Green synthesis of silver nanoparticles at low temperature in a fast pace with unique DPPH radical scavenging and selective cytotoxicity against MCF-7 and BT-20 tumor cell lines

"Black Peel Pomegranate" is a rare pomegranate cultivar that its specific features are still uncovered particularly in the bio-nano researches. The present study was organized to evaluate this pomegranate's potential in the biosynthesis of silver nanoparticles as well as bio-medical activities. According to the results, the pomegranate peel extract incredibly inhibited 100 % of DPPH free radicals (EC(50) = 5 μg/mL). This extract also induced more than 70 % cell death in the treated breast tumor cell lines, BT-20 and MCF-7. Interestingly, the extract was capable of biosynthesis very stable and small (15.6 nm) silver nanoparticles at ambient temperature in an ultra-fast pace. Likewise, these nanoparticles inhibited 77 % of DPPH free radicals (EC(50) = 9 μg/mL). Although this antioxidant capacity was lower than that of the extract, instead, the anticancer activity of the synthesized nanoparticles was significantly enhanced, so that they led to more than 81 % and 89 % cell death in the breast tumor cell lines BT-20 and MCF-7, respectively. Considerably, neither the extract nor the biosynthesized silver nanoparticles, showed significant toxicity against non-tumor cell lines (L-929) at the same concentrations. These features of the biosynthesized nanoparticles were quite outstanding in comparison with chemical/commercial ones. Overall, the present study introduces black peel pomegranate as a worthy bio-agent in the biosynthesis of silver nanoparticles with unique activities as well as a cancer treatment.