Biosynthesis, characterization and anthelmintic activity of silver nanoparticles of Clerodendrum infortunatum isolate

Antibacterial and antibiofilm efficacy of Solanum lasiocarpum root extract synthesized silver/silver chloride nanoparticles against Staphylococcus haemolyticus associated with bovine mastitis

Staphylococcus haemolyticus is a cause of bovine mastitis, leading to inflammation in the mammary gland. This bacterial infection adversely affects animal health, reducing milk quality and yield. Its emergence has been widely reported, representing a significant economic loss for dairy farms. Interestingly, S. haemolyticus exhibits higher levels of antimicrobial resistance than other coagulase-negative Staphylococci. In this study, we synthesized silver/silver chloride nanoparticles (Ag/AgCl-NPs) using Solanum lasiocarpum root extract and evaluated their antibacterial and antibiofilm activities against S. haemolyticus. The formation of the Ag/AgCl-NPs was confirmed using UV-visible spectroscopy, which revealed maximum absorption at 419 nm. X-ray diffraction (XRD) analysis demonstrated the crystalline nature of the Ag/AgCl-NPs, exhibiting a face-centered cubic lattice. Fourier transform infrared (FT-IR) spectroscopy elucidated the functional groups potentially involved in the Ag/AgCl-NPs synthesis. Transmission electron microscopy (TEM) analysis revealed that the average particle size of the Ag/AgCl-NPs was 10 nm. Antimicrobial activity results indicated that the minimum inhibitory concentration (MIC) and maximum bactericidal concentration (MBC) of the Ag/AgCl-NPs treatment were 7.82-15.63 μg/mL towards S. haemolyticus. Morphological changes in bacterial cells treated with the Ag/AgCl-NPs were observed under scanning electron microscopy (SEM). The Ag/AgCl-NPs reduced both the biomass of biofilm formation and preformed biofilm by approximately 20.24-94.66 % and 13.67-88.48 %. Bacterial viability within biofilm formation and preformed biofilm was reduced by approximately 21.56-77.54 % and 18.9-71.48 %, respectively. This study provides evidence of the potential of the synthesized Ag/AgCl-NPs as an antibacterial and antibiofilm agent against S. haemolyticus.

Silversol® (a Colloidal Nanosilver Formulation) Inhibits Growth of Antibiotic-Resistant Staphylococcus aureus by Disrupting Its Physiology in Multiple Ways

Antibiotic-resistant strains of Staphylococcus aureus are being viewed as a serious threat by various public health agencies. Identifying novel targets in this important pathogen is crucial to the development of new effective antibacterial formulations. We investigated the antibacterial effect of a colloidal nanosilver formulation, Silversol®, against an antibiotic-resistant strain of S. aureus using appropriate in vitro assays. Moreover, we deciphered the molecular mechanisms underlying this formulation's anti-S. aureus activity using whole transcriptome analysis. Lower concentrations of the test formulation exerted a bacteriostatic effect against this pathogen, and higher concentrations exerted a bactericidal effect. Silversol® at sub-lethal concentration was found to disturb multiple physiological traits of S. aureus such as growth, antibiotic susceptibility, membrane permeability, efflux, protein synthesis and export, biofilm and exopolysaccharide production, etc. Transcriptome data revealed that the genes coding for transcriptional regulators, efflux machinery, transferases, β-lactam resistance, oxidoreductases, metal homeostasis, virulence factors, and arginine biosynthesis are expressed differently under the influence of the test formulation. Genes (argG and argH) involved in arginine biosynthesis emerged among the major targets of Silversol®'s antibacterial activity against S. aureus.

