Nanotherapy for Cancer and Biological Activities of Green Synthesized AgNPs Using Aqueous Saussurea costus Leaves and Roots Extracts

Abstract

Background/Objectives: Nanoparticles derived from medicinal plants are gaining attention for their diverse biological activities and potential therapeutic applications. Methods: This study explored the antioxidant, anti-inflammatory, anti-tumoral, and antimicrobial properties of green synthesized silver nanoparticles (AgNPs) using the aqueous leaf and root extracts of Saussurea costus (S. costus). The physicochemical characterizations of both biosynthesized AgNPs using the aqueous leaf extract (L-AgNPs) and root extract (R-AgNPs) were examined using UV spectroscopy, fluorescence spectroscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, dynamic light scattering, and Fourier-transform infrared spectroscopy. The antioxidant activity measured using ABTS, DPPH, and FRAP assays showed that AgNPs, particularly from roots, had higher activity than aqueous extracts, attributed to phenolic compounds acting as capping and antioxidant agents. Results: Enzyme inhibition studies indicated that AgNPs exhibited remarkable anti-inflammatory effects, inhibiting COX-1, 5-LOX, and secreted PLA₂ enzymes by over 99% at 120 µg/mL, comparable to standard drugs. The anti-tumoral effects were evaluated on the human cancer cell lines HCT-116, LoVo, and MDA-MB-231, with AgNPs inhibiting cell proliferation dose-dependently and IC₅₀ values between 42 and 60 µg/mL, demonstrating greater potency than extracts. The AgNPs also showed enhanced antimicrobial activities against various microbial strains, with IC₅₀ values as low as 14 µg/mL, which could be linked to nanoparticle interactions with microbial cell membranes, causing structural damage and cell death. Conclusions: These findings suggest that S. costus-derived AgNPs are promising natural, biodegradable agents for various biological applications and potential new therapeutic agents, necessitating further research to explore their mechanisms and applications.

Keywords: anticancer therapies; green biotechnology; medicinal plants; nanotechnology.

Figure 1

The possible formation mechanism of Ag nanoparticles using S. costus leaf and root extracts.

Figure 2

UV analysis spectra of L-AgNPs and R-AgNPs.

Figure 3

Fluorescence emission spectra of (A) L-AgNPs and (B) R-AgNPs.

Figure 4

TEM images for the synthesized L-AgNPs (A) and R-AgNPs (B). Histograms of the particle size distributions of L-AgNPs (C) and R-AgNPs (D).

Figure 5

EDX spectra of (A) L-AgNPs and (B) R-AgNPs.

Figure 6

XRD spectra of (A) L-AgNPs and (B) R-AgNPs.

Figure 7

DLS analysis of (A) L-AgNPs and (B) R-AgNPs.

Figure 8

FTIR spectra of (A) L-AgNPs and S. costus leaf extract (B) R-AgNPs and S. costus root extract.

Figure 9

Antioxidant activity of AgNPs synthesized from S. costus extracts and determined by ABTS, DPPH, and FRAP methods. Results presented as the mean ± SD (n = 3) are expressed as GAE in mg/L (A) and as % of radical scavenging or as % of Fe³⁺ reduction in both ABTS and DPPH methods or in the FRAP method (B). L extract: aqueous leaves extract; R extract: aqueous roots extract; L-AgNPs: AgNPs prepared using L extract; R-AgNPs: AgNPs prepared using R extract. The asterisk indicates significant differences between experimental groups within a column. * represents p < 0.05; ** represents p < 0.01.

Figure 10

Evaluation of 5-LOX, COX, and sPLA₂ inhibition properties of AgNPs synthesized from S. costus extracts. Several concentrations ranging from 20 to 120 µg/mL of S. costus root and leaf extracts and their silver nanoparticles AgR and AgL were used to inhibit 5-LOX (A), COX (B), h-PLA₂-V (C), and DrPLA₂-IIA (D). NGDA at 100 µM, diclofenac at 1 µM, and TEPC at 20 µM served as positive controls. Results are presented as the mean ± SD (n = 3). L extract: aqueous leaves extract; R extract: aqueous roots extract; L-AgNPs: AgNPs prepared using L extract; R-AgNPs: AgNPs prepared using R extract. * represents p < 0.05; ** represents p < 0.01.

Figure 11

Cytotoxic potential of AgNPs synthesized from S. costus extracts against human colorectal HCT-116 (A), LoVo (B), and breast cells MDA-MB-231 (C). Cells were treated with several concentrations of extracts and silver nanoparticles during 24 h, from 20 µg/mL to 120 µg/mL. MTT assay was used to quantify viable cells. Current results are presented as the mean ± SD (n = 3 assays). L extract: aqueous leaves extract; R extract: aqueous roots extract; L-AgNPs: AgNPs prepared using L extract; R-AgNPs: AgNPs prepared using R extract. The asterisk indicates significant differences between experimental groups within a column. * represents p < 0.05; ** represents p < 0.01.