Phyto-fabrication, purification, characterisation, optimisation, and biological competence of nano-silver

Evaluating the Effect of pH, Temperature and Concentration on Antioxidant and Antibacterial Potential of Spectroscopically, Spectrophotometrically and Microscopically Characterized Mentha Spicata Capped Silver Nanoparticles

The use of traditional plants has been tremendously increased due to their higher biological impact, minimal side effects, and comparatively low cost. Moreover, the emergence of antibacterial resistance is also shifting the scientific community to reconsider herbal remedies which provide relatively safer, cheap and biologically tolerable solutions. The present research was designed to fabricate the Mentha spicata conjugated silver nanoparticles (Me-AgNPs). Furthermore, the assessment of the bactericidal potential of Me-AgNPs against various bacterial strains was another motive behind this study. Fabricated NPs were characterized with the help of the UV-Visible spectrophotometric analysis, Fourier transform infrared spectroscopy (FTIR) and Scanning electron microscopy (SEM). Me-AgNPs showed a significant zone of inhibition (23 ± 0.2 mm) at 8 mg/mL against Staphylococcus aureus and a 4.0 ± 0.2 mm zone of growth inhibition at 2 mg/mL against Aeromonas veronii. The stability of Me-AgNPs was assessed at various pH (4, 7 and 11) and temperatures (25 °C, 4 °C, 37 °C, 75 °C). The significant zones of inhibition (11.3 ± 0.3 mm, 8.3 ± 0.3mm, 14.3 ± 0.3 mm, and 7.6 ± 0.2 mm) were observed at pH 11 against Escherichia coli, Staphylococcus aureus, Bacillus subtilis, and Klebsiella pneumoniae, respectively. Growth inhibition zones (14.0 ± 0.5 mm and 13.0 ± 0.5 mm) were also determined against B. subtilis and S. aureus at 25 °C. DPPH bioassay was conducted to find the antioxidant properties of Me-AgNPs. The highest (38.66 ± 0.2%) free radical scavenging activity was shown by Me-AgNPs at 4 mg/mL. Present study results concluded that biogenic Me-AgNPs have bactericidal as well as anti-oxidative potential. Moreover, these green synthesized Me-AgNPs could maintain their potency and stability at a wide range of pH and temperature.

Field emission scanning electron microscopic, X-ray diffraction and ultraviolet spectroscopic analysis of Terminalia bellerica based silver nanoparticles and evaluation of their antioxidant, catalytic and antibacterial activity

In recent years, scientists have come up with ways to make nanoparticles that are inexpensive and good for the environment. Terminalia bellerica-based silver nanoparticles (TBAgNPs) were made in this study using methanol extract from T. bellerica fruits. This method was quick, economical, and good for the environment. The biosynthesized TBAgNPs were used as antioxidants, antibacterial agents, and anti-catalytic agents. Analytical techniques like XRD, FESEM, and UV-Vis were used to find out more about the spherical TBAgNPs that were made. Also, Cefotaxime-resistant bacteria found in hospitals were used to test how well the TBAgNPs killed bacteria. With the Bauer-agar Kirby's gel diffusion and Mueller-Hinton broth methods, the ability of the synthesized TBAgNPs to stop bacterial growth was tested. After the TBAgNPs were studied, it was found that the average size of their crystals was between 10 and 25 nm. 2,2-Diphenyl-1-picrylhydrazyl (DPPH) reducing tests showed that these AgNPs could act as antioxidants, and TBAgNPs (%inhibition = 20.90% to 94.94%) were better antioxidant than ascorbic acid (%inhibition = 13.80% to 86.10%) and extract (%inhibition = 16.90% to 80.50%). The reduction of methylene blue (MB) to leucomethylene blue (LMB) with sodium borohydride (NaBH₄) was used as a model to test the catalytic potential of TBAgNPs. On UV spectroscopic analysis at room temperature, TBAgNPs at different concentrations were able to reduce methylene blue effectively. For Escherichia coli and Klebsiella pneumoniae, the minimum inhibitory concentration (MIC) for TBAgNPs was 0.625 μg/mL and 1.25 μg/mL, respectively. Based on these results, silver nanoparticles made with Terminalia bellerica extract may have much biological importance and could be used in making useful therapeutic applications.

