Due to the indiscriminate use of antimicrobial drugs in the treatment of infectious diseases, human pathogenic bacteria have developed resistance to many commercially available antibiotics. Medicinal plants such as Convolvulus arvensis represent a renewable resource for the development of alternative therapeutic agents. This study aimed to evaluate the antibacterial activity of silver nanoparticles (AgNPs) biosynthesized from C. arvensis against two clinical antibiotic-resistant bacterial isolates. The pathogenic isolates were identified as Staphylococcus aureus MRSA and Escherichia coli ESBL using 16S rRNA gene sequencing. Silver nanoparticles were synthesized via a green synthesis approach, and their physicochemical properties were characterized using UV–Vis spectroscopy, scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, zeta potential, and dynamic light scattering (DLS). The synthesized C. arvensis–AgNPs exhibited a surface plasmon resonance peak at 475 nm and predominantly spherical morphology with particle sizes ranging from 102.34 to 210.82 nm. FTIR analysis indicated the presence of O–H, C–O, C–N, C–H, and amide functional groups. The nanoparticles showed a zeta potential of −18.9 mV and an average hydrodynamic diameter of 63 nm. The antibacterial activity of the biosynthesized AgNPs was evaluated against methicillin-resistant S. aureus (MRSA and ATCC 29213) and E. coli (ESBL and ATCC 25922) using agar diffusion, minimum inhibitory concentration (MIC), and minimum bactericidal concentration (MBC) assays. Inhibition zones ranged from 10 to 13 mm, with MIC and MBC values of 12.5–25 µg/mL and 25–50 µg/mL, respectively. In addition, the nanoparticles exhibited antioxidant activity (DPPH assay, IC₅₀ = 0.71 mg/mL) and anti-inflammatory effects as determined by protein denaturation inhibition. No cytotoxic effects were observed in the MCF-7 cell line at the MIC level. These findings suggest that C. arvensis–AgNPs have potential as natural antimicrobial, antioxidant, and anti-inflammatory agents.

The search for novel natural resources, such as extracts from algae and plant for use as reductants and capping agents for the synthesis of nanoparticles, may be appealing to medicine and nanotechnology. This study aimed to use Malva parviflora fruit extract as a novel source for the green synthesis of silver nanoparticles (AgNPs) and to evaluate their characterization. The results of biosynthesized AgNP characterization using multiple techniques, such as UV–Vis spectroscopy, scanning electron microscopy (SEM), FTIR analysis, and zeta potential (ZP), demonstrated that M. parviflora AgNPs exhibit a peak at 477 nm; possess needle-like and nanorod morphology with diameters ranging from 156.08 to 258.41 nm; contain –OH, C=O, C-C stretching from phenyl groups, and carbohydrates, pyranoid ring, and amide functional groups; and have a zeta potential of −21.2 mV. Moreover, the antibacterial activity of the M. parviflora AgNPs was assessed against two multidrug-resistant strains, including Staphylococcus aureus MRSA and Escherichia coli ESBL, with inhibition zones of 20.33 ± 0.88 mm and 13.33 ± 0.33 mm, respectively. The minimum bactericidal concentration (MBC) was 1.56 µg/mL for both. SEM revealed structural damage to the treated bacterial cells, and RAPD-PCR confirmed these genetic alterations. Additionally, M. parviflora AgNPs showed antioxidant activity (IC₅₀ = 0.68 mg/mL), 69% protein denaturation inhibition, and cytotoxic effects on MCF-7 breast cancer cells at concentrations above 100 µg/mL. These findings suggest that M. parviflora-based AgNPs are safe and effective for antimicrobial and biomedical applications, such as coatings for implanted medical devices, to prevent biofilm formation and facilitate drug delivery.

