Bangladesh Council of Scientific and Industrial Research

Zinc oxide nanoparticles (ZnO NPs) were synthesized through green-approach methods using aqueous solution of fallen Aegle marmelos leaf extract. The prepared NPs were characterized using different spectroscopy techniques including Fourier Transform Infrared (FTIR), Dynamic Light Scattering (DLS), X-ray Diffraction Patterns (XRD) and electron microscopy such as Field Emission Scanning Electron Microscopy (FESEM). XRD study confirmed the formation of crystalline hexagonal ZnO phase (wurtzite structure) with an average crystal size of 21.23 nm. FESEM analysis suggests the formation of 57.32 nm of ZnO NPs and the particles are almost spherical and moderately polydispersed. FTIR showed the vibration peaks for alkaloids, flavonoids and phenolic compounds which could act as both a reducing agent and a stabilizer for the prepared NPs. The high colloidal stability of the NPs is confirmed from the high ξ potential (-33.6 mV). The synthesized NPs showed concentration-dependent antioxidant activity with an IC₅₀ of 47.67 µg/mL, indicating strong but lower potency than ascorbic acid (12.39 µg/mL). The prepared NPs were utilized for the application of antibacterial activity and anti-diarrheal activity. The NPs exhibited higher antibacterial activity for S. aureus pathogen (ZOI, 18.2 ± 0.4) among the four identified different gram-positive and gram-negative strains, with maximum efficacy observed at higher concentrations (100 µg/mL) of NPs dose. The biosynthesized ZnO NPs were found to have excellent anti-diarrheal activity for both the 200 mg/kg and 400 mg/kg NPs doses. Overall, this study shows a sustainable waste-to-nanomaterial strategy that combines green synthesis with multifunctional biomedical potential.

This study explores the sustainable transformation of Nypa fruticans roots (NFR) into high-performance activated carbon (AC) through optimized physical and chemical activation, addressing both biomass waste management and the demand for eco-friendly adsorbents. Collected from Bangladesh's Sundarbans mangrove forest, NFR was processed via pyrolysis (600( degrees)C) and H3PO4 activation (1.0-2.0 impregnation ratios) to produce four AC variants (N1-N4). Comprehensive characterization revealed N3 as the standout material, exhibiting exceptional microporosity (BET surface area: 680 m(2)/g), high fixed carbon (51.2 %), and superior iodine adsorption (1050 mg/g, Langmuir q(max)). FTIR and XRD analyses correlated N3's performance with its graphitic C=C bonds (1600-1650 cm(-1)) and balanced oxygen groups, while FESEM confirmed a honeycomb pore structure. In contrast, N2's lower capacity (920 mg/g) was attributed to pore blockage from higher ash (12.5 %) and oxygen content (13 %). Iodine isotherm studies validated Langmuir monolayer dominance (R-2 > 0.98) and Freundlich heterogeneity (1/n = 0.58-0.65), with N3's optimal pore distribution making it ideal for gas purification, whereas N1/N4 (752-702 mg/g) suited water treatment. TGA highlighted N3's thermal stability, with lignin-derived carbonization above 400 C-degrees yielding 19.8 % ash. Economically, NFR's abundance and the method's scalability underscore its potential for low-cost, renewable AC production. This work not only advances mangrove biomass valorization but also provides a blueprint for tailoring AC properties via activation protocols, bridging ecological conservation with material science innovation. Future research should explore pilot-scale production and application-specific modifications to optimize real-world performance.

