Unveiling the antibacterial and antifungal potential of biosynthesized silver nanoparticles from Chromolaena odorata leaves

Abstract

This research investigates the biogenic synthesis of silver nanoparticles (AgNPs) using the leaf extract of Chromolaena odorata (Asteraceae) and their potential as antibacterial and antifungal agents. Characterization techniques like ultraviolet-visible, Fourier transform infrared (FTIR), Dynamic light scattering and zeta potential (DLS), X-ray diffraction (XRD), transmission electron microscopy (TEM), and field emission scanning electron microscopy and energy-dispersive X-ray spectroscopy (FESEM-EDX) confirmed the formation of spherical (AgNPs). UV-vis spectroscopy reaffirms AgNP formation with a peak at 429 nm. DLS and zeta potential measurements revealed an average size of 30.77 nm and a negative surface charge (- 0.532 mV). Further, XRD analysis established the crystalline structure of the AgNPs. Moreover, the TEM descriptions indicate that the AgNPs are spherical shapes, and their sizes ranged from 9 to 22 nm with an average length of 15.27 nm. The X-ray photoelectron spectroscopy (XPS) analysis validated the formation of metallic silver and elucidated the surface state composition of AgNPs. Biologically, CO-AgNPs showed moderate antibacterial activity but excellent antifungal activity against Candida tropicalis (MCC 1559) and Trichophyton rubrum (MCC 1598). Low MIC values (0.195 and 0.390 mg/mL) respectively, suggest their potential as effective antifungal agents. This suggests potential applications in controlling fungal infections, which are often more challenging to treat than bacterial infections. Molecular docking results validated that bioactive compounds in C. odorata contribute to antifungal activity by interacting with its specific domain. Further research could pave the way for the development of novel and safe antifungal therapies based on biogenic nanoparticles.

Keywords: Chromolaena odorata; Antimicrobial activities; Green synthesis; Molecular docking; Silver nanoparticles.

Figure 1

(A) The aqueous solution of 1 mM AgNO₃. (B) C. odorata leaf extract. (C) Biosynthesis of CO-AgNPs from leaf extract of C. odorata.

Figure 2

UV–Vis spectrophotometer of synthesized CO-AgNPs.

Figure 3

XPS spectra of silver nanoparticles (a) XPS of silver nanoparticles, (b) XPS of Ag 3d.

Figure 4

(A) FESEM image of synthesized of CO-AgNPs. (B) EDX spectrum of synthesized CO-AgNPs showing the presence of silver (Ag).

Figure 5

(A) TEM image of synthesized of CO-AgNPs. (B) The selected area electron diffraction (SAED) pattern.

Figure 6

Antifungal activities (ZOI) of CO-AgNPs against fungi C. tropicalis (A), MIC microplate (B) and T. rubrum (C) and MIC microplate (D). Antibacterial activities (ZOI) of CO-AgNPs against bacteria S. aureus (E), MIC microplate (F); S. pyogenes (G), MIC microplate (H); E. coli (I), MIC microplate (J) and K. pneumoniae (K), MIC microplate assay (L). The agar well diffusion assay was indicated well as CO-AgNPs (a), Positive control (b) and Negative control (c). The MIC microplates were indicated well as solvent plant extract, Acetone (1), Ethanol (2), Methanol (3), Butanol (4), Diethyl ether (5), n-Hexane (6), Distilled water (7) and synthesis CO-AgNPs (8).

Figure 7

Histogram of antimicrobial activity of solvent extract and CO-AgNPs.

Figure 8

2D ligand interactions structure of the bioactive compounds 1–10 with C. albicans fungal target protein 5V5Z visualized by BIOVIA Discovery Studio.

Figure 9

Docking and interactive bonding mode pose (a) and 2D ligand interaction structure (b) of the compound Pctolinaringenin (7) with fungal (C. albicans) target protein 5V5Z visualized by BIOVIA Discovery Studio.

Figure 10

Docking and amino acid interactions (a), 2D ligand interaction structure (b), docking and interactive bonding mode pose (c), and 2D ligand interaction structure (d), of the compound Pctolinaringenin (7), with S. aureus bacterial target protein 1AD1 and E. coli bacterial target protein 1AJ0, visualized by BIOVIA Discovery, respectively.