Search

In this study, a sustainable and eco-friendly method was used to prepare zinc oxide nanoparticles (ZnO-NPs) using a sea cucumber aqueous extract. Then, ZnO-NPs were characterized by instrumental analysis (UV-vis, HR-TEM, XRD, FT-IR, and DLS) and evaluated for their possible antibacterial, antifungal, and insecticidal activities. Additionally, the toxicity of ZnO-NPs was evaluated in vivo against Nile Tilapia (Oreochromis niloticus). The sea cucumber was collected from the Gulf of Suez (Red Sea) at Al-Ain Al-Sokhna coast in Egypt and identified as Holothuria impatiens. The prepared Hi-ZnO-NPs peaked at 350 nm in UV–Vis spectral analysis. They showed quasi-spherical shaped particles with sizes ranging from 13 nm to 47 nm and a predominate size of 26 nm as indicated by HR-TEM. The XRD pattern of Hi-ZnO-NPs revealed a crystalline phase with an average size of 17.2 nm as calculated by Debye–Scherrer equation. FTIR analysis revealed the possible role of H. impatiens biological molecules in the biosynthesis process of ZnO-NPs. Hi-ZnO-NPs showed a negative zeta potential of −19.6 mV, demonstrating moderate stability. Biosynthesized Hi-ZnO-NPs revealed broad antimicrobial activity against Gram-positive bacteria (S. aureus ATCC 25923 and E. feacalis), Gram-negative bacteria (S. typhi, K. pneumonia and E. coli), and filamentous fungi (Aspergillus niger). Hi-ZnO-NPs demonstrated larvicidal activity against the mosquito, Culex pipiens (LC50 = 2.756 ppm and LC90 = 9.294 ppm), and adulticidal action against the housefly, Musca domestica (LD50 = 4.285 ppm and LD90 = 22.847 ppm). Interestingly, Hi-ZnO-NPs did not show mortality effects against Nile tilapia fish (Oreochromis niloticus), highlighting the potential safety of Hi-ZnO-NPs to highly exposed, non-target organisms. However, histopathological and hematological investigations provided dose-dependent impacts of Hi-ZnO-NPs to Nile tilapia. Overall, data provide an eco-friendly approach for synthesizing novel Hi-ZnO-NPs with multiple biomedical properties and potentially low toxicity to Nile tilapia fish. [ABSTRACT FROM AUTHOR]

Utility of sulfadiazine and sulfaguanidine in synthesis of new series of pyrazoles and 2-pyridones is described. Diazotization of sulfadiazine that results in formation of diazonium salt 2 followed by coupling of the latter with active methylene compounds leads to hydrazinyl derivatives 3a–3d. Heterocyclization of compounds 3a–3c with hydrazine derivatives gives to a series of pyrazole derivatives 4–6. Similarly, a series of pyrazole derivatives 12–14 is developed from sulfaguanidine. Condensation of hydrazinyl derivatives 3a–3c with cyanoacetamide in the presence of a catalytic amount of piperidine gives 2-oxonicotinonitriles 15a–15c. Tests of the new synthesized compounds against four pathogenic gram (+ve) and gram (−ve) bacteria demonstrate their activity higher than that of the standard Amoxicillin. [ABSTRACT FROM AUTHOR]

5-Acetyl-3-amino-4-aryl-6-methylthieno[2,3-b]pyridine-2-carboxamides (1a,b) were reacted with aromatic aldehydes or with some cycloalkanones to give the corresponding tetrahydropyridothienopyrimidinone derivatives 2a-f and 4a-d. The reaction of compound 1b with urea and/or carbon disulfide has been carried out and their products were identified. Some representative compounds were screened in vitro for their antimicrobial activities. [ABSTRACT FROM AUTHOR]