Objective: To examine if a homeopathic mother tincture (Phytolacca Decandra) is capable of precipitating silver nanoparticles from silver nitrate (AgNO₃) and to characterize the biosynthesized nanoparticles for evaluating their biological activities.

Methods: A total of 100 mg of AgNO₃ was added to 20 mL of Milli-Q water and stirred vigorously. Then 5 mL of the homeopathic mother tincture of Phytolacca Decandra (ethanolic root extract of Phytolacca decandra) was added and stirred continuously. Reduction took place rapidly at 300 K and completed in 10 min as shown by stable light greenish-yellow color of the solution which gave colloid of silver nanoparticles. The colloid solution was then centrifuged at 5 000×g to separate the nanoparticles for further use. The nanoparticles were characterized by spectroscopic analysis, particle size analysis and zeta potential measurements, and morphology was analyzed by atomic force microscopy. The drug-DNA interaction was determined by circular dichroism spectrophotometry and melting temperature profiles by using calf thymus DNA as the target. The biological activities were determined using a cancer cell line A549 in vitro and using bacteria Escherichia coli and fungus Saccharomyces cerevisiae as test models.

Results: Phytolacca Decandra precipitated silver nanoparticles in ambient conditions. The nanoparticles had 91 nm particle size, with polydispersity index of 0.119 and zeta potential of –15.6 mV. The silver nanoparticles showed anticancer and antibacterial properties, but no clear antifungal properties.

Conclusion: This could be a novel environment-friendly method to biosynthesize silver nanoparticles using a cost-effective, nontoxic manner. The homeopathic mother tincture may utilize this property of nano-precipitation in curing diseases or disease symptoms.

Key words: silver nitrate, metal nanoparticles, Phytolacca decandra, homeopathy, biosynthetic pathways