Antibacterial, bacteriolytic, and antibiofilm activities of the essential oil of temu giring (Curcuma heyneana Val.) against foodborne pathogens.

Foodborne pathogens may cause foodborne illness, which is among the major health problems worldwide. Since the therapeutic options for the treatment of the disease are becoming limited as a result of antibacterial resistance, there is an increasing interest to search for new alternatives of antibacterial. Bioactive essential oils from Curcuma sp become potential sources of novel antibacterial substances. The antibacterial activity of Curcuma heyneana essential oil (CHEO) was evaluated against Escherichia coli, Salmonella typhi, Shigella sonnei, and Bacillus cereus. The principal constituents of CHEO are ar-turmerone, ß-turmerone, α-zingiberene, α-terpinolene, 1,8-cineole, and camphor. CHEO exhibited the strongest antibacterial activity against E. coli with a MIC of 3.9 µg/mL, which is comparable to that of tetracycline. The combination of CHEO (0.97 µg/mL) and tetracycline (0.48 µg/mL) produced a synergistic effect with a FICI of 0.37. Time-kill assay confirmed that CHEO enhanced the activity of tetracycline. The mixture disrupted membrane permeability of E. coli and induced cell death. CHEO at MIC of 3.9 and 6.8 µg/mL significantly reduced the formation of biofilm in E. coli. The findings suggest that CHEO has the potential to be an alternative source of antibacterial agents against foodborne pathogens, particularly E. coli.

Culturable endophytic fungal assemblages from Styrax sumatrana and Stryax benzoin and their potential as antifungal, antioxidant, and alpha-glucosidase inhibitory resources.

Benzoin resin, produced by the native Indonesian trees Styrax sumatrana and Styrax benzoin, has been incorporated into medical practices to treat wounds, erythema, and many other conditions for centuries. Endophytic fungi that reside within medicinal plants have antimicrobial, antioxidant, and α-glucosidase inhibitory capacities, contributing to plant health and derivative products. In this study, we determined the antifungal, antioxidant, and α-glucosidase inhibitory capacities of endophytic fungal isolates from three different tissues (leaves, bark, and stems) of S. sumatrana and S. benzoin trees. The genera of fungal isolates were determined by phylogenetic analysis of internal transcribed spacer sequences. A total of 58 fungal isolates were classified into 15 different fungal genera from eight taxonomic orders-Hypocreales, Botryosphaeriales, Glomerellales, Diaphortales, Pleosporales, Eurotiales, Xylariales, and Mucorales-with a pattern of host species specificity. Among these isolates, Trichoderma sp. 6407 consistently exhibited high inhibition of the growth of plant pathogens Fusarium sp., Trichoderma viride, and Aspergillus niger. With respect to antioxidant activity, Phyllosticta sp. 6454 consistently showed 2,2-diphenyl-1-picrylhydrazyl inhibition (37.59 ± 0.05%), 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid)-based antioxidant activity (25.04 ± 0.27 mgTE/g), and α-glucosidase inhibitory activity (52.15 ± 10.08%). Neopestalotiopsis sp. 6431 was notably potent in 2,2-diphenyl-1-picrylhydrazyl inhibition (49.65 ± 0.80%), ferric reducing antioxidant power-based antioxidant activity (197.49 ± 8.65 mgTE/g), and α-glucosidase inhibitory activity (52.88 ± 4.93%). This study revealed that Trichoderma sp. 6407, Phyllosticta sp. 6454, and Neopestalotiopsis sp. 6431 exhibited antifungal, antioxidant, and α-glucosidase inhibitory activities.

Optimized antibody immobilization on natural silica-based nanostructures for the selective detection of E. coli.

This study reports for the first time the surface modification of fluorescent nanoparticles derived from geothermal silica precipitate with Escherichia coli (E. coli) antibody. The immobilization of biomolecules on the inorganic surface has been carried out using two different pathways, namely the silanization and hydrosilylation reactions. The former applied (3-aminopropyl)triethoxysilane (APTES) as the crosslinker, while the latter used N-hydroxysuccinimide coupled with N-ethyl-N'-(3-dimethyl aminopropyl) carbodiimide hydrochloride (EDC/NHS). Fourier transform infrared (FTIR) spectroscopy, field emission scanning electron microscopy with energy dispersive X-ray spectroscopy (FESEM-EDX), and fluorescence spectroscopy were used to confirm the chemical, physical, and optical properties of the surface-modified fluorescent silica nanoparticles (FSNPs). Based on the results of the FTIR, fluorescence spectroscopy and stability tests, the modified FSNPs with EDC/NHS with a ratio of 4 : 1 were proven to provide the optimum results for further conjugation with antibodies, affording the FSNP-Ab2 sample. The FSNP-Ab2 sample was further tested as a nanoplatform for the fluorescence-quenching detection of E. coli, which provided a linear range of 102 to 107 CFU mL-1 for E. coli with a limit of detection (LoD) of 1.6 × 102 CFU mL-1. The selectivity of the biosensor was observed to be excellent for E. coli compared to that for P. aeruginosa and S. typhimurium, with reductions in the maximum fluorescence intensity at 588 nm of 89.22%, 26.23%, and 54.06%, respectively. The inorganic nanostructure-biomolecule conjugation with optimized coupling agents showed promising analytical performance as a selective nanoplatform for detecting E. coli bacteria.