Evaluation of the Wound Healing Potential of Cynara humilis Extracts in the Treatment of Skin Burns

Cynara humilis is traditionally used to treat skin burns and microbial infections. However, experimental studies on this plant are rare. Furthermore, the aim of this study was to investigate the effects of Cynara humilis, a Moroccan herbal remedy, on the healing of deep second-degree burns in rats with a silver sulfadiazine group. This research was also carried out to confirm if C. humilis had antibacterial capabilities. Under typical burn procedures, each rat received a deep second-degree burn on the upper back. The burns were treated regularly with control groups (control and control VH), silver sulfadiazine (SDD) in group 3, C. humilis ethanolic extract (CHEE) in group 4, and C. humilis aqueous extract (CHAE) in group 5. Throughout the treatment, digital photography was used to measure rat responses to the treatment until day 18. After the scar biopsy at the end of the study, histological parameters (inflammatory cells, collagen, epithelialization, fibrosis, and granulation tissue) were assessed. Using the well technique, the antibacterial activity of the extracts was tested against Staphylococcus aureus CIP 483, Bacillus subtilis CIP 5262, Escherichia coli CIP 53126, Pseudomonas aeruginosa CIP 82118, and Salmonella enterica CIP 8039, and the results showed important activities of the ethanolic and aqueous extracts against the five species tested with MICs of 2 and 4 mg/mL, respectively. In the aqueous extract group, the wound healed faster. In addition, the healing rate in the C. humilis extracts (CHEA and CHEE) group was faster than in the silver sulfadiazine and control groups. In the C. humilis group, maximum wound surface recovery was observed at the same time, as it was not noted in the silver sulfadiazine group. Pathologically, epithelialization was more marked in wounds treated with C. humilis extracts (CHE). Angiogenesis and inflammatory cells were considerably lower in the CHE group than in the silver and other control groups. However, elastic fibers were considerable in the CHE-treated group. In histological examination, the C. humilis group had a low incidence of angiogenesis and inflammation, indicating that this group had less wound scarring. Collagen and burn wound healing were both faster in the C. humilis group. The findings of this study suggest that C. humilis, as indicated by traditional medicine, is a promising natural source for the management of wound healing.

Saussurea costus extract as bio mediator in synthesis iron oxide nanoparticles (IONPs) and their antimicrobial ability

Saussurea costus is from medicinal plants and have therapeutic properties that were recorded in a variety of medical functions. The usage of biomaterials in the synthesis of nanoparticles is an essential strategy in green nanotechnology. Iron oxide nanoparticles (IONPs) were composed in the stage of (2:1, FeCl2: FeCl3) solution by using the aqueous extract of Saussurea costus peel in an eco-friendly method to evaluate their antimicrobial property. The properties of the obtained IONPs were evaluated using a scanning (SEM) and transmission (TEM) electron microscope. The mean size of IONPs discovered by Zetasizer varies between 100 and 300 nm, with a mean particle size of 295 nm. The morphology of IONPs (γ-Fe2O3) was determined to be nearly spherical and prismatic-curved. Moreover, the antimicrobial property of IONPs was assessed with nine pathogenic microbes, revealing that the nanoparticles have antimicrobial activities with Pseudomonas aeruginosa, Escherichia coli, Shigella sp., Staphylococcus sp. and Aspergillus niger, with possible applications in the therapeutic and biomedical fields.

Biogenic Synthesis of Silver Nanoparticles Using Rhazya stricta Extracts and Evaluation of Its Biological Activities

Rhazya stricta is a well‐known medicinal plant and source of numerous potential secondary metabolites including steroids, alkaloids, and tannins. R. stricta possesses multimedical applications and used for curing of various diseases such as inflammation, diabetes, sore throat, infectious, helminthiasis, arthritis, and cancer. The current investigation deals with synthesizing AgNPs using aqueous and ethanol extracts of R. stricta. The synthesized R. stricta‐AgNPs were characterized through UV‐visible, Fourier transform infrared (FTIR), and atomic force microscopy (AFM) methods. The UV‐visible analysis exhibited a characteristic absorption λmax at 475 nm in R. stricta ethanol AgNPs while this peak was absent in R. stricta aqueous crude extract. The thermal stability of R. stricta‐AgNPs demonstrated that by increasing the reduction time and temperature, the absorption of AgNPs also increased, leading to more stable NPs formation. The FTIR spectra showed a broad peak at 450‐550 cm-1 that confirmed the occurrence of AgNPs of R. stricta. The AFM study of the synthesized AgNPs revealed the spherical shape and size ranging from 30 nm to 90 nm. In antioxidant and antibacterial study, the R. stricta‐AgNPs exhibited good antioxidant activity (87.94% and 88.37%) than the ethanol crude extract (50.00% and 56.81%) at 100 μg/mL using DPPH assay. Maximum antibacterial activity was recorded against Gram‐positive bacteria (Staphylococcus aureus), which was 15 and 0 mm, while against Gram‐negative bacteria (Klebsiella pneumonia) was found to be 16 and 14 mm, respectively, whereas against Bacillus subtills, a poor activity was recorded as 14 for extract and 0 mm for AgNPs, respectively. In the acetic acid‐induced writhing model, the percent effect of extract (100 mg/kg) and AgNPs (15 mg/kg) was 79.98 and 83.23, respectively. The maximum muscle coordination effect of extracts in the inclined plan and traction test was 44% and 38% at higher doses. A mild sedative effect was also recorded against extract and AgNPs. The significant (p < 0.05) effect of extract was noted at 100 mg/kg while AgNPs was more significant (p < 0.01) at the tested dose of 15 mg/kg. These findings have concluded that R. stricta‐AgNPs is an effective bioreductant of AgNPs synthesis and exhibit several applications in distinctive biomedical and pharmaceutical industries.

