Nanotechnology is rapidly evolving, with growing interest in synthesizing nanoparticles from natural sources, specifically plant-derived ones, like zinc oxide nanoparticles (ZnO-NPs), a process known as green synthesis. These nanoparticles are non-toxic, stable, versatile, and biodegradable, making them suitable for a broad range of biomedical applications, such as anticancer, anti-inflammatory, and antimicrobial activities. ZnO-NPs are used in diagnostics, drug delivery systems, biosensors, and therapeutic formulations due to their low toxicity, ability to create reactive oxygen species (ROS), and high surface area. Syzygium aromaticum [clove bud extract (CBE)] has antibacterial, anti-inflammatory, and anti-cancer effects used in the biosynthesis of the ZnO-NPs.
This study aims to biosynthesize and characterize ZnO-NPs using CBE and evaluate their anti-inflammatory, anticancer, and antimicrobial effects. It focuses on assessing the effects of CBE-ZnO-NPs on inflammation suppression, tongue carcinoma (HNO-97) cells, and bacterial inhibition mechanisms.
Clove buds were crushed and mixed with sterile distilled water to prepare the CBE. This mixture is simmered, filtered, and stored. 95 ml 0.01 M Zinc acetate dihydrate solution is mixed with 5 ml CBE to synthesize ZnO-NPs. The mixture was stirred at 70°C for 1 hour, and the pH was adjusted to ~8 with 0.1 M NaOH. The brown precipitate appearance confirmed the formation of nanoparticles. CBE-ZnO-NPs are characterized by energy dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET), dynamic light scattering (DLS), and Fourier-transform infrared spectroscopy (FTIR) to confirm the morphology, size, elemental, and surface composition. The anticancer effect was evaluated against HNO-97 cells using the sulforhodamine B (SRB) assay. The antibacterial effect was determined against Staphylococcus aureus, Bacillus cereus, Escherichia coli, and Pseudomonas aeruginosa. Anti-inflammatory effects were assessed using the mouse macrophage cell line (RAW 264.7).
This study used GraphPad Prism 9.0 for data analysis, one-way ANOVA was applied for antimicrobial effect, and mean ± standard deviation for three independent replicates.
The irregular shape of ZnO-NPs was confirmed by the SEM method, and the functional group responsible for bioactivity and stability was identified by FTIR. DLS method indicated an average particle size of 249.8 nm with the potential of zeta −3.38 mV. BET method revealed a high porosity of 30.039 m2/g and a mean particle size of 19.52 nm. CBE-ZnO-NPs showed mild anticancer activity against the tongue cancer cells [inhibitory concentration (IC₅₀)> 100 µg/mL], antibacterial activity [minimum inhibitory concentration (MIC) = 62.5 to 125 μg/mL], and anti-inflammatory activity (IC50= 69.3 µg/mL).
The green synthesis of ZnO-NPs using Syzygium aromaticum shows promise for biomedical applications. The CBE-ZnO-NPs indicate promising antibacterial effects against Gram-negative and Gram-positive bacteria, anticancer and anti-inflammatory effects. This approach aligns with the growing demand for eco-friendly and sustainable production of nanomaterials.
Future research must focus on optimizing synthesis, investigation of efficacy in vivo, and elucidating molecular mechanisms to improve the safety, efficacy, and environmental sustainability of next-generation nanotherapies.
Reference: Hussien NA, Khalil MAEF, Schagerl M, Ali SS. Green synthesis of zinc oxide nanoparticles as a promising nanomedicine approach for anticancer, antibacterial, and anti-inflammatory therapies. Int J Nanomedicine. 2025;20:4299-4317. doi:10.2147/IJN.S507214
