Use of A Hydroalcoholic Extract of Moringa oleifera Leaves for the Green Synthesis of Bismuth Nanoparticles and Evaluation of Their Anti-Microbial and Antioxidant Activities

Antibacterial efficacy of novel bismuth-silver nanoparticles synthesis on Staphylococcus aureus and Escherichia coli infection models

Introduction

The emergence of multi-drug-resistant bacteria is one of the main concerns in the health sector worldwide. The conventional strategies for treatment and prophylaxis against microbial infections include the use of antibiotics. However, these drugs are failing due to the increasing antimicrobial resistance. The unavailability of effective antibiotics highlights the need to discover effective alternatives to combat bacterial infections. One option is the use of metallic nanoparticles, which are toxic to some microorganisms due to their nanometric size.

Methods

In this study we (1) synthesize and characterize bismuth and silver nanoparticles, (2) evaluate the antibacterial activity of NPs against Staphylococcus aureus and Escherichia coli in several infection models (in vivo models: infected wound and sepsis and in vitro model: mastitis), and we (3) determine the cytotoxic effect on several cell lines representative of the skin tissue.

Results and discussion

We obtained bimetallic nanoparticles of bismuth and silver in a stable aqueous solution from a single reaction by chemical synthesis. These nanoparticles show antibacterial activity on S. aureus and E. coli in vitro without cytotoxic effects on fibroblast, endothelial vascular, and mammary epithelium cell lines. In an infected-wound mice model, antibacterial effect was observed, without effect on in vitro mastitis and sepsis models.

Fungus-mediated synthesis of Se-BiO-CuO multimetallic nanoparticles as a potential alternative antimicrobial against ESBL-producing Escherichia coli of veterinary origin

Bacterial infections emerge as a significant contributor to mortality and morbidity worldwide. Emerging extended-spectrum β-lactamase (ESBL) Escherichia coli strains provide a greater risk of bacteremia and mortality, are increasingly resistant to antibiotics, and are a major producer of ESBLs. E. coli bacteremia-linked mastitis is one of the most common bacterial diseases in animals, which can affect the quality of the milk and damage organ functions. There is an elevated menace of treatment failure and recurrence of E. coli bacteremia necessitating the adoption of rigorous alternative treatment approaches. In this study, Se-Boil-CuO multimetallic nanoparticles (MMNPs) were synthesized as an alternate treatment from Talaromyces haitouensis extract, and their efficiency in treating ESBL E. coli was confirmed using standard antimicrobial assays. Scanning electron microscopy, UV-visible spectroscopy, and dynamic light scattering were used to validate and characterize the mycosynthesized Se-BiO-CuO MMNPs. UV-visible spectra of Se-BiO-CuO MMNPs showed absorption peak bands at 570, 376, and 290 nm, respectively. The average diameters of the amorphous-shaped Se-BiO-CuO MMNPs synthesized by T. haitouensis extract were approximately 66-80 nm, respectively. Se-BiO-CuO MMNPs (100 μg/mL) showed a maximal inhibition zone of 18.33 ± 0.57 mm against E. coli. Se-BiO-CuO MMNPs also exhibited a deleterious impact on E. coli killing kinetics, biofilm formation, swimming motility, efflux of cellular components, and membrane integrity. The hemolysis assay also confirms the biocompatibility of Se-BiO-CuO MMNPs at the minimum inhibitory concentration (MIC) range. Our findings suggest that Se-BiO-CuO MMNPs may serve as a potential substitute for ESBL E. coli bacteremia.

Leaf Extracts of Moringa oleifera Cultivated in Baghdad: Characterization and Antimicrobial Potential against Endodontic Pathogens

The use of medicinal plant preparations to clean and disinfect root canal infection is gaining popularity. The aim of this study was to evaluate the bioactive composition of leaf extracts of Moringa oleifera plants cultivated in Iraq (specifically Baghdad) and their antimicrobial activity against selected root canal pathogens for potential application in endodontic treatment. Materials and Methods. Moringa leaf extracts were prepared either through cold maceration or warm digestion techniques to perform an ethanolic or aqueous extraction, respectively. Phytochemical detection was performed before thin layer chromatography (TLC) and high-performance liquid chromatography (HPLC) to measure flavonoids and phenolic compounds within both extracts. Then, their antimicrobial activities were investigated against Streptococcus mutans, Enterococcus faecalis, and Candida albicans through minimal inhibitory concentration (MIC), minimal bactericidal concentration (MBC), and agar well diffusion assay in comparison to NaOCl and Ca(OH)2. Results. Phytochemical screening showed several active ingredients but with higher expression of flavonoids and phenolic compounds. Also, different types of these compounds were detected through TLC and quantified by HPLC. MIC values for ethanolic extract against Streptococcus mutans, Enterococcus faecalis, and Candida albicans were 60, 65, and 55, respectively, while for aqueous extract, MIC values were 70, 80, and 50, respectively. Aqueous extract showed a higher inhibition zone than ethanolic extract for both Streptococcus mutans and Enterococcus faecalis with a statistically significant difference (p ≤ 0.001) for all tested materials except with NaOCl and Ca(OH)2 in Streptococcus mutans and Enterococcus faecalis, respectively. The ethanolic extract showed a higher inhibition zone against Candida albicans, with a statistically significant difference (p ≤ 0.001) for all tested materials. Conclusion. Ethanolic and aqueous extracts of Moringa oleifera leaves cultivated in Baghdad contain considerable quantities of phytochemicals, especially flavonoid and phenolic compounds, and demonstrated antimicrobial activities against selected endodontic pathogens. Therefore, Moringa leaf extracts could be suggested as an alternative antimicrobial material in endodontic treatment.

