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Abstract Biofabrication of gold nanoparticles (AuNPs) using the aromatic essential oils is highlighted due to its simple, economical, low toxicity, and eco-friendly nature. Essential oil of Cymbopogon flexuosus (CF), an economically valuable medicinal plant, exhibits anti-inflammatory, anti-tumor, antioxidant, and antimicrobial activities. For the first time, this research accounts for the biosynthesis, physicochemical, photocatalytic, antifungal, antibacterial properties of biogenic AuNPs, fabricated using CF essential oil collected from different altitudes (S1-Palampur, S2-Haryana, S3-Dehradun). The altitudinal disparity in the phytochemical composition of essential oils is highlighted. The average crystallite size ranged from 10 to 32 nm and was influenced by CF samples used in the synthesis. The spectroscopic outcomes revealed the involvement of bioactive reagents from CF essential oil in the fabrication and stabilization of AuNPs. The fabricated AuNPs exhibited excellent antimicrobial activities against all tested strains (Staphyloccucs aureus, Escherichia coli, Fusarium oxysporum), showing their efficacy as an antimicrobial agent to treat infectious diseases. Moreover, AuNPs exhibited excellent photocatalytic efficacy of around 91.8% for the degradation of methylene blue under exposure of direct sunlight for 3 h without the assistance of an external reducing agent. The outcomes highlight a potential economic and environmentally friendly strategy to fabricate biogenic AuNPs for diversified industrial applications where antimicrobial and photocatalytic efficacies are the key requirements.

Abstract Emergent application of antimicrobial strategies as symptomatic treatment in coronavirus disease (COVID-19) and linkage of severe acute respiratory syndrome coronavirus2 with microbial infections, has created colossal demand for antimicrobials. For the first time, this communication explore the physicochemical, antifungal, antibacterial, and photocatalytic properties of biogenic magnesium nanoparticles (MgNPs), synthesized using essential oil of Cymbopogon flexuosus's as an efficient multifunctional reducing and stabilizing/capping reagent. It is observed that MgNPs (ranging in size: 8–16 nm) of varying phytochemical compositions (MgS1, MgS2, MgS3) exhibited various useful physicochemical, antimicrobial, and photocatalytic properties. FTIR outcomes highlight the functional biomolecules-assisted reduction of Mg from Mg+ to Mg0. Among all, MgS3-Nps owing to the smallest particle size exhibited superior photocatalytic efficacy (91.2%) for the methylene blue degradation upon direct exposure to the sunlight for 3 h without using any reducing agents. Fabricated MgNPs also exhibited excellent antifungal (against Fusarium oxysporum) and antibacterial (versus Staphylococcus aureus and Escherichia coli) efficacies compared to state-of-the-art antimicrobial agents deployed for the treatment of infectious diseases. Based on this investigated greener approach, imperative from economic and environmental viewpoint, such essential oil based-MgNPs can be a potential nanosystem for various industrial applications where photocatalytic, and biomedical attributes are the key requirements.

Abstract Amid ongoing devastation due to Serve-Acute-Respiratory-Coronavirus2 (SARS-CoV-2), the global spatial and temporal variation in the pandemic spread has strongly anticipated the requirement of designing area-specific preventive strategies based on geographic and meteorological state-of-affairs. Epidemiological and regression models have strongly projected particulate matter (PM) as leading environmental-risk factor for the COVID-19 outbreak. Understanding the role of secondary environmental-factors like ammonia (NH3) and relative humidity (RH), latency of missing data structuring, monotonous correlation remains obstacles to scheme conclusive outcomes. We mapped hotspots of airborne PM2.5, PM10, NH3, and RH concentrations, and COVID-19 cases and mortalities for January, 2021-July,2021 from combined data of 17 ground-monitoring stations across Delhi. Spearmen and Pearson coefficient correlation show strong association (p-value 0.60) and PM10 (r > 0.40), respectively. Interestingly, the COVID-19 spread shows significant dependence on RH (r > 0.5) and NH3 (r = 0.4), anticipating their potential role in SARS-CoV-2 outbreak. We found systematic lockdown as a successful measure in combatting SARS-CoV-2 outbreak. These outcomes strongly demonstrate regional and temporal differences in COVID-19 severity with environmental-risk factors. The study lays the groundwork for designing and implementing regulatory strategies, and proper urban and transportation planning based on area-specific environmental conditions to control future infectious public health emergencies.