Samh (Mesembryanthemum forsskalii, M. cryptanthum) belongs to Aizoaceae family and is found in northern Saudi Arabia, primarily in desert or dry shrubland habitats. M. forsskalii is characterized by several nutritional and medicinal benefits. This study aimed to explore the phenotypic features of M. forsskalii and investigate the impact of exogenous plant growth regulators (PGRs) on this species using tissue culture techniques. Different auxin (naphthalene acetic acid (NAA), 2,4-dichlorophenoxyacetic acid (2,4-D) and indole butyric acid (IBA) in addition cytokinin (benzyl amino purine (BA), and kinetin (Ki) treatments were used. The phenotypic features of M. forsskalii included being decumbent to erect, with many terete succulent branches covered by epidermal bladder cells. Plant size determines its branching type, phyllotaxis, and inflorescence. Large plants have trichotomous branching; the two lower nodes have opposite decussate leaves; and compound dichasia. The flowers are pedicellate, perigynous, and have single, tricorporate pollen grains. Additionally, M. forsskalii has taproots, which differs from what was reported for M. forsskalii in previous studies in that it has fibrous roots. A 98% response rate was seen when the receptacle was used as an initiated explant. Adding BA to the MS medium also showed a significant increase in the size of the shoot system area and the number of roots. as well as the combined Ki + 2,4-D treatment had a significant effect on the callus volume. The callus color ranged from yellowish green to brown, and compact and rooty calli (callus cells differentiated into root hairs) were observed. This study investigated the phenotypic features of M. forsskalii (samh), and its micropropagation that had not been previously reported in the literature. Its branching type, phyllotaxis, and inflorescence were described. The flowers are pedicellate, and the pollen grains are single, tricorporate, and oblate. M. forsskalii has taproots, which differs from what was reported for M. cryptanthum (M. forsskalii) in previous studies in that it has fibrous roots. Therefore, the difference in the type of root may be an indication that the variety found in the Al-Jouf area is different than the previous varieties. This study was the first to examine the impact of exogenous PGR on M. forsskalii under tissue culture conditions. Based on the results of this study, the use of 2 mg/ml BA for M. forsskalii micropropagation and the combination of IBA and 2,4-D for callus induction experiments are recommended. Further molecular research on M. forsskalii is also recommended.

Laccase production was evaluated in 108 fungal isolates recovered from the eastern coast of Saudi Arabia, a critical element in environmental biodegradation and biotransformation. The most active isolate was identified as Curvularia lunata MLK46 (GenBank accession no. PQ100161). It exhibited maximal productivity at pH 6.5, 30 °C, and incubation for 5 d, with 1% sodium nitrate and 1% galactose as the preferred nitrogen and carbon sources, respectively. Productivity was enhanced by NaCl, CuSO₄, and FeCl₃ supplementation, with a maximum at 0.3 mM, 0.2 mM, and 61.7 mM concentrations, respectively. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) for the purified enzyme through diethylaminoethyl (DEAE)-Sepharose chromatography revealed a prominent band at 71.1 kDa with maximum activity at pH 6 and stability at pH 6–9. Furthermore, it was optimally active at 50 °C and thermally stable at 50–80 °C with a half-life time (T_1/2) of 333.7 min to 80.6 min, respectively. Its activity was also enhanced by many metallic ions, especially Fe³⁺ ions; however, it was inhibited by Hg²⁺ and Ag⁺ ions. The enzyme demonstrated significant degradation of specific substrates such as 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), guaiacol, o-dianisidine, and 2,6-dichlorophenol, with a kinetic efficiency constant which ranged from 40.95 mM⁻¹ s⁻¹ to 238.20 mM⁻¹ s⁻¹. UV spectrophotometry confirmed efficient oxidation peaks by electron transition against guaiacol (at 300 nm), o-dianisidine (at 480 nm), ABTS (at 420 nm), and 2,6-dichlorophenol (at 600 nm). The results collectively demonstrate the potential of laccase from C. lunata MLK46 as a promising agent for the effective biodegradation of several industrial pollutants under extreme conditions.