부산대학교 도서관

The study focuses on the green synthesis of silver nanoparticles (AgNPs) using Calotropis gigantea leaf ethanol extract, exploring their potential pharmacological applications involving biological activity. The investigation involves comprehensive characterization techniques, including UV-visible inspection, FT-IR, SEM, TEM, XRD, and EDX. Various secondary metabolites, such as tannins, alkaloids, flavonoids, and polyphenols, were identified in the synthesized AgNPs. UV-Vis spectroscopy at 430 nm revealed surface plasmon resonance, corroborating with FT-IR bands at 2066 and 1607 cm− 1, associated with aldehyde carbon-hydrogen stretching and aromatic carbon-carbon vibration. The AgNPs exhibited a spherical-to-cubic shape, with SEM indicating particle sizes ranging from 10 to 25 nm. TEM analysis further detailed the synthesized AgNPs’ spherical shape, with an average diameter of 20 to 50 nm. The XRD analysis confirmed the crystalline nature of the AgNPs, with Bragg Reflection peaks consistent with JCPDS card no. 01-080-1439. The synthesized AgNPs demonstrated antioxidant properties through DPPH, ABTS, and superoxide anion scavenging activities. DPPH radical scavenging activity ranged from 21.54 to 92.31%, surpassing ascorbic acid. ABTS radical scavenging by green nanoparticles exhibited significant efficacy (19.25–89.41%), with IC50 values of 137 µg/mL (C. gigantea) and 52.34 µg/mL (quercetin). In superoxide anion scavenging, green nanoparticles demonstrated efficacy (17.65–87.41%) with IC50 values of 142 µg/mL (C. gigantea) and 53.43 µg/mL (quercetin). OH radical scavenging ranged from 16.24 to 82.55%, surpassing ascorbic acid, with IC50 values of 52.12 µg/mL (quercetin). Additionally, C. gigantea + AgNPs exhibited significant antibacterial properties, outperforming amoxicillin. Notably, against Escherichia coli, the zone of inhibition at 50 µg/ml was 10.73 ± 0.43, increasing to 18.74 ± 0.73 at 250 µg/ml. Staphylococcus aureus displayed inhibition values of 13.16 ± 0.43 and 21.72 ± 0.73 at 50 µg/ml and 250 µg/ml, respectively, while Pseudomonas aeruginosa exhibited values of 12.72 ± 0.75 and 19.54 ± 0.54 at 50 µg/ml and 250 µg/ml. This study underscores the diverse applications and notable antioxidant and antibacterial efficacy of C. gigantea + AgNPs, showcasing their potential in pharmacological applications involving biological activity. The comprehensive characterization techniques employed provide a thorough understanding of the synthesized nanoparticles, paving the way for further research and development in the field.