A Comparative Antibacterial, Antioxidant, and Antineoplastic Potential of (L.) Leaf Extract with Its Biologically Synthesized Gold Nanoparticles (R-AuNPs).

(), belonging to the family Apocynaceae, is a renowned medicinal herb for its different pharmacological activities such as antibacterial, antifungal, anti-inflammatory, and antiproliferative characteristics. This study has done a comparative assessment of the antibacterial, antioxidant, and anti-cancer activity of aqueous leaf extract (RSALE) with encapsulated gold nanoparticles (R-AuNPs). The R-AuNPs are prepared so that they are significant in size, monodispersed, and extremely stable. Their characterization was done by numerous parameters, including UV-visible spectroscopy (528 nm), transmission electron microscopy (17 d. nm), dynamic light scattering (68 d. nm), and zeta-potential (~-17 mV). Subsequently, a potent antibacterial activity was depicted via RSALE and R-AuNPs when examined by disc diffusion against various Gram-positive and Gram-negative bacterial strains. The obtained zones of inhibition of RSALE (100 mg/mL) were 34 ± 0.1, 35 ± 0.1, 28.4 ± 0.01, and 18 ± 0.01, although those of R-AuNPs (15 mg/mL) were 24.4 ± 0.12, 22 ± 0.07, 20 ± 0.16, and 17 ± 0.3 against (ATCC 25923), (ATCC 25922), (MTCC 8114), and (ATCC 19615), respectively. However, no zone of inhibition was obtained when tested against (MTCC 1771). Furthermore, the obtained MIC values for were 0.91, 0.61, and 1.15 mg/mL; for , 0.79, 0.36, and 1.02 mg/mL; for 0.42, 0.27, and 0.474 mg/mL; and for , 7.67, 3.86, and 8.5 mg/mL of pure RSALE, R-AuNPs, and Amoxicillin (control), respectively, incorporating that R-AuNPs have been shown to have a 1.4-fold, 2.1-fold, 1.5-fold, and 1.9-fold enhanced antibacterial activity in contrast to pure RSALE tested against , , , , and , respectively. Additionally, an enhanced antioxidant potential was detected in R-AuNPs compared to RSALE evaluated by the 2,2-Diphenyl-1-Picryl Hydrazyl Radical Scavenging (DPPH) Ferric reducing antioxidant power (FRAP) assay. The determined IC 50 values of RSALE and R-AuNPs were 0.131 ± 0.05 and 0.184 ± 0.02 mg/mL, and 0.110 ± 0.1 and 0.106 ± 0.24 mg/mL via the FRAP and DPPH assays, respectively. In addition, the anti-cancer activity against the human cervical cancer (Hela) cell line was evaluated, and the MTT assay results revealed that R-AuNPs (IC 88.3 µg/mL) had an enhanced anti-cancer potential in contrast to RSALE (171.5 µg/mL). Subsequently, the findings of this study indicated that leaves and their nanoformulation can be used as a potent source for the treatment of the above-mentioned complications and can be used as a possible agent for novel target-based therapies for the management of different ailments.