Green synthesis of ZnO/Fe3O4 nanocomposites from Citrus reticulata peel: antibacterial activity against MDR Acinetobacter baumannii, CRISPR-Cas gene modulation, and anticancer potential.
PMID 42395789 | PMCID PMC13326584 | DOI 10.1039/d6ra02362b · RSC advances · 2026
The emergence of multidrug-resistant (MDR) Acinetobacter baumannii necessitates the development of alternative antimicrobial strategies. In this study, ZnO/Fe3O4 nanocomposites (NCs) were green-synthesized using Citrus reticulata peel extract and evaluated for antibacterial, CRISPR-Cas gene modulation, anticancer, and antioxidant activities. Phytochemical profiling by GC-MS and HPLC confirmed a terpene- and polyphenol-rich composition supporting nanoparticle formation and stabilization. The synthesized NCs were characterized by UV-vis, FTIR, and XRD analyses, supporting the formation of crystalline ZnO and Fe3O4 phases, while TEM revealed nanoscale morphology (55.64 ± 24.2 nm) with hydrodynamic size of ∼181.3 nm and a zeta potential of +2.64 mV. Fifteen clinical A. baumannii isolates were identified, among which nine exhibited multidrug-resistant (MDR) profiles. CRISPR-associated genes were screened in the MDR isolates, and four isolates harboring the target genes were selected for further molecular analyses. The ZnO/Fe3O4 NCs exhibited antibacterial activity with inhibition zones ranging from 17 to 24 mm and MIC values of 250-500 µg mL-1. TEM analysis of treated bacteria demonstrated severe structural damage, including membrane disruption and cytoplasmic leakage. Furthermore, sub-MIC exposure resulted in downregulation of CRISPR-associated genes (Cas1: 0.61-0.98; Csy1: 0.54-0.95; Csy3: 0.70-0.83). Cytotoxicity assays revealed selective antiproliferative effects against Caco-2 colorectal cancer cells (IC50 = 60.7 µg mL-1) compared to normal Vero cells (IC50 = 254.66 µg mL-1), accompanied by increased apoptosis (15.8%) and G2/M cell cycle arrest (39.7%). Additionally, the NCs exhibited concentration-dependent antioxidant activity, reaching up to 69.44% (DPPH), 76.12% (ABTS), 62.24% (H2O2 scavenging), 56.13% (metal chelation), and 63.52% (reducing power). Overall, these findings demonstrate that green-synthesized ZnO/Fe3O4 NCs are multifunctional nanomaterials with promising antibacterial, anticancer, and antioxidant properties.
Validated evidence
| Type | Entity | Source evidence | Confidence | Extractor |
|---|---|---|---|---|
| phenotype | colorectal cancer | “Cytotoxicity assays revealed selective antiproliferative effects against Caco-2 colorectal cancer cells (IC50 = 60.7 µg mL-1) compared to normal Vero cells (IC50 = 254.66 µg mL-1), accompanied by increased apoptosis (15.8%) and G2/M cell cycle arrest (39.7%).” | 0.98 | phenotype_alias_lexicon_v2 |