In Situ Biosynthesis of Reduced Alpha Hematite (α-Fe2O3) Nanoparticles by Stevia Rebaudiana L. Leaf Extract: Insights into Antioxidant, Antimicrobial, and Anticancer Properties

Integration of Antioxidant Activity Assays Data of Stevia Leaf Extracts: A Systematic Review and Meta-Analysis

Stevia rebaudiana Bertoni, a no-calorie natural sweetener, contains a plethora of polyphenols that exert antioxidant properties with potential medicinal significance. Due to the variety of functional groups, polyphenols exhibit varying solubility depending on the nature of the extraction solvents (water, organic, or their mixtures, defined further on as hydroalcoholic extracts). In the present study, we performed a systematic review, following PRISMA guidelines, and meta-analysis, synthesizing all available data from 45 articles encompassing 250 different studies. Our results showed that the total phenolic content (TPC) of hydroalcoholic and aqueous extracts presents higher values (64.77 and 63.73 mg GAE/g) compared to organic extracts (33.39). Total flavonoid content (TFC) was also higher in aqueous and hydroalcoholic extracts; meta-regression analysis revealed that outcomes in different measuring units (mg QE/g, mg CE/g, and mg RUE/g) do not present statistically significant differences and can be synthesized in meta-analysis. Using meta-regression analysis, we showed that outcomes from the chemical-based ABTS, FRAP, and ORAC antioxidant assays for the same extract type can be combined in meta-analysis because they do not differ statistically significantly. Meta-analysis of ABTS, FRAP, and ORAC assays outcomes revealed that the antioxidant activity profile of various extract types follows that of their phenolic and flavonoid content. Using regression meta-analysis, we also presented that outcomes from SOD, CAT, and POX enzymatic antioxidant assays are independent of the assay type (p-value = 0.905) and can be combined. Our study constitutes the first effort to quantitatively and statistically synthesize the research results of individual studies using all methods measuring the antioxidant activity of stevia leaf extracts. Our results, in light of evidence-based practice, uncover the need for a broadly accepted, unified, methodological strategy to perform antioxidant tests, and offer documentation that the use of ethanol:water 1:1 mixtures or pure water can more efficiently extract stevia antioxidant compounds.

Stability, biomechanics and biocompatibility analysis following different preparation strategies of hierarchical zeolite coatings on titanium alloy surfaces

Traditional titanium alloy implant surfaces are inherently smooth and often lack effective osteoinductive properties. To overcome these limitations, coating technologies are frequently employed to enhance the efficiency of bone integration at the implant-host bone interface. Hierarchical zeolites, characterized by their chemical stability, can be applied to 3D-printed porous titanium alloy (pTi) surfaces as coating. The resulting novel implants with a "microporous-mesoporous-macroporous" spatial gradient structure can influence the behavior of adjacent cells; thereby, promoting the integration of bone at the implant interface. Consequently, a thorough exploration of various preparation methods is warranted for hierarchical zeolite coatings with respect to biocompatibility, coating stability, and osteogenesis. In this study, we employed three methods: in situ crystal growth, secondary growth, and layer-by-layer assembly, to construct hierarchical zeolite coatings on pTi, resulting in the development of a gradient structure. The findings of this investigation unequivocally demonstrated that the LBL-coating method consistently produced coatings characterized by superior uniformity, heightened surface roughness, and increased hydrophilicity, as well as increased biomechanical properties. These advantages considerably amplified cell adhesion, spreading, osteogenic differentiation, and mineralization of MC3T3-E1 cells, presenting superior biological functionality when compared to alternative coating methods. The outcomes of this research provide a solid theoretical basis for the clinical translation of hierarchical zeolite coatings in surface modifications for orthopedic implants.

