Green synthesis of non-toxic silver nanoparticles using Salvia tebesana Bunge extract: Optimization, cytotoxicity, and antibacterial activities

The remarkable antibacterial activity and potential biomedical applications of silver nanoparticles (AgNPs) synthesized through eco-friendly approaches have garnered significant attention in recent years. This research aimed to introduce a green synthesis method for AgNPs using Salvia tebesana (S. tebesana) Bunge extract and to investigate their properties, antibacterial activities, and cytotoxicity effects. The fabricated AgNPs were analyzed with various analyses, including UV–Vis, DLS, XRD, FT-IR, and TEM analysis. The broth microdilution assay was applied to measure the Minimum Inhibitory Concentrations (MIC) of chemical AgNPs, biosynthesized AgNPs, and S. tebesana Bunge leaves extract alone against selected standard bacteria strains. The biosynthesized AgNPs displayed a surface plasmon resonance peak at approximately 415 nm, and the AgNPs synthesized using S. tebesana Bunge extract had a spherical configuration with an average size in the range of 10–15 nm. Biosynthesized nanoparticles showed a noteworthy antibacterial activity compared to chemical nanoparticles, particularly against P. aeruginosa, with the highest antibacterial activity reported at a MIC value of 39.06 μg/mL. AgNPs synthesized using S. tebesana Bunge extract demonstrated a significant decrease in fibroblast cell viability, but only when the concentration reached 2 mg/mL. The findings demonstrate that S. tebesana Bunge leaves extract enhances the antibacterial properties of AgNPs, and also represents an appropriate and biocompatible option for the synthesis of these nanoparticles. Our research highlights the potential of employing bio-safe and eco-friendly AgNPs synthesized in the presence of S. tebesana Bunge extract, which possess remarkable antibacterial properties, for various biomedical applications

Preliminary in vitro assessment of the potential toxicity and antioxidant activity of Ceiba speciosa (A. St.-Hill) Ravenna (Paineira)

ABSTRACT The bark tea of Ceiba speciosa, a tropical tree of the Malvaceae family, is used in the Northwestern Region of Rio Grande do Sul state, Brazil, to reduce blood cholesterol levels. However, there are no scientific data on the efficacy and safety of this plant. The aim of the present study was to evaluate the in vitro antioxidant and toxic potential of bark extracts of C. speciosa. We performed a preliminary phytochemical analysis by high-performance liquid chromatography-diode array detection (HPLC-DAD) and evaluated the oxidative damage to proteins and lipids, the radical scavenging effect, and genotoxicity of the lyophilized aqueous extract (LAECs) and the precipitate obtained from the raw ethanol extract (Cs1). The phytochemical profile demonstrated the presence of phenolic and flavonoid compounds. The LAECs and Cs1 prevented damage to lipids and proteins at concentrations of 50 and 10 µg/mL. They also showed a scavenging effect on 2,2-diphenyl-1-pricril-hydrazyl (DPPH) radicals in a concentration-dependent manner. Furthermore, no genotoxic effect was observed at concentrations of 10, 5 and 2 µg/mL in the Comet assay. The present study is the first evaluation regarding the characterization of C. speciosa and its safety, and the results demonstrate its antioxidant potential and suggest that its therapeutic use may be relatively safe

Abietane-type diterpenoids from the roots of Salvia tebesana

Background and objectives: The genus Salvia is one of the largest genera in the family Lamiaceae and represents approximately 1000 species displaying a remarkable diversity.Salvia tebesana Bunge(Lamiaceae) is an endemic medicinal species that grows wild in center of Iran which is locally named “Maryamgoli Tabasi”. Methods: The dried roots (2 kg) were perculated with MeOH at room temperature. Methanol extract was further fractionated to give four different fractions [n-hexane, dichloromethane (CH2Cl2), ethyl acetate (EtOAc) and water (H2O)]. In the next step, to afford the major bioactive compound(s) of the plant, the EtOAC extract was further sub-fractionated by silica gel column chromatography using a mixture of petroleum ether/ethyl acetate with increasing polarity. The different fractions were purified by reversed-phase semi-preparative HPLC. Results: From the ethyl acetate extract, two diterpene quinones with rearranged abietane skeletons, aegyptinones A and B were isolated and their structures were mainly elucidated by 1D and 2D NMR and mass spectroscopy. Conclusion: These compounds have been reported for the first time from this plant

One for All and All for One! Increased Plant Heavy Metal Tolerance by Growth-Promoting Microbes: A Metabolomics Standpoint

Increasing urbanization and industrialization cause the unavoidable mass release of pollutants in the environment. Nanoparticles and heavy metals are among the most threatening agents affecting ecosystems. Agriculture is severely affected by these eco-toxicants: crop productivity dramatically drops, since plant growth and development are negatively impacted. Arable lands are sinks accumulating pollutants which establish physic-chemical associations with soil particles: this leads to changes in the properties of soils, namely texture and, ultimately, alters the availability of nutrients. Green technologies in agriculture rely on the use of environmental-friendly alternatives to boost crop productivity under exogenous constraints. In this context, the use of beneficial plant growth-promoting microbes (PGPMs) is seen as a promising strategy to protect plants against the stress triggered by eco-toxicants. A strong body of evidence in the literature has shown that some PGPMs (e.g. local strains) are natural heavy metal accumulators and may also influence the metabolome of the plants they associate with. Therefore, their action is both direct and indirect. An example of the former is the secretion of extracellular polysaccharides (EPS) which function as a mechanical barrier and entrap heavy metals; an indirect effect is the priming of defence responses leading to the synthesis of specific classes of plant secondary metabolites. In this chapter, the accent will be put on the analytical power of metabolomics in conjunction with meta-metabolomics (i.e. the analysis of the metabolome of an entire community of microbes associating with different plant organs). The ultimate goal is to unravel the mechanisms responsible for the increased heavy metal tolerance in crops establishing an interaction with PGPMs. We will end our survey with some perspectives on innovative strategies in agrobiotechnology valorising PGPMs in conjunction with fertilization using beneficial elements like silicon (Si) and capable of providing sustainable solutions facing the ever-increasing release of pollutants in the environment