A comprehensive review on Moringa oleifera nanoparticles: importance of polyphenols in nanoparticle synthesis, nanoparticle efficacy and their applications

Moringa oleifera is one of the popular functional foods that has been tremendously exploited for synthesis of a vast majority of metal nanoparticles (NPs). The diverse secondary metabolites present in this plant turn it into a green tool for synthesis of different NPs with various biological activities. In this review, we discussed different types of NPs including silver, gold, titanium oxide, iron oxide, and zinc oxide NPs produced from the extract of different parts of M. oleifera. Different parts of M. oleifera take a role as the reducing, stabilizing, capping agent, and depending on the source of extract, the color of solution changes within NP synthesis. We highlighted the role of polyphenols in the synthesis of NPs among major constituents of M. oleifera extract. The different synthesis methods that could lead to the formation of various sizes and shapes of NPs and play crucial role in biomedical application were critically discussed. We further debated the mechanism of interaction of NPs with various sizes and shapes with the cells, and further their clearance from the body. The application of NPs made from M. oleifera extract as anticancer, antimicrobial, wound healing, and water treatment agent were also discussed. Small NPs show better antimicrobial activity, while they can be easily cleared from the body through the kidney. In contrast, large NPs are taken by the mono nuclear phagocyte system (MPS) cells. In case of shape, the NPs with spherical shape penetrate into the bacteria, and show stronger antibacterial activity compared to the NPs with other shapes. Finally, this review aims to correlate the key characteristics of NPs made from M. oleifera extract, such as size and shape, to their interactions with the cells for designing and engineering them for bio-applications and especially for therapeutic purposes.

Vigna unguiculata L. Walp. Leaves as a Source of Phytochemicals of Dietary Interest: Optimization of Ultrasound-Assisted Extraction and Assessment of Traditional Consumer Habits

Vigna unguiculata L. Walp. is an African crop spread worldwide mainly for pulses production. Despite being a neglected and under-utilized food, cowpea leaves are a rich source of phytochemicals and micronutrients. The aim of the work is to characterize the phytochemical composition of cowpea leaves by an optimized ultrasound-assisted extraction (USAE) and to compare raw and boiled leaves. A three-level factorial design (Box-Behnken) was employed for the optimization of the USAE considering three different parameters (% ethanol, drug-to-solvent ratio, and number of cycles). The optimized extracts were characterized by LC/MS/MS. Finally, leaves were boiled at 100 °C for 30 min to simulate traditional cooking procedures and compared to raw leaves. The best extraction condition was EtOH/H2 O 1 : 2 v/v, drug to solvent ratio 1 : 47 w/v, and 3 extraction cycles. The phytochemicals identified mainly belong to the family of phenolic acids, flavonoids, terpenoids, and alkaloids. Boiled leaves revealed a significant loss of most phytochemicals and a net decrease of their antioxidant activity compared to the raw ones. The results highlight the potential nutraceutical value of cowpea leaves whilst the impoverishment triggered by traditional consumer habits pushes the need to evaluate alternative cooking procedures helpful in the maintenance of their phytochemical properties.

Biological Activities of Bismuth Compounds: An Overview of the New Findings and the Old Challenges Not Yet Overcome

Bismuth-based drugs have been used primarily to treat ulcers caused by Helicobacter pylori and other gastrointestinal ailments. Combined with antibiotics, these drugs also possess synergistic activity, making them ideal for multiple therapy regimens and overcoming bacterial resistance. Compounds based on bismuth have a low cost, are safe for human use, and some of them are also effective against tumoral cells, leishmaniasis, fungi, and viruses. However, these compounds have limited bioavailability in physiological environments. As a result, there is a growing interest in developing new bismuth compounds and approaches to overcome this challenge. Considering the beneficial properties of bismuth and the importance of discovering new drugs, this review focused on the last decade's updates involving bismuth compounds, especially those with potent activity and low toxicity, desirable characteristics for developing new drugs. In addition, bismuth-based compounds with dual activity were also highlighted, as well as their modes of action and structure-activity relationship, among other relevant discoveries. In this way, we hope this review provides a fertile ground for rationalizing new bismuth-based drugs.