Pure ZnO and Ag-doped ZnO (0.5 %, 3 %, and 8.5 %) nanoparticles (NPs) were synthesized using a facile and eco-friendly route using Citrus sinensis (orange) peel extract as a reducing and stabilizing agent. Comprehensive structural, morphological, optical, thermal, antibacterial, and photocatalytic analyses were performed. The XRD analysis confirmed a hexagonal wurtzite phase, while the size-strain plot (SSP) model provided the most accurate crystallite size estimates (R-2 = 0.80-0.99): 37.41, 41.49, 28.67, and 24.24 nm for pure and Ag-doped ZnO (0.5 %, 3 %, 8.5 %), respectively. FESEM images revealed elongated ZnO NPs, while Ag doping resulted in distorted spheres with sizes varying around 40-70 nm. The EDX analysis confirmed the presence of the desired elements in the synthesized NPs. Ag incorporation induced a redshift in absorption and narrowed the bandgap from 3.19 to 3.09 eV. TG/DT analysis indicated enhanced thermal stability of ZnO with increasing Ag content. The presence of different functional groups was determined from the FT-IR spectra. Antibacterial tests showed that 3 % Ag-ZnO exhibited the strongest inhibition zones (12 mm for Escherichia coli, 16 mm for Staphylococcus aureus). Moreover, 3 % Ag-ZnO achieved the highest photocatalytic degradation efficiency-36.37 % for methylene blue (MB) and 88.48 % for methyl orange (MO) within 90 min-following pseudo-first-order kinetics with rate constants of 0.00471 and 0.02513 min(-)(1) , respectively. Excessive Ag loading (8.5 %) diminished photocatalytic activity compared to 3 % Ag-ZnO but still outperformed pristine ZnO.

The growing demand for safe, sustainable, and clean-label food preservation strategies has accelerated interest in plant-derived essential oils (EOs) as natural antimicrobial agents. These chemically complex mixtures exhibit broad-spectrum activity against foodborne pathogens and spoilage microorganisms through multitarget mechanisms, including membrane disruption, metabolic interference, oxidative stress induction, and modulation of quorum sensing and biofilm formation. However, their practical application remains constrained by compositional variability, physicochemical instability, matrix-dependent efficacy, and sensory limitations. Recent advances in multiomics technologies have shifted the understanding of EO-microbe interactions from descriptive observations to mechanistic, systems-level insights. Transcriptomic, proteomic, and metabolomic analyses reveal coordinated cellular responses, including stress adaptation, efflux activation, and metabolic reprogramming, providing a foundation for rational optimization of EO-based preservation strategies. In parallel, artificial intelligence (AI) and machine learning (ML) offer complementary tools for modeling complex interactions and predicting antimicrobial outcomes. However, their application remains limited by data heterogeneity, insufficient validation in real food systems, and challenges in interpretability. This review critically synthesized mechanistic, omics-driven, and AI-enabled approaches in EO-based food preservation, while addressing key translational barriers, including lack of standardization, regulatory complexity, and scalability. Integrating mechanistic biology with data-driven modeling provides a pathway toward more reliable and precision-oriented EO preservation systems aligned with sustainable food safety demands.

The growing demand for natural, clean-label, and sustainable food products has driven significant interest in essential oils (EOs) as promising alternatives to synthetic preservatives. EOs, derived from aromatic plants, exhibit potent antimicrobial, antioxidant, and antifungal activities, making them highly suitable for enhancing food safety and extending shelf life. This review provided a comprehensive and critical analysis of recent advancements in the application of EOs in food preservation, with a particular focus on their incorporation into active packaging, edible coatings, and smart delivery systems. Special attention is given to the underlying mechanisms of EO bioactivity, their chemical diversity, and the factors affecting their stability and efficacy in complex food matrices. The review also explores the synergistic effects of EO combinations, limitations related to sensory impact and volatility, and the emerging role of nanoencapsulation techniques in controlled release and targeted functionality. A novel dimension of this review lies in its integration of artificial intelligence (AI) technologies, which offer transformative potential in optimizing EO formulations, predicting sensory thresholds, and enabling adaptive release through smart packaging. Real-world case studies and commercial applications are discussed to bridge the gap between research and industrial practice. Finally, the review outlines critical research gaps, regulatory challenges, and future directions, emphasizing the need for interdisciplinary innovation to fully realize the potential of AI-enhanced EO systems. This work contributes a forward-looking framework for the development of intelligent, sustainable, and consumer-friendly food preservation strategies.