Harnessing Plant-Based Nanoparticles for Targeted Therapy: A Green Approach to Cancer and Bacterial Infections

Abstract

This study investigates the antioxidant, antimicrobial, and antitumor activities of Taraxacum officinale (Dandelion) and Artemisia annua (Sweet Wormwood) extracts, along with their role in the green synthesis of gold (AuNPs) and silver nanoparticles (AgNPs). Bioreduction was achieved using aqueous and ethanolic extracts (100 mg/mL), enabling solvent-dependent comparisons. Nanoparticles were characterized using ultraviolet-visible spectroscopy (UV-Vis), fluorescence spectroscopy, scanning electron microscopy (SEM), dynamic light scattering (DLS), high-resolution transmission electron microscopy (HRTEM), and zeta potential analysis. Each technique revealed complementary aspects of nanoparticle morphology, size, and stability, with UV-Vis indicating aggregation states and DLS confirming solvent-related size variation even at 3-5% ethanol. Gold nanoparticles synthesized from Dandelion showed strong antibacterial activity against Staphylococcus aureus, while silver nanoparticles from both plants were effective against Escherichia coli. Cytotoxicity assays indicated that silver nanoparticles obtained from ethanolic Dandelion extract containing 3% ethanol in aqueous solution (AgNPsE_ETOH3%-D) significantly reduced LoVo (p = 4.58 × 10^-3) and MDA-MB-231 (p = 7.20 × 10^-5) cell viability, with high selectivity indices (SI), suggesting low toxicity toward normal cells. Gold nanoparticles synthesized from aqueous Dandelion extract (AuNPsEaq-D) also showed favorable SI values (2.16 for LoVo and 8.41 for MDA-MB-231). Although some formulations demonstrated lower selectivity (SI < 1.5), the findings support the therapeutic potential of these biogenic nanoparticles. Further in vivo studies and pharmacokinetic evaluations are required to validate their clinical applicability.

Keywords: antimicrobial; antitumoral; apoptosis; biosynthesis; green nanoparticles; nanoformulation; nanomedicine.

Figure 1

(a) UV–Vis spectra of (I) Artemisia annua (sweet wormwood, black line) and Taraxacum officinale (dandelion, magenta line) ethanol extracts, and (II) 1 mM AgNO₃ (blue line) and 0.5 mM HAuCl₄·3H₂O (red line); (b) UV–Vis spectra of silver nanoparticles synthesized with dandelion extract in aqueous solution (AgNPsEaq-D, I—black line) and in ethanol (AgNPsE_ETOH-D, II—red line). Inset: color change from pale yellow to brown during AgNPs formation; (c) UV–Vis spectra of gold nanoparticles synthesized with dandelion extract in aqueous solution (AuNPsEaq-D, I—black line) and in ethanol (AuNPsE_ETOH-D, II—red line). Inset: color change to violet during AuNPs formation; (d) UV–Vis spectra of silver nanoparticles synthesized with sweet wormwood extract in aqueous solution (AgNPsEaq-SW, I—black line) and in ethanol (AgNPsE_ETOH-SW, II—red line). Inset: color change to brown during AgNPs formation; (e) UV–Vis spectra of gold nanoparticles synthesized with sweet wormwood extract in aqueous solution (AuNPsEaq-SW, I—black line) and in ethanol (AuNPsE_ETOH-SW, II—red line). Inset: color change to red-violet during AuNPs formation. Inset: color change to red-violet during AuNPs formation.

Figure 2

(a) ATR-FTIR spectra for Dandelion-based sample: (I) E_ETOH-D; (II) AuNPsE_ETOH-D; (III) AgNPsE_ETOH-D; (b) ATR-FTIR spectra for Sweet Wormwood based sample: (I) E_ETOH-SW; (II) AuNPsE_ETOH-SW; (III) AgNPsE_ETOH-SW.

Figure 3

TEM for NPs (around 200 nanoparticles) aqueous extracts plant-based sample: (a) AgNPsEaq-SW (graph inset Mean = 11.7 nm SD = 4.6 Min = 6 max = 37); (b) AuNPsEaq-SW (Mean = 20.4 nm SD = 6.6 Min = 8 max = 41); (c) AuNPsEaq-D (Mean = 26.9 nm SD = 14.3 Min = 5 max = 133); (d) AgNPsEaq-D (Mean = 9.5 SD = 4.0 Min = 4 max = 25); TEM for NPs (around 200 nanoparticles) from ethanolic extracts from plant based sample: (e) AgNPsE_ETOH-SW (Mean = 12.2 nm SD = 4.5 Min = 5 max = 30); (f) AuNPsE_ETOH-SW; (g) AuNPsE_ETOHD; (h) AgNPsE_ETOH-D.

Figure 4

The MIC (µg/mL) and corresponding IZ (mm) for the all sample based on (a) Dandelion and (b) Sweet Wormwood.

Figure 5

Effect of different dilutions of sample based on dandelion and sweet wormwood on the viability (%) of human cancer cell lines, as follows: breast cancer (MDA-MB-231), the human colorectal adenocarcinoma cancer cell line LoVo, and the human umbilical vein endothelial cells HUVEC at (a) 24 h and (b) 48 h; (c) effect of different sample dilutions based on Dandelion and Sweet Wormwood on the viability (%) of HepG2 at 24 h and 48 h. Dilutions are given by the shade of the overlapping bar plots, with a lighter shade corresponding to less dilution.

Figure 6

Evolution of Selectivity Index (SI) values over time for all tumor cell lines. The figure illustrates the variation in Selectivity Index (SI) across different tumor cell lines over time. SI is calculated as the ratio between IC50 in normal cells and IC50 in tumor cells, indicating the specificity of nanoparticles towards cancer cells.

Figure 7

Selectivity Index and mechanisms of action of green-synthesized nanoparticles compared to conventional chemotherapeutic agents.