Enhancing the medicinal potency of Colchicum luteum by forming biogenic silver nanoparticles: Antimicrobial, anticancer and antioxidant evaluation.

The goal of this study was to enhance the medicinal potency of the high-value Himalayan herb Colchicum luteum by synthesizing biogenic silver nanoparticles (CL-bAgNPs). The rapid increase in life-threatening diseases such as cancer, microbial infections and oxidative stress-related disorders represents a global health concern. Natural remedies, such as herbs, have been used for centuries due to their therapeutic properties, but their low efficiency in targeted delivery and slow onset of action often reduces their therapeutic impact. A combination of herbs with nanotechnology-based approaches has gained attention because it increases the medicinal efficiency of herbs. In this study, Colchicum luteum, a high-value medicinal Himalayan herb, was utilized for the synthesis of CL-bAgNPs. The bioactive compounds present in Colchicum luteum acted as natural reducing and stabilizing agents and facilitated the eco-friendly synthesis of CL-bAgNPs. Various experimental parameters were optimized to achieve maximum yield and stability of CL-bAgNPs. UV-visible spectrum revealed a distinct surface plasmon resonance peak at 425 nm, which confirms that CL-bAgNPs had been photo-fabricated using Colchicum luteum extract. Scanning electron microscopy and transmission electron microscopy revealed spherical morphology and size between 5 and 40 nm, dynamic light scattering measured an average hydrodynamic diameter of 56 nm with a polydispersity index of 0.245, zeta potential was -24.2 mV, indicating stability, and energy-dispersive X-ray spectroscopy confirmed elemental composition of the prepared CL-bAgNPs. To confirm enhancement in medicinal potency of Colchicum luteum, both CL-bAgNPs and extract of Colchicum luteum were tested against microbial pathogens (bacterial and fungal) and found that CL-bAgNPs exhibited stronger antimicrobial effects with minimum inhibitory concentration values ranging from 250 to 1000 μg/mL and minimum bactericidal concentration values from 500 to 1000 μg/mL, significantly outperforming the plant extract. Additionally, the DPPH assay showed 80.19 ± 1.2 % inhibition of free radicals using CL-bAgNPs, outperforming the plant extract in the antioxidant test. The anti-cancer activity of CL-bAgNPs was studied using the MTT assay, and it showed excellent results against the human breast and lung cancer cell lines. Finally, CL-bAgNPs demonstrated high biocompatibility, with almost 80 % viability in normal cells at the highest tested concentration, indicating no significant cytotoxicity. Thus, the CL-bAgNPs not only enhance the therapeutic efficacy of Colchicum luteum but also represent a promising, eco-friendly nanobiomedicine with potential applications in antimicrobial, antioxidant and targeted anticancer treatment.