Untargeted metabolomics and molecular docking studies on green silver nanoparticles synthesized by Sarocladium subulatum: Exploring antibacterial and antioxidant properties

The biological synthesis of silver nanoparticles (Ag-NPs) with fungi has shown promising results in antibacterial and antioxidant properties. Fungi generate metabolites (both primary and secondary) and proteins, which aid in the formation of metal nanoparticles as reducing or capping agents. While several studies have been conducted on the biological production of Ag-NPs, the exact mechanisms still need to be clarified. In this study, Ag-NPs are synthesized greenly using an unstudied fungal strain, Sarocladium subulatum AS4D. Three silver salts were used to synthesize the Ag-NPs for the first time, optimized using a cell-free extract (CFE) strategy. Additionally, these NPs were assessed for their antimicrobial and antioxidant properties. Various spectroscopic and microscopy techniques were utilized to confirm Ag-NP formation and analyze their morphology, crystalline properties, functional groups, size, stability, and concentrations. Untargeted metabolomics and proteome disruption were employed to explore the synthesis mechanism. Computational tools were applied to predict metabolite toxicity and antibacterial activity. The study identified 40 fungal metabolites capable of reducing silver ions, with COOH and OH functional groups playing a pivotal role. The silver salt type impacted the NPs' size and stability, with sizes ranging from 40 to 52 nm and zeta potentials from -0.9 to -30.4 mV. Proteome disruption affected size and stability but not shape. Biosynthesized Ag-NPs using protein-free extracts ranged from 55 to 62 nm, and zeta potentials varied from -18 to -27 mV. Molecular docking studies and PASS results found no role for the metabolome in antibacterial activity. This suggests the antibacterial activity comes from Ag-NPs, not capping or reducing agents. Overall, the research affirmed the vital role of specific reducing metabolites in the biosynthesis of Ag-NPs, while proteins derived from biological extracts were found to solely affect their size and stability.

Long-Lasting Silver Nanoparticles Synthesized with Tagetes erecta and Their Antibacterial Activity against Erwinia amylovora, a Serious Rosaceous Pathogen

A rapid, eco-friendly, and simple method for the synthesis of long-lasting (2 years) silver nanoparticles (AgNPs) is reported using aqueous leaf and petal extracts of Tagetes erecta L. The particles were characterized using UV-Visible spectrophotometry and the analytical and crystallographic techniques of transmission electron microscopy (TEM). The longevity of the AgNPs was studied using UV-Vis and high-resolution TEM. The antibacterial activity of the particles against Erwinia amylovora was evaluated using the Kirby-Bauer disk diffusion method. The results were analyzed using ANOVA and Tukey's test (p ≤ 0.05). Both the leaf and petal extracts produced AgNPs, but the leaf extract (1 mL) was long-lasting and quasi-spherical (17.64 ± 8.87 nm), with an absorbance of UV-Vis λmax 433 and a crystalline structure (fcc, 111). Phenols, flavonoids, tannins, and terpenoids which are associated with -OH, C=O, and C=C were identified in the extracts and could act as reducing and stabilizing agents. The best antibacterial activity was obtained with a nanoparticle concentration of 50 mg AgNPs L-1. The main contribution of the present research is to present a sustainable method for producing nanoparticles which are stable for 2 years and with antibacterial activity against E. amylovora, one of most threatening pathogens to pear and apple productions.

Nematocidal activity of chitosan nanoparticles conjugated with albendazole against the enteral and parenteral phases of trichinosis in experimentally infected mice

Trichinosis is a serious parasitic zoonotic disease caused mainly by Trichinella spiralis. The used drugs for treatment of trichinosis showed limited bioavailability and high degree of resistance. Moreover, they have a very poor effect in treatment of encysted larvae. Therefore, there is a need for development of new agents which help in improving the bioavailability of the used drugs and enable them to reach different tissues. This study was designed to assess the use of chitosan nanoparticles (CSNPs) in conjugation with full and half dose albendazole (ABZ) in treatment of intestinal and muscular trichinosis. Albino mice (84 mice) were used to evaluate the efficacy of drugs and divided into seven groups; I: control, II: ABZ (50 mg/kg) treated, III: ABZ (25 mg/kg) treated, IV: ABZ (50 mg/kg) conjugated CSNPs treated, V: ABZ (25 mg/kg) conjugated CSNPs treated, VI: CS treated and VII: CSNPs treated. Parasitological and histopathological examinations were used to evaluate the therapeutic efficacy of the used drugs. Results showed significant reduction of adult Trichinella extracted from intestine of all ABZ treated groups either conjugated or not with the highest reduction rate in group IV followed by group V with percentage of reduction of 99.33% and 98.11%, respectively and marked improvement of histopathological examination. Also, results showed significant reduction of Trichinella larvae extracted from muscles of group IV, V and VII with the highest reduction rate in group IV with percentage of reduction of 100% in muscle larvae and marked improvement of histopathological examination. It was concluded that albendazole full dose conjugated chitosan nanoparticles can be a good candidate drug for treating both intestinal and muscular trichinosis.

