Evaluation of phytoactive contents and antibacterial activities of green synthesised cerium oxide nanoparticles using Melastoma sp. leaf extract as the capping agent.

Simple and green methods of developing nanoparticles (NPs) have attracted the attention of researchers. Literature on utilising leaf extract to prepare cerium oxide (CeO2 NPs) is scarce. The present study synthesised leaf-mediated-CeO2 NPs to produce nanopowders of controllable sizes for further applications. The study is the first to report the optimised parameters (pH 7, 5 g/150 mL concentration of the leaf extract, and 3 h of reaction time) of procuring CeO2 NPs using Melastoma sp. leaf extract as the capping agent with excellent properties. The absorbance of the NPs suspension obtained in this study was recorded at approximately 252 nm with Ultraviolet-Visible (UV-Vis) Spectroscopy. Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), and Transmission Electron Microscopy (TEM) were also utilised to characterise and confirm the CeO2 NPs prepared. The XRD spectra documented the purity of the NPs at specific diffraction patterns, while TEM revealed the spherical form of the NPs with a particle size of 16 nm. The formation of CeO2 NPs has been confirmed from the FTIR spectra procured, which exhibited a Ce-O peak at 555 nm. Phytochemical screening test and FT-IR analysis of leaf extract revealed the existence of flavonoids, terpenoids, sugars, saponins, quinones, and glycosides. The NPs suspensions of varying concentrations (control, 50, 100, 150, 200, and 250 µg/mL) were prepared and employed for evaluations against Gram-positive and -negative bacteria. Resultantly, CeO2 NPs demonstrated antibacterial activities against both bacteria types. The highest antibacterial activities were recorded against E. coli and K. pneumonia at 1.83 ± 0.137 and 1.83 ± 0.14 mm maximum inhibition zones, respectively, at 250 mg/uL of the NPs.

Application of response surface methodology in enzymatic synthesis: a review.

There are very chemical reactions with very slow rates which can be catalyzed by enzymes. These biocatalysts need to moderate conditions for their catalytic activity and are stable in low temperature (between 15-50°C), average pH (5-10) and aqueous media. One of important things in enzymatic synthesis which has been recently noticed is the yield of reactions. Nowadays wide application of response surface methodology (RSM) was observed in organic chemistry. In one-variable-at-a-time technique only one parameter is changed and other parameters are kept at a constant level. It does not study the interactive effects among the variables, and does not illustrate the complete effects of the parameters on the process. Increasing the yield of product without increase in casts is carried out by modeling and optimization of reaction variables through statistical techniques such as RSM. In this paper, we reviewed some articles that used the RSM for optimization in the enzymatic synthesis.

Synthesis and characterization of lawsone-lntercalated Zn-Al-layered double hydroxides.

A drug-inorganic nanostructured material involving pharmaceutically active compound lawsone intercalated Zn-Al layered double hydroxides (Law-LDHs) with Zn/AI = 4 has been assembled by co-precipitation and ion exchange methods. Powder X-ray diffraction (XRD) and Fourier transform infrared spectra (FTIR) analysis indicate a successful intercalation of lawsone between the layers of layered double hydroxides. It suggests that layered double hydroxides may have application as the basis of a drug delivery system.