cell lines. Confocal microscopy was used to confirm the uptake of CUR-HSA-MPs by cancer cells. Our studies revealed that HSA-MPs are potentially promising vehicles for increasing the solubility and bioavailability of CUR.

Curcumin (CUR), a polyphenolic compound, shows promising biological properties, particularly antioxidant activity. However, its medical applications are limited due to its low water solubility, bioavailability, and pH-instability. CUR-loaded albumin microparticles (CUR-HSA-MPs) of submicron size in the range of 800 to 900 nm and a zeta-potential of -15 mV were prepared. The CUR loading efficiency was up to 65%. A maximum release of 36% of the encapsulated CUR in 50% ethanol in PBS, pH 7, was observed within 6 h, demonstrating sustainable release. The in vitro cytotoxicity of CUR-HSA-MPs showed promising anticancer potential against human hepatocellular carcinoma (Huh-7) and human breast adenocarcinoma (MCF-7) cell lines, although this effect was less pronounced in human dermal fibroblasts (HDFB) and human cholangiocyte (MMN) cell lines. Confocal microscopy was used to confirm the uptake of CUR-HSA-MPs by cancer cells. Our studies revealed that HSA-MPs are potentially promising vehicles for increasing the solubility and bioavailability of CUR.