Biogenic silver nanoparticles' antibacterial activity and cytotoxicity on human hepatocarcinoma cells (Huh-7)

Exploring diverse synthetic pathways for nanomaterial synthesis has emerged as a promising direction. For example, silver nanoparticles (AgNPs) are synthesized using different approaches yielding nanomaterials with distinct morphological, physical and biological properties. Hence, the present study reports the biogenic synthesis of silver nanoparticles using the aqueous secretome of the fungus Fusarium oxysporum f. sp. cubense (AgNP@Fo) and orange peel extract (AgNP@OR). The physical and morphological properties of synthesized nanoparticles were similar, with AgNP@Fo measuring 56.43 ± 19.18 nm and AgNP@OR measuring 39.97 ± 19.72 nm in size. The zeta potentials for the nanoparticles were low, -26.8 ± 7.55 and -26.2 ± 2.87 mV for AgNP@Fo and AgNP@OR, respectively, demonstrating a similar negative charge. The spherical morphologies of both nanoparticles were evidenced by Scanning Transmission Electron Microscopy (STEM) and Atomic Force Microscopy (AFM). However, despite their similar physical and morphological properties, AgNPs demonstrated different bioactivities. We evaluated and compared the antimicrobial efficacy of these nanoparticles against a range of bacteria, such as Staphylococcus aureus, Enterococcus faecalis, Pseudomonas aeruginosa, and Escherichia coli. The AgNP@Fo showed Minimum Inhibitory Concentration (MIC) values ranging from 0.84 to 1.68 μg mL-1 and were around ten times more potent compared to AgNP@OR. The anticancer activities of both nanoparticles were investigated using human hepatocarcinoma cells (Huh-7), where AgNP@Fo exhibited around 20 times higher cytotoxicity than AgNP@OR with an IC50 value of 0.545 μmol L-1. Anticancer effects were demonstrated by the MTT, confirmed by the calcein-AM assay and fluorescence imaging. This study establishes solid groundwork for future exploration of molecular interactions of nanoparticles synthesized through distinct biosynthetic routes, particularly within bacterial and cancerous cell environments.

Thespesia lampas mediated green synthesis of silver and gold nanoparticles for enhanced biological applications

The present study investigated the synthesis and biological applications of green, economical, and multifunctional silver and gold nanoparticles (TSAgNPs and TSAuNPs) using the ethnomedical important medicinal plant Thespesia lampas for biological activities. Relatively higher levels of antioxidant components were measured in T. lampas compared to the well-known Adhatoda vasica, and Diplocyclos palmatus suggested the potential of T. lampas for the study. Synthesized TSAgNPs and TSAuNPs were characterized through UV-Vis, XRD, SEM-EDS, HR-TEM, SAED, and FTIR techniques. SEM revealed that TSAgNPs and TSAuNPs were predominantly spherical in shape with 19 ± 7.3 and 43 ± 6.3 nm crystal sizes. The sizes of TSAgNPs and TSAuNPs were found to be12 ± 4.8 and 45 ± 2.9 nm, respectively, according to TEM measurements. The FTIR and phytochemical analyses revealed that the polyphenols and proteins present in T. lampas may act as bio-reducing and stabilizing agents for the synthesis. Synthesized NPs exhibited enhanced scavenging properties for ABTS and DPPH radicals. TSAgNPs and TSAuNPs were able to protect DNA nicking up to 13.48% and 15.38%, respectively, from oxidative stress. TSAgNPs possessed efficient antibacterial activities in a concentration-dependent manner against human pathogenic bacteria, such as E. coli, B. subtilis, P. vulgaris, and S. typhi. Furthermore, TSAgNPs and TSAuNPs showed significant cytotoxicity against FaDu HNSCC grown in 2D at 50 and 100 μg mL-1. Tumor inhibitory effects on FaDu-derived spheroid were significant for TSAgNPs > TSAuNPs at 100 μg mL-1 in 3D conditions. Dead cells were highest largely for TSAgNPs (76.65% ± 1.76%), while TSAuNPs were non-significant, and Saq was ineffectively compared with the control. However, the diameter of the spheroid drastically reduced for TSAgNPs (3.94 folds) followed by TSAuNPs (2.58 folds), Saq (1.94 folds), and cisplatin (1.83 folds) at 100 μg mL-1. The findings of the study suggested the bio-competence of TSAgNPs and TSAuNPs as multi-responsive agents for antioxidants, DNA protection, antibacterial, and anti-tumor activities to provide a better comprehension of the role of phytogenic nanoparticles in healthcare systems.

