Novel Metformin-Based Schiff Bases: Synthesis, Characterization, and Antibacterial Evaluation

Abstract

Novel Schiff bases of metformin hydrochloride and (ortho)para-nitrobenzaldehyde were synthesized by employing two efficient environmentally friendly methods, namely, stirring and microwave-assisted methods using water as the solvent. The advantage of microwave irradiation over the other methods was represented in the reduction of reaction time and wastes, and good yields; however, water in both methods plays the role of eco-friendly solvent. The structural properties of the (ortho)para-isomer products were analyzed by elemental analysis, Fourier transform infrared (FTIR) spectroscopy, UV-Visible (UV-Vis) spectroscopy, 1H nuclear magnetic resonance (NMR) spectroscopy, 13C NMR spectroscopy, mass spectroscopy, and differential scanning calorimetry (DSC). The newly synthesized compounds were screened for their antibacterial activity against selected Gram-positive (ATCC 25923, ATCC 43300, and ATCC 29212) and Gram-negative (ATCC 25922, ATCC 27853, and ATCC 700603) bacteria using the agar well diffusion method. Compared with the standard drug streptomycin, both Schiff bases exhibited moderate bactericidal activity against the tested bacteria with higher values of ortho-nitro compared with the para-nitro isomer; however, no effect on ATCC 43300 and ATCC 27853 was observed under the experimental conditions employed.

Pomegranate Peel Extract-Mediated Green Synthesis of ZnO-NPs: Extract Concentration-Dependent Structure, Optical, and Antibacterial Activity

“…Similarly, disks of AzM and DW were also prepared and used as positive and negative controls, respectively. e paper disks were placed aseptically on the surface of bacterially seeded Petri dishes and incubated at 37 °C for 21-22 h. e zone of inhibition (ZOI) was determined by measuring the diameter of the inhibition area in mm [19,20].…”

Gut Microbiome Influences the Efficacy of PD-1 Antibody Immunotherapy on MSS-Type Colorectal Cancer via Metabolic Pathway

“…The mice were divided into four following 4 groups. Group 1 mice were treated with a mix of ampicillin (1 mg/ml), streptomycin (5 mg/ml), and colistin (1 mg/ml) in sterile drinking water (Asc group) (Al-Qadsy et al, 2020;Yu and Zhao, 2020). Group 2 mice were treated with vancomycin alone (0.25 mg/ml) in sterile drinking water (Vanc group) (Liu et al, 2020).…”

Carbon dots derived from metformin by electrochemical synthesis with broad-spectrum antibacterial properties

“…The peaks at 1688.6 cm −1 and 1057.5 cm −1 corresponded to the stretching vibrations of the CN and C–N bonds, respectively. 30,31 However, the FT-IR spectrum of the MCDs shows two new peaks at 3404.9 and 1728.0 cm −1 , which are assigned to the stretching vibrations of O–H and N–CO, respectively. MCDs and MET have similar functional groups of CN and –NH 2 ; however, new functional groups of –OH and CO are also displayed in MCDs, indicating that the raw materials gradually oxidized and polymerized during electrooxidation.…”