Green synthesis and characterization of a nanocomposite <i>Petroselinum crispum </i>(PcNps) and evaluation of its effect on the inhibition of <i>Pseudomonas aeruginosa</i> before and after loading the antibiotic erythromycin

Pseudomonas aeruginosa is a multidrug-resistant bacteria. Therefore, it has become necessary to use new methods, including the process of delivering treatment using nanomaterials manufactured using green methods. The present study explores the antibacterial effects of a green-synthesized nanocomposite from Petroselinum crispum (parsley) against Pseudomonas aeruginosa. The nanocomposite was prepared using an environmentally friendly method and characterized using Atomic Force Microscopy (AFM) and Fourier Transform Infrared (FTIR) spectroscopy. AFM results revealed that the root mean square height (Sq) of the parsley extract was 138 nm, while the nanocomposite (PcNps) measured 111 nm, a difference of 27 nm. The texture direction (Std) of the extract was 933 nm, compared to 667 nm for the nanocomposite. The maximum peak height (Sp) for the nanocomposite was 279 nm, which increased to 293 nm after converting the parsley extract into the nanocomposite. The maximum pit height (Sv) was 654 nm for the extract and 374 nm for the nanocomposite.FTIR analysis confirmed that the antibiotic loading showed positive results, with significant shifts observed in the spectra before and after loading. The antibacterial activity of the nanocomposite was significantly enhanced when combined with the antibiotic. The inhibition zone reached 21.00 ± 1.41 mm (p ≤ 0.05) with the antibiotic-nanocomposite combination. At a concentration of 5 µg (C1 PcNps/ER T5), the inhibition zone was 17.75 ± 1.50 mm (p ≤ 0.005), while at 10 µg, the zone was 10.25 ± 0.25 mm. These results demonstrate the effectiveness of the green nanocomposite, especially in combination with antibiotics, for inhibiting bacterial growth and show its potential as an antimicrobial agent.