Evaluating the biomedical and environmental safety of selenium nanoparticles synthesized from black pepper seed extract

Abstract

In recent times, sustainable synthesis of selenium nanoparticles (Se NPs) has seen a significant rise in research, focusing primarily on microbial and plant polysaccharide-based approaches for various bioapplications. However, there are limited studies on the use of extracts from herbal spice plants as capping agents for Se NPs. Therefore, this study investigates the pioneering synthesis of Se NPs using black pepper (Piper nigrum) seed extract (PSe NPs) and assesses their antioxidant properties, hemolytic potential, antibacterial and antibiofilm activities, cytotoxicity, phytotoxicity, in vivo toxicity in zebrafish embryos, and their effectiveness in prolonging the shelf life of food materials. The green-synthesized PSe NPs were thoroughly physicochemically characterized and found to be sphere-shaped with a medium diameter of 10–100 nm. The PSe NPs exhibited substantial antibacterial effects, being more effective against S. aureus (Gram-positive)than against S. typhi (Gram-negative). Furthermore, PSe NPs significantly inhibited MRSA biofilm growth at 500 μg/mL and showed notable antioxidant activity compared to standard gallic acid. Also at 500 μg/mL, PSe NPs induced significant hemolysis, whereas inferior concentrations did not. Cytotoxicity evaluations using the MTT assay revealed that PSe NPs significantly reduced the viability of human normal embryonic kidney (HEK 293) cells and human cervical cancer (HeLa) cells after 24 hours of treatment at concentrations of 0.1–500 μg/mL. This cytotoxic effect was associated with apoptosis, as shown by acridine orange/ethidium bromide staining. In phytotoxicity assays, PSe NPs revealed significant effects on seed germination and root and shoot growth of the mung bean (Vigna radiata). The zebrafish embryotoxicity assay indicated that PSe NPs at 500 µg/mL affected embryo morphology, mortality and survival rates 96 hours after fertilization. Furthermore, the application of PSe NPs gel coatings effectively reduced weight loss and extended the shelf life of fruits such as apples and pears, maintaining their natural appearance.