The research highlights the environmentally sustainable biosynthesis of silver nanoparticles from fresh leaves of the herbal medicinal plant Moringa oleifera. They may have been used as anti‐inflammatory, anticancer, and antimicrobial agents. M. oleifera extract both reduces and stabilizes silver nanoparticles (AgNPs). Optimum factors needed for AgNP biosynthesis were studied using a central composite design (CCD) matrix. Ultraviolet‐visible (UV–Vis) absorption spectroscopy, transmission electron microscopy, and Fourier‐transform infrared spectroscopy were used to confirm and characterize the synthesized AgNPs. The biogenic AgNPs demonstrated substantial antibacterial potential against the pathogenic strains Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus, and Bacillus subtilis. The antioxidant activity of biosynthesized AgNPs with M. oleifera extract increased from 11.96% when the concentration of the extract was 4 mg/mL to 63.79% at a plant concentration of 20 mg/mL. This research provides an easy and cost‐effective technique for the production of stable nanoparticles, with an evaluation of their bioactivity.

Background: Antibiotic resistance is a global problem; especially the multidrug-resistant bacteria are a serious and fatal problem in the intensive care unit. Interestingly, biosynthesized silver nanoparticles are the promising key to eliminate these microbes. Using Pseudomonas aeruginosa supernatant is an easy and cheap method in silver nanoparticle biosynthesis. The biosynthesis conditions were adjusted, and the profiling of the biosynthesized silver nanoparticles was confirmed. Results: The UV spectroscopy at a wavelength at 400 nm was 0.539 A.U., transmission electron microscope showed nanoparticles were homogeneous with a square and spherical shape, its average size 20 nm, The capping material and the existence of silver nanoparticles were confirmed using Fourier transform infrared spectroscopy, and energy dispersive X-ray spectroscopy. The minimum inhibitory concentration was 1 mg/ml against multidrug-resistant bacteria, and LC50 was 62.307 μg/ml on the hepatocellular carcinoma cell line. Conclusions: Microbial-synthesized silver nanoparticles have a potential application to combat multidrug-resistant bacteria, especially in the intensive care unit.

A strain of Bacillus cereus was isolated from the Saudi Red Sea coast and identified based on culture features, biochemical characteristics, and phylogenetic analysis of 16S rRNA sequences. EPSR3 was a major fraction of exopolysaccharides (EP_S) containing no sulfate and had uronic acid (28.7%). The monosaccharide composition of these fractions is composed of glucose, galacturonic acid, and arabinose with a molar ratio of 2.0: 0.8: 1.0, respectively. EPSR3 was subjected to antioxidant, antitumor, and anti-inflammatory activities. The results revealed that the whole antioxidant activity was 90.4 ± 1.6% at 1500 µg/mL after 120 min. So, the IC₅₀ value against DPPH radical found about 500 µg/mL after 60 min. While using H₂O₂, the scavenging activity was 75.1 ± 1.9% at 1500 µg/mL after 60 min. The IC₅₀ value against H₂O₂ radical found about 1500 µg/mL after 15 min. EPSR3 anticytotoxic effect on the proliferation of (Bladder carcinoma cell line) (T-24), (human breast carcinoma cell line) (MCF-7), and (human prostate carcinoma cell line) (PC-3) cells. The calculated IC50 for cell line T-24 was 121 ± 4.1 µg/mL, while the IC₅₀ for cell line MCF-7 was 55.7 ± 2.3 µg/mL, and PC-3 was 61.4 ± 2.6 µg/mL. Anti-inflammatory activity was determined for EPSR3 using different methods as Lipoxygenase (LOX) inhibitory assay gave IC₅₀ 12.9 ± 1.3 µg/mL. While cyclooxygenase (COX-2) inhibitory test showed 29.6 ± 0.89 µg /mL. EPSR3 showed potent inhibitory activity against methicillin-resistant Staphylococcus aureus (MRSA) and coagulase-negative staphylococci. The exposure times of EPSR3 for the complete inhibition of cell viability of methicillin resistant S. aureus was found to be 5% at 60 min. Membrane stabilization inhibitory gave 35.4 ± 0.67 µg/mL. EPSR3 has antitumor activity with a reasonable margin of safety. The antitumor activity of EPSR3 may be attributed to its content from uronic acids with potential for cellular antioxidant and anticancer functional properties.