In recent decades focus of research has been toward an alternative antibacterial agent because of growing bacterial resistance and side effects of antibacterial agents. In the current study, the antibacterial activity of gold nanoparticles has been evaluated on selected human pathogens. In this study, we used panchagavya (PG) to synthesize gold nanoparticles, and the resulting nanoparticles (PG-AuNPs) were characterized by several spectroscopic techniques. In addition, antibacterial activity of PG-AuNPs against Escherichia coli, Bacillus subtilis, and Klebsiella pneumoniae were studied by well diffusion method. The synthesis of AuNPs was affirmed by a colour change, which was further validated by UV-vis spectra with a maximum absorption peak at 527 nm. Bandgap energy was calculated as 2.13 eV by Tauc method from the UV result. The presence of amino acids and proteins in PG was responsible for the conversion of gold ions to AuNPs, according to FTIR analysis. (111), (200), (220), and (311) crystallographic planes were observed by XRD; further crystalline nature was validated by SAED analysis. The size and zeta value were found to be 53.29 nm and -9.8 mV respectively. Spherical shaped nanoparticles and elemental structure of PG-AuNPs were confirmed by HRTEM and EDS analysis. The antibacterial activity of PG-AuNPs showed the maximum and minimum zone of inhibition against K. pneumoniae (17.12 ± 0.14 mm) and B. subtilis (11.42 ± 0.58 mm). Antibacterial activity of PG-AuNPs was found to be strong against gram negative bacteria and moderate against gram positive bacteria. Based on the result, it was concluded that PG-AuNPs could be used to combat antibiotic drug resistance. Besides, in vitro and in vivo toxicity studies of PG-AuNPs should be conducted.

Jatropha integerrima Jacq. flower extract was used for the synthesis of silver nanoparticles in the current study. Various spectroscopic analyses were used to characterize the synthesized nanoparticles (JIF-AgNPs). The antibacterial efficacy of JIF-AgNPs was studied by well diffusion and microdilution techniques. In addition, the impact of JIF-AgNPs on free radicals was evaluated. On the ultraviolet–visible spectrum, the nanoparticles exhibit the highest absorbance at 422 nm. Based on the Fourier transform infrared spectrum, phenols and amino acids were involved in capping the JIF-AgNPs. Crystalline sphere-shaped nanoparticles with an average size of 50.07 nm and zeta potential of −19.0 mV were confirmed by X-ray diffraction, transmission electron microscopy, and dynamic light scattering analysis respectively. The JIF-AgNPs exhibit the highest and lowest growth inhibitory activity towards E. coli and B. subtilis. The minimal inhibitory concentration of JIF-AgNPs against E. coli, K. pneumoniae, S. aureus, and B. subtilis were 2.5, 5.0, 5.0, and 7.5 μg/mL, respectively. The JIF-AgNPs exhibited significant radical scavenging activities against DPPH (IC₅₀-32.5 ± 0.06 µg/mL), hydroxyl (IC₅₀-25 ± 0.09 µg/mL), Superoxide (IC₅₀-42.5 ± 0.13 µg/mL), and ABTs (IC₅₀-33.5 ± 0.15 µg/mL). Thus, synthesized nanoparticles were a good alternative to develop an antibacterial and antioxidant agent.

Alstonia scholaris is one of the most important medicinal plants and herein, we present the synthesis of zinc oxide nanoparticles using the bark extract of Alstonia scholaris, and evaluation of their antimicrobial efficacy. Stable ZnO nanoparticles were formed by treating 90 mL of 1 mM zinc nitrate aqueous solution with 10 mL of 10% bark extract. The formation of Alstonia scholaris bark extract mediated zinc oxide nanoparticles was confirmed by UV-visible spectroscopic analysis and recorded the localized surface plasmon resonance (LSPR) at 430 nm. Fourier transform infrared spectroscopic (FT-IR) analysis revealed that primary and secondary amine groups in combination with the proteins present in the bark extract is responsible for the reduction and stabilization of the ZnONPs. The crystalline phase of the nanocrystals was determined by XRD analysis and morphology was studied using transmission electron microscopy (TEM). The hydrodynamic diameter (26.2 nm) and a positive zeta potential (43.0 mV) were measured using the dynamic light scattering technique. The antimicrobial activity of Alstonia scholaris ZnONPs was evaluated (in-vitro) using disc diffusion method against fungi, Gram-negative and Gram-positive bacteria which were isolated from the biofilm formed in drinking water PVC pipelines. The results obtained suggested that ZnO nanoparticles exhibit a good anti-fungal activity than bactericidal effect towards all pathogens tested in in-vitro disc diffusion method (170 ppm, 100 ppm and 50 ppm). Further, the toxicity of biosynthesized ZnONPs was tested against Alstonia scholaris to evaluate the cytotoxic effect that displayed LC50 value of 95% confidence intervals.

Increased urbanization and increase in population has led to an increased demand for fuels. The result is the prices of fuels are reaching new heights every day. Using low-cost feedstocks such as rendered animal fats in biodiesel production will reduce biodiesel expenditures. One of the low-cost feedstocks for biodiesel production from poultry feathers. This paper describes a new and environmentally friendly process for developing biodiesel production technology from feather waste produced in poultry industry. Transesterification is one of the well-known processes by which fats and oils are converted into biodiesel. The reaction often makes use of acid/base catalyst. If the material possesses high free fatty acid then acid catalyst gives better results. The data resulted from gas chromatography (GC) revealed these percentages for fatty acid compositions: myristic acid, palmitic acid, stearic acid, oleic acid, linoleic acid and arachidonic acid. The biodiesel function group was analyzed by using FTIR. This study concluded that the rooster feathers have superior potential to process them into biodiesel than broiler chicken feathers fat because of fatty acid composition values and it has important properties of biodiesel.