Heavy Metal Contamination of Natural Foods Is a Serious Health Issue: A Review

Heavy metals play an important role in the homeostasis of living cells. However, these elements induce several adverse environmental effects and toxicities, and therefore seriously affect living cells and organisms. In recent years, some heavy metal pollutants have been reported to cause harmful effects on crop quality, and thus affect both food security and human health. For example, chromium, cadmium, copper, lead, and mercury were detected in natural foods. Evidence suggests that these elements are environmental contaminants in natural foods. Consequently, this review highlights the risks of heavy metal contamination of the soil and food crops, and their impact on human health. The data were retrieved from different databases such as Science Direct, PubMed, Google scholar, and the Directory of Open Access Journals. Results show that vegetable and fruit crops grown in polluted soil accumulate higher levels of heavy metals than crops grown in unpolluted soil. Moreover, heavy metals in water, air, and soil can reduce the benefits of eating fruits and vegetables. A healthy diet requires a rational consumption of foods. Physical, chemical, and biological processes have been developed to reduce heavy metal concentration and bioavailability to reduce heavy metal aggregation in the ecosystem. However, mechanisms by which these heavy metals exhibit their action on human health are not well elucidated. In addition, the positive and negative effects of heavy metals are not very well established, suggesting the need for further investigation.

Do Iron Oxide Nanoparticles Have Significant Antibacterial Properties?

The use of metal oxide nanoparticles is one of the promising ways for overcoming antibiotic resistance in bacteria. Iron oxide nanoparticles (IONPs) have found wide applications in different fields of biomedicine. Several studies have suggested using the antimicrobial potential of IONPs. Iron is one of the key microelements and plays an important role in the function of living systems of different hierarchies. Iron abundance and its physiological functions bring into question the ability of iron compounds at the same concentrations, on the one hand, to inhibit the microbial growth and, on the other hand, to positively affect mammalian cells. At present, multiple studies have been published that show the antimicrobial effect of IONPs against Gram-negative and Gram-positive bacteria and fungi. Several studies have established that IONPs have a low toxicity to eukaryotic cells. It gives hope that IONPs can be considered potential antimicrobial agents of the new generation that combine antimicrobial action and high biocompatibility with the human body. This review is intended to inform readers about the available data on the antimicrobial properties of IONPs, a range of susceptible bacteria, mechanisms of the antibacterial action, dependence of the antibacterial action of IONPs on the method for synthesis, and the biocompatibility of IONPs with eukaryotic cells and tissues.

Do Iron Oxide Nanoparticles Have Significant Antibacterial Properties?

The use of metal oxide nanoparticles is one of the promising ways for overcoming antibiotic resistance in bacteria. Iron oxide nanoparticles (IONPs) have found wide applications in different fields of biomedicine. Several studies have suggested using the antimicrobial potential of IONPs. Iron is one of the key microelements and plays an important role in the function of living systems of different hierarchies. Iron abundance and its physiological functions bring into question the ability of iron compounds at the same concentrations, on the one hand, to inhibit the microbial growth and, on the other hand, to positively affect mammalian cells. At present, multiple studies have been published that show the antimicrobial effect of IONPs against Gram-negative and Gram-positive bacteria and fungi. Several studies have established that IONPs have a low toxicity to eukaryotic cells. It gives hope that IONPs can be considered potential antimicrobial agents of the new generation that combine antimicrobial action and high biocompatibility with the human body. This review is intended to inform readers about the available data on the antimicrobial properties of IONPs, a range of susceptible bacteria, mechanisms of the antibacterial action, dependence of the antibacterial action of IONPs on the method for synthesis, and the biocompatibility of IONPs with eukaryotic cells and tissues.