Biogenic silver nanoparticles eradicate of Pseudomonas aeruginosa and Methicillin-resistant Staphylococcus aureus (MRSA) isolated from the sputum of COVID-19 patients

In recent investigations, secondary bacterial infections were found to be strongly related to mortality in COVID-19 patients. In addition, Pseudomonas aeruginosa and Methicillin-resistant Staphylococcus aureus (MRSA) bacteria played an important role in the series of bacterial infections that accompany infection in COVID-19. The objective of the present study was to investigate the ability of biosynthesized silver nanoparticles from strawberries (Fragaria ananassa L.) leaf extract without a chemical catalyst to inhibit Gram-negative P. aeruginosa and Gram-positive Staph aureus isolated from COVID-19 patient’s sputum. A wide range of measurements was performed on the synthesized AgNPs, including UV–vis, SEM, TEM, EDX, DLS, ζ -potential, XRD, and FTIR. UV-Visible spectral showed the absorbance at the wavelength 398 nm with an increase in the color intensity of the mixture after 8 h passed at the time of preparation confirming the high stability of the FA-AgNPs in the dark at room temperature. SEM and TEM measurements confirmed AgNPs with size ranges of ∼40-∼50 nm, whereas the DLS study confirmed their average hydrodynamic size as ∼53 nm. Furthermore, Ag NPs. EDX analysis showed the presence of the following elements: oxygen (40.46%), and silver (59.54%). Biosynthesized FA-AgNPs (ζ = −17.5 ± 3.1 mV) showed concentration-dependent antimicrobial activity for 48 h in both pathogenic strains. MTT tests showed concentration-dependent and line-specific effects of FA-AgNPs on cancer MCF-7 and normal liver WRL-68 cell cultures. According to the results, synthetic FA-AgNPs obtained through an environmentally friendly biological process are inexpensive and may inhibit the growth of bacteria isolated from COVID-19 patients.

Removal of hydrocarbons and heavy metals from petroleum water by modern green nanotechnology methods

Considered heavy metals, such as As(III), Bi(II), Cd(II), Cr(VI), Mn(II), Mo(II), Ni(II), Pb(II), Sb(III), Se(-II), Zn(II), and contaminating chemical compounds (monocyclic aromatic hydrocarbons such as phenolic or polycyclic derivatives) in wastewater (petrochemical industries: oil and gas production plants) are currently a major concern in environmental toxicology due to their toxic effects on aquatic and terrestrial life. In order to maintain biodiversity, hydrosphere ecosystems, and people, it is crucial to remove these heavy metals and polluting chemical compounds from the watery environment. In this study, different Nanoparticles (α-Fe₂O₃, CuO, and ZnO) were synthesized by green synthesis method using Portulaca oleracea leaf extract and characterized by UV-Vis spectrophotometers, FTIR spectroscopy, X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS) techniques in order to investigate morphology, composition, and crystalline structure of NPs, these were then used as adsorbent for the removal of As(III), Bi(II), Cd(II), Cr(VI), Mn(II), Mo(II), Ni(II), Pb(II), Sb(III), Se(-II), and Zn(II) from wastewater, and removal efficiencies of were obtained 100% under optimal conditions.

Novel Copper Oxide Bio-Nanocrystals to Target Outer Membrane Lectin of Vancomycin-Resistant Enterococcus faecium (VREfm): In Silico, Bioavailability, Antimicrobial, and Anticancer Potential

In present study, we used Olea europaea leaf extract to biosynthesize in situ Copper Oxide nanocrystals (CuO @OVLe NCs) with powerful antibacterial and anti-cancer capabilities. Physio-chemical analyses, such as UV/Vis, FTIR, XRD, EDX, SEM, and TEM, were applied to characterize CuO @OVLe NCs. The UV/Vis spectrum demonstrated a strong peak at 345 nm. Furthermore, FTIR, XRD, and EDX validated the coating operation's contact with colloidal CuO @OVLe NCs. According to TEM and SEM analyses, CuO @OVLe NCs exhibited a spherical shape and uniform distribution of size with aggregation, for an average size of ~75 nm. The nanoparticles demonstrated a considerable antibacterial effect against E. faecium bacterial growth, as well as an increased inhibition rate in a dose-dependent manner on the MCF-7, PC3, and HpeG2 cancer cell lines and a decreased inhibition rate on WRL-68. Molecular docking and MD simulation were used to demonstrate the high binding affinity of a ligand (Oleuropein) toward the lectin receptor complex of the outer membrane to vancomycin-resistant E. faecium (VREfm) via amino acids (Leu 195, Thr 288, His 165, and Ser 196). Hence, our results expand the accessibility of OVLe's bioactive components as a promising natural source for the manufacture of physiologically active components and the creation of green biosynthesis of metal nanocrystals.