Green-synthesized silver-copper nanocomposites from Sargassum latifolium: antibacterial, anticancer, and in silico pharmacokinetic evaluation

Abstract

Green synthesis of nanocomposites is an eco-friendly approach compared with conventional methods. Sargassum latifolium is a marine microalgae rich in bioactive compounds and represents a promising natural resource for the green synthesis of nanomaterials. This work presents a green protocol for synthesizing, characterizing, and bioactivity of Ag/Cu NC using Sargassum latifolium extract. In this context, FTIR analysis showed the involvement of phytochemicals in reducing and stabilizing metal ions. Ag/Cu NC revealed moderate colloidal stability with a zeta potential of - 19.4 mV and an average particle size of 430.0 nm (PDI = 0.408), as evidenced by DLS analysis. EDX and XRD analyses verified a CuO-dominant phase (28.46 wt%) and a crystalline structure containing copper oxide and silver nanoparticles. Although the reduction in phytochemical contents, Ag/Cu NC (IC₅₀ = 0.148 ± 1.27 mg/mL), maintained its antioxidant potential compared to S. latifolium extract (IC₅₀ = 0.108 ± 1.54 mg/mL). Ag/Cu NC revealed privileged antibacterial activity against a series of pathogenic bacterial species, for instance, B. subtilis (38.0 ± 1.54 mm) and S. epidermidis species (25.0 ± 1.40 mm) as demonstrated by disc diffusion assay. The MIC results established the potential inhibitory of the nanocomposite against B. subtilis (0.692 μg/mL). The MTT assays revealed a dose-dependent cytotoxicity of Ag/Cu NCs, with HCT116 cells showing the highest sensitivity (IC₅₀ = 8.17 µg/mL), followed by HepG2 cells (IC₅₀ = 16.71 µg/mL) and WI-38 cells exhibiting the lowest cytotoxicity (IC₅₀ = 84.20 µg/mL). ADME toxicity results indicated moderate to high absorption in HepG2 and HCT116 cells, with significant distribution and metabolism observed at 5-10 µg/mL concentrations. WI-38 cells showed low absorption, distribution, and metabolism. Excretion was minimal across all cell lines. These findings suggest that Ag/Cu NCs exhibit selective cytotoxicity in cancer cells, with limited toxicity in normal cells. Our results in this work indicate the high efficiency of Ag/Cu NC as a novel hybrid in combating oxidative stress, and inhibiting the growth of cancer cells. The study presents an efficient nanocomposite with functional properties of nanomaterials integrated with the bioactivity of natural phytochemicals, paving the way for applications in pharmaceutical and environmental fields.

Keywords: Sargassum latifolium; Ag/Cu nanocomposite; Anti colon and liver cancer; Antibacterial; Characterization.