Biosynthesis of zinc oxide nanoparticles using Albizia lebbeck stem bark, and evaluation of its antimicrobial, antioxidant, and cytotoxic activities on human breast cancer cell lines

Figures & data

Figure 1 Synthesis of ZnO NPs: (A) Albizia lebbeck aqueous extract; (B) ZnO NPs.

Abbreviation: ZnO NPs, zinc oxide nanoparticles.

Figure 2 UV–visible spectra of ZnO NPs prepared with various concentrations of zinc nitrate at different (A) incubation time and (B) pH.

Abbreviation: ZnO NPs, zinc oxide nanoparticles.

Figure 3 Particle size distribution of synthesized ZnO NPs using Albizia lebbeck stem bark extract: (A) 0.1M, (B) 0.05M, and (C) 0.01M.

Abbreviation: ZnO NPs, zinc oxide nanoparticles.

Figure 4 FTIR spectra of Albizia lebbeck extract and synthesized ZnO NPs using various concentrations of zinc nitrate.

Abbreviations: FTIR, Fourier transform infrared; ZnO NPs, zinc oxide nanoparticles.

Figure 5 XRD pattern of 0.01M, 0.05M, and 0.1M synthesized ZnO NPs.

Abbreviations: XRD, X-ray diffraction; ZnO NPs, zinc oxide nanoparticles.

Figure 6 SEM images of ZnO NPs synthesized using Albizia lebbeck stem bark extract: (A) 0.1M, (B) 0.05M, and (C) 0.01M. EDX spectra of the ZnO NPs: (D) 0.1M, (E) 0.05M, and (F) 0.01M.

Abbreviations: EDX, energy-dispersive X-ray spectroscopy; SEM, scanning electron microscope; ZnO NPs, zinc oxide nanoparticles; cps/eV, counts per second per electron-volt.

Table 1 Antimicrobial activity of ZnO NPs in comparison with extract, zinc nitrate solution, DMSO, and antibiotics

Bacterial strains	Bacillus cereus (mean ± SEM)	Staphylococcus aureus (mean ± SEM)	Escherichia coli (mean ± SEM)	Klebsiella pneumoniae (mean ± SEM)	Salmonella typhi (mean ± SEM)
Standard ciprofloxacin (10 µg/disc)	10.7±0.56	10.3±0.56	14.0±0.20	11.0±0.30	12.53±0.50
ZnO NPs (0.1M)	8.83±0.42	4.50±0.30**	9.13±0.41**	7.30±0.29**	10.57±0.320
ZnO NPs (0.05M)	5.5±0.50**	5.67±0.29**	7.67±0.47**	3.33±0.28**	6.5±0.20**
ZnO NPs (0.01M)	3.33±0.29**	2.00±0.22**	4.67±0.15**	3.67±0.21**	1.00±0.10**
Albizia lebbeck extract	1.0±0.20**	1.5±0.20**	0.3±0.15**	1.0±0.10**	0.97±0.31**
Zinc nitrate solution (0.1M)	2.67±0.15**	2.33±0.29**	1.0±0.10**	1.33±0.21**	1.0±0.20**
DMSO (30%)	–	–		–	–

Notes: Results are presented as mean ± SEM of inhibition zone (mm) of at least triplicates (n≥3).

** P<0.01 vs control (standard group). (–) indicates no significant antibacterial activity.

Abbreviations: DMSO, dimethylsulfoxide; SEM, standard error of mean; ZnO NPs, zinc oxide nanoparticles.

Figure 7 Zone of inhibition of 0.1M synthesized ZnO NPs compared with extract, zinc nitrate solution, DMSO, and antibiotics: (a) extract, (b) zinc nitrate solution, (c) ZnO NPs, (d) DMSO, and (e) antibiotic (ciprofloxacin).

Abbreviations: DMSO, dimethylsulfoxide; ZnO NPs, zinc oxide nanoparticles.

Figure 8 H₂O₂ free radical scavenging activity of the biosynthesized ZnO NPs.

Notes: (A) H₂O₂ free radical scavenging activity of the biosynthesized ZnO NPs. (B) Predicted mechanism of ZnO NPs formation and its H₂O₂ free radical scavenging activity.

Abbreviation: ZnO NPs, zinc oxide nanoparticles.

Figure 9 Effect of 0.1M, 0.05M, and 0.01M synthesized ZnO NPs on the (A) viability of MDa-MB 231 cells, (B) viability of McF-7 cells, (C) proliferation of MDa-MB 231 cells, (D) proliferation of McF-7 cells. (E) Typical phase-contrast light-microscopy images obtained from tryphan blue exclusion assay of MDa-MB 231 and (F) McF-7 cell lines. Typical phase-contrast light-microscopy images (20×) of plasma membrane blebs (directed by an arrow) induced by synthesized ZnO NPs on (G) MDA-MB 231 and (H) MCF-7 cell lines (I) Predicted mechanism behind cytotoxic activity of biosynthesized ZnO NPs using A. lebbeck stem bark against breast cancer lines. *P<0.05, **P<0.01, ***P<0.0001.

Abbreviation: ZnO NPs, zinc oxide nanoparticles.

Figure 10 Summary of the synthesis and biomedical activity of biosythesized ZnO NPs.