Gallic acid and Catechin induce morphological alterations on the zoonotic parasite Hymenolepis diminuta

Tapeworm infections cause insidious and irreversible effects in the infected individuals and some of them have already shown resistance to available drugs. A search for alternative treatment is urgently required. Phenolic compounds are amongst the most researched natural substances for their medicinal use. The present study aims to determine anthelmintic efficacy of two polyphenols Gallic acid and Catechin against the zoonotic rat tapeworm Hymenolepis diminuta. Both compounds are potent anti-oxidants and play major roles in combating pathogens, while their anthelmintic property according to our knowledge is yet to be explored. The parasite model H. diminuta was procured from intestine of infected rats raised in our laboratory. Two sets of parasites were treated in vitro with 5, 10, 20 and 40 mg/ml concentrations of each Gallic Acid and Catechin separately, another set of parasites were treated with standard dose of Praziquantel in RPMI 1640, while still another set of worms were kept in RPMI 1640 at 37 ± 10C with 1% Dimethyl sulfoxide as control. Motility and structural alterations were the parameters assessed for anthelmintic efficacy of the compounds. After paralysis the worms were processed for morphological, histological, and ultrastructural study and observed under light and electron microscope. Dose-dependent efficacy was observed in both compounds. Shrinkage of suckers, deformed proglottids and architectural alteration of the tegument were observed throughout the body of treated parasites compared to control. Although in terms of time taken for paralysis and mortality Gallic acid was more effective than Catechin, the degree of morphological aberrations caused were almost similar, except histological alteration was more in Catechin treated worms than in Gallic acid. Nevertheless, both Gallic acid and Catechin are suggested to possess anthelmintic efficacy besides other health benefits but extended studies are required to compare their efficacy.

Anthelmintic efficacy of Holarrhena pubescens against Raillietina spp. of domestic fowl through ultrastructural, histochemical, biochemical and GLCM analysis

Globally, traditional knowledge systems are a powerhouse of information which can revolutionise the world, if decoded accurately and logically. Plant-based ethno-traditional and folklore curatives/medicines has a firm basis in the psyche of the common masses of West Bengal and Holarrhena pubescens is a representative example of it. This article communication on depicting the anthelmintic efficacy of ethanolic extract and Ethyl acetate fraction of the stem bark of Holarrhena pubescens against the cestode Raillietina spp. through efficacy studies, ultra-structural observations, histochemical and biochemical analysis on some tegumental enzymes i.e., Acid Phosphatase (AcPase), Alkaline Phosphatase (AlkPase), Adenosine Triphosphatase (ATPase) and 5'-Nucleotidase (5'-Nu) along with Gray Level Co-occurrence Matrix (GLCM) analysis of histochemical study. Praziquantel was used as the reference drug. Investigations revealed 10mg/ml dosage of crude extract was the most efficacious dose and amongst the fractions the ethyl acetate fraction showed the most anthelmintic property. Ultrastructural studies through Scanning Electron Microscope (SEM) and Transmission Electron Microscope (TEM) clearly depicted the damage in head, sucker, proglottids, proximal and distal cytoplasm (DC), microtriches (MT), basal lamina (BL), nuclear membrane (NM), and, nucleolus (NL) in the treated worms. Histochemical studies revealed decrease in staining intensity for all the tegumental enzymes in the treated worms compared to control. The GLCM analysis strongly supported the result of histochemical studies. Biochemical studies revealed marked reduction in enzyme activity in the treated worms with maximum reduction in the activity of 5'- Nu (77.8%) followed by ATPase (63.17%).