Continuously increasing energy demand and growing concern about energy resources has attracted much research in the field of clean and sustainable energy sources. In this context, zero-emission fuels are required for energy production to reduce the usage of fossil fuel resources. Here, we present the synthesis of Pd-Ag-decorated reduced graphene oxide (rGO) nanostructures using a green chemical approach with stevia extract for hydrogen production and antibacterial studies under light irradiation. Moreover, bimetallic nanostructures are potentially lime lighted due to their synergetic effect in both scientific and technical aspects. Structural characteristics such as crystal structure and morphological features of the synthesized nanostructures were analyzed using X-ray diffraction and transmission electron microscopy. Analysis of elemental composition and oxidation states was carried out by X-ray photoelectron spectroscopy. Optical characteristics of the biosynthesized nanostructures were obtained by UV-Vis absorption spectroscopy, and Fourier transform infrared spectroscopy was used to investigate possible functional groups that act as reducing and capping agents. The antimicrobial activity of the biosynthesized Pd-Ag-decorated rGO nanostructures was excellent, inactivating 96% of Escherichia coli cells during experiments over 150 min under visible light irradiation. Hence, these biosynthesized Pd-Ag-decorated rGO nanostructures can be utilized for alternative nanomaterial-based drug development in the future.
Multidrug resistant bacteria create a challenging situation for society to treat infections. Multidrug resistance (MDR) is the reason for biofilm bacteria to cause chronic infection. Plant-based nanoparticles could be an alternative solution as potential drug candidates against these MDR bacteria, as many plants are well known for their antimicrobial activity against pathogenic microorganisms. Spondias mombin is a traditional plant which has already been used for medicinal purposes as every part of this plant has been proven to have its own medicinal values. In this research, the S. mombin extract was used to synthesise AgNPs. The synthesized AgNPs were characterized and further tested for their antibacterial, reactive oxygen species and cytotoxicity properties. The characterization results showed the synthesized AgNPs to be between 8 to 50 nm with -11.52 of zeta potential value. The existence of the silver element in the AgNPs was confirmed with the peaks obtained in the EDX spectrometry. Significant antibacterial activity was observed against selected biofilm-forming pathogenic bacteria. The cytotoxicity study with A. salina revealed the LC50 of synthesized AgNPs was at 0.81 mg/mL. Based on the ROS quantification, it was suggested that the ROS production, due to the interaction of AgNP with different bacterial cells, causes structural changes of the cell. This proves that the synthesized AgNPs could be an effective drug against multidrug resistant bacteria.
Alocasia longiloba, locally known as 'Keladi Candik', has been used traditionally to treat wounds, furuncle and joint inflammations. A. longiloba can be a new source of herbal medicine against hyperuricemia by inhibiting the activity of xanthine oxidase enzyme, the enzyme which is responsible for the development of hyperuricemia in human. Existing xanthine oxidase inhibitors (XOI drugs) show several side effects on gout patients. Therefore, an alternative herbal medicine from plants, with high therapeutic property and free of side effects, are greatly needed. This study was conducted to evaluate XO inhibitory activity, chemical composition, antioxidant activity and GC-MS profile of A. longiloba. Our results showed that ethanolic petiole extract exhibited the highest XO inhibitory activity (70.40 ± 0.05%) with IC50 value of 42.71 μg/mL, followed by ethanolic fruit extracts (61.44 ± 1.24%) with the IC50 value of 51.32 μg/mL. In a parallel study, the phytochemical analysis showed the presence of alkaloid, flavonoid, terpenoids, glycoside and saponin in petiole and fruit extracts, as well as higher total phenolic and flavonoid contents and strong scavenging activity on DPPH and ABTS antioxidant assay. The GC-MS analysis of fruit and petiole extracts revealed the presence of various compounds belonging to different chemical nature, among them are limonen-6-ol, α-DGlucopyranoside, paromomycin, aziridine, phenol, Heptatriacotanol, Phen-1,2,3-dimethyl and Betulin found in ethanolic fruit extract, and Phen-1,4-diol,2,3-dimethyl-, 1-Ethynyl-3,trans(1,1-dimethylethyl), Phenol,2,6-dimethoxy-4-(2-propenyl)- and 7-Methyl-Z-tetradecen-1-olacetate found in ethanolic petiole extract. Some compounds were documented as potent anti-inflammatory and arthritis related diseases by other researchers. In this study, the efficiency of solvents to extract bioactives was found to be ethanol > water, methanol > hexane > chloroform. Together, our results suggest the prospective utilization of fruit and petiole of A. longiloba to inhibit the activity of XO enzyme.
Due to modernization and the scarcity of fossil fuel resources, energy demand is continuously increasing. In this regard, it is essential and necessary to create a renewable energy source that can meet future energy demands. Recently, the production of H2 by water splitting and removing pollutants from the water has been essential for issues of energy and environmental demands. Herein, g-C3N4 and Ag-g-C3N4 composite structures have been successfully fabricated by the ultrasonication method. The physio/photochemical properties of prepared g-C3N4 and Ag-g-C3N4 were examined with different analytical techniques such as FTIR, XRD, UV-DRS, SEM, TEM, PL, and XPS analyses. The silver quantum dots (QDS) anchored to g-C3N4 structures performed the profound photocatalytic activities of H2 production, dye degradation, and antimicrobial activity under visible-light irradiation. The Ag/g-C3N4 composite with an Ag loading of 0.02 mole has an optimum photoactivity at 335.40 μmol g-1 h-1, which is superior to other Ag loading g-C3N4 composites. The synthesized Ag/g-C3N4 nanoparticles showed potential microbial inhibition activity during the preliminary screening, and the inhibition zones were comparable to the commercial antibiotic chloramphenicol. The loading of Ag into g-C3N4 paves the suppression, recombination and transfer of photo-generated electron-hole pairs, leading to the enhancement of hydrogen production, the diminishment of pollutants in water under visible light irradiation, and antimicrobial activity against multidrug-resistant pathogens.