Magnetic Graphene-Based Nanosheets with Pluronic F127-Chitosan Biopolymers Encapsulated α-Mangosteen Drugs for Breast Cancer Cells Therapy.

In this study, multifunctional chitosan-pluronic F127 with magnetic reduced graphene oxide (MRGO) nanocomposites were developed through the immobilization of chitosan and an amphiphilic polymer (pluronic F127) onto the MRGO. Physicochemical characterizations and in-vitro cytotoxicity of nanocomposites were investigated through field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, particle size analysis, vibrating sample magnetometer, Raman spectroscopy and resazurin-based in-vitro cytotoxicity assay. FESEM observation shows that the magnetic nanoparticles could tethered on the surface of MRGO, promoting the magnetic properties of the nanocomposites. FTIR identification analysis revealed that the chitosan/pluronic F127 were successfully immobilized on the surface of MRGO. Furthermore, α-mangosteen, as a model of natural drug compound, was successfully encapsulated onto the chitosan/pluronic F127@MRGO nanocomposites. According to in-vitro cytotoxicity assay, α-mangosteen-loaded chitosan/pluronic F127@MRGO nanocomposites could significantly reduce the proliferation of human breast cancer (MFC-7) cells. Eventually, it would be anticipated that the novel α-mangosteen-loaded chitosan/pluronic F127@MRGO nanocomposites could be promoted as a new potential material for magnetically targeting and killing cancer cells.

A synergy interaction of artocarpin and tetracycline against Pseudomonas aeruginosa and its mechanism of action on membrane permeability.

The emergence of antibacterial resistance has significantly increased. Pseudomonas aeruginosa is associated with nosocomial infection and difficult to control. Artocarpin, a flavonoid from Artocarpus heterophyllus Lam. exhibits several pharmacological properties including antibacterial. The study was performed to evaluate interaction between artocarpin and antibiotics including tetracycline against P. aeruginosa. Its mechanism of action on membrane permeability was also investigated. Broth microdilution was conducted for the susceptibility assay. The interaction of artocarpin and antibiotics was evaluated using checkerboard method, the effect on alteration of membrane cell was investigated using bacteriolysis and the released of 260 nm materials. Artocarpin showed moderate to weak activity against the Gram-negative bacteria including P. aeruginosa with MIC values in the range of 31.25-250 µg/mL. A synergistic effect against P. aeruginosa was produced by the combination of artocarpin (31.25 µg/mL) and tetracycline (1.95 µg/mL) with FICI of 0.37. The time-killing assay showed that artocarpin enhance the antibacterial activity of tetracycline against P. aeruginosa by completely inhibiting the bacterial growth. Additionally, the mixture of artocarpin (31.25 µg/mL) and tetracycline (1.95 µg/mL) disrupted membrane permeability and lead to cell death. These results proposed that the combination of artocarpin and tetracycline may be used to overcome P. aeruginosa infection.

An experimental design approach for the optimization of scopoletin extraction from Morinda citrifolia L. using accelerated solvent extraction.

Scopoletin is regarded as a major constituent of noni (Morinda citrifolia L), which contributes to the antioxidative, anti-inflammatory, immunomodulatory, and hepatoprotective properties in noni. It is also suggested as a marker for identification and quality control of noni and its derivative products. With the increasing interest in noni due to its health benefits and therapeutic effects, it is important to establish a reliable extraction and analysis method to determine scopoletin content in noni samples. The present study proposes the use of accelerated solvent extraction (ASE) to extract scopoletin from noni, followed by detection using HPLC-DAD for rapid identification and quantification of scopoletin. The optimum operating conditions of ASE were investigated using response surface methodology (RSM), using a three factors central composite design. It was found that the optimum scopoletin yield was achieved by performing the extraction at an elevated temperature of 60 °C for 12 min, using ethanol as extraction solvent with solid to solvent ratio of 1:30 (w/v). The analytical method validation was carried out under optimum conditions. The results indicate that the proposed ASE-HPLC-DAD method was adequately sensitive for the quantification of scopoletin in extracts with limit of detection of 0.17 µg/g. The presented method also exhibits excellent linearity from 0.54 to 120.10 µg/g with R2 0.9995, high precision with RSD lower than 2% for intra-day and inter-day replication, and good recovery (99.88%). The established method was also successfully applied for scopoletin determination in noni product samples. The developed method provides a rapid and reliable method for the identification and quantification of scopoletin in noni samples that is suitable for routine procedures.