Green fabrication of silver nanoparticles using Corallocarpus epigaeus (Hook.f.) Cogn. rhizome extract: phytochemical characterization and evaluation of antioxidant, antimicrobial, and anticancer activity against HT-29 cells.

Corallocarpus epigaeus is an ethnomedical plant with numerous bioactive phytochemicals but the potential of the plant in green nanotechnology and anticancer studies is underexplored. Phytochemical screening was conducted and AgNPs biosynthesis was done using rhizome extract as a reducing and capping agent. The nanoparticles were characterized using UV-Vis spectroscopy, GC-MS, FTIR, Raman spectroscopy, AFM, and SEM, DLS and Zeta potential analyser. Antioxidant activity was measured using Phosphomolybdenum assay, antibacterial using agar well diffusion with Escherichia coli (MTCC 40), (MTCC 121) and cytotoxicity of HT-29 colon cancer cells using MTT assay. Alkaloids were in large quantity, flavonoids, phenolics, saponins and phytosteroids were in moderate amounts and trace amounts of tannins and quinones. UV-Visible spectroscopy confirmed nanoparticle formation with a stable surface plasmon resonance peak at 430 nm. XRD analysis revealed a highly crystalline nanostructure with well-defined diffraction peaks, confirming the formation of nanocrystalline silver. DLS analysis indicated a predominant nanoscale population with an average hydrodynamic size of 55-86 nm, although some aggregation was observed. Zeta potential measurement (- 21.0 mV) suggested moderate colloidal stability due to phytochemical capping. SEM and AFM analyses confirmed predominantly spherical, moderately dispersed nanoparticles with nanoscale morphology with a 55 nm diameter. The AgNPs had a higher antioxidant capacity (0.0251 absorbance units) compared to crude extract (0.0078). It showed a strong antibacterial activity with the inhibition zones of 25 mm (B. subtilis) and 24 mm (E. coli) achievable at 150 µL. The AgNPs demonstrated a high level of cytotoxicity towards HT-29 cells with an IC50 of 31.2 ug/ml and-apoptotic morphology. AgNPs (55 nm) mediated by C. epigaeus rhizome exhibits good antioxidant, antibacterial and anticancer effects that can be used to justify the possibility of using C. epigaeus rhizome as plant-based nanotherapeutics. Moreover, the eco-friendly approach contributes to the global objectives of United Nations Sustainable Development Goal 3: Good Health and Well-Being, United Nations Sustainable Development Goal 9: Industry, Innovation and Infrastructure, and United Nations Sustainable Development Goal 12: Responsible Consumption and Production, by promoting sustainable nanotechnology, innovative biomedical research, and environmentally responsible production methods.