Bio-fabricated bismuth-based materials for removal of emerging environmental contaminants from wastewater

Although rapid industrialization has made life easier for humans, several associated issues are emerging and harming the environment. Wastewater is regarded as one of the key problems of the 21st century due to its massive production every year and requires immediate attention from all stakeholders to protect the environment. Since the introduction of nanotechnology, bismuth-based nanomaterials have been used in variety of applications. Various techniques, such as hydrothermal, solvo-thermal and biosynthesis, have been reported for synthesizing these materials, etc. Among these, biosynthesis is eco-friendly, cost-effective, and less toxic than conventional chemical methods. The prime focuses of this review are to elaborate biosynthesis of bismuth-based nanomaterials via bio-synthetic agents such as plant, bacteria and fungi and their application in wastewater treatment as anti-pathogen/photocatalyst for pollutant degradation. Besides this, future perspectives have been presented for the upcoming research in this field, along with concluding remarks.

The role of bismuth nanoparticles in the inhibition of bacterial infection

Bismuth (Bi) combinations have been utilized for the treatment of bacterial infections. In addition, these metal compounds are most frequently utilized for treating gastrointestinal diseases. Usually, Bi is found as bismuthinite (Bi sulfide), bismite (Bi oxide), and bismuthite (Bi carbonate). Newly, Bi nanoparticles (BiNP) were produced for CT imaging or photothermal treatment and nanocarriers for medicine transfer. Further benefits, such as increased biocompatibility and specific surface area, are also seen in regular-size BiNPs. Low toxicity and ecologically favorable attributes have generated interest in BiNPs for biomedical approaches. Moreover, BiNPs offer an option for treating multidrug-resistant (MDR) bacteria because they communicate directly with the bacterial cell wall, induce adaptive and inherent immune reactions, generate reactive oxygen compounds, limit biofilm production, and stimulate intracellular impacts. In addition, BiNPs in amalgamation with X-ray therapy as well as have the capability to treat MDR bacteria. BiNPs as photothermal agents can realize the actual antibacterial through continuous efforts of investigators in the near future. In this article, we summarized the properties of BiNPs, and different preparation methods, also reviewed the latest advances in the BiNPs' performance and their therapeutic effects on various bacterial infections, such as Helicobacter pylori, Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli.

Green synthesis and antimicrobial mechanism of nanoparticles: applications in agricultural and agrifood safety

The growing demand for food and its safety are a challenge for agriculture and agrifood. This has led to the incorporation of alternatives such as organic agriculture, the use of biocontrollers, the development of transgenic plants resistant to pathogens and the incorporation of nanotechnology. In this sense, agrochemicals based on nanoparticles (NPs) have been developed. Recently, the green synthesis of NPs has grown rapidly and, for this reason, molecules, microorganisms, fungi and plants are used. Synthesis from plant extracts offers a broad spectrum and, despite the fact that NPs are usually dispersed in size and shape, extensive antimicrobial effectiveness has been demonstrated at nanomolar concentrations. It has been shown that the mechanism of action can be through the dissipation of the driving force of the protons, the alteration of cellular permeability, the formation of bonds with the thiol group of the proteins, the generation of reactive species of oxygen, and the hyperoxidation of DNA, RNA and even the cell membrane. To improve the efficiency of NPs, modifications have been made such as coating with other metals, the addition of antibiotics, detergents and surfactants, as well as the acidification of the solution. Consequently, NPs are considered as a promising method for achieving safety in the agricultural and agrifood area. However, it is necessary to investigate the side effects of NPs, when applied in agroecological systems, on the textural, nutriment and sensory properties of food, as well as the impact on human health. © 2022 Society of Chemical Industry.

Exploring the potential of eco-friendly silver nanoparticles to inhibit azole-resistant clinical isolates of Candida spp

The antimicrobial activity and biological efficiency of silver nanoparticles (AgNps) have been widely described and can be modeled through stabilizing and reducing agents, especially if they exhibit biocidal properties, which can enhance bioactivity against pathogens. The selective action of AgNps remains a major concern. In this regard, the use of plant extracts for the green synthesis of nanoparticles offers advantages because it improves the toxicity of Nps for microorganisms and is harmless to normal cells. However, biological evaluations of the activity of AgNps synthesized using different reducing agents are determined independently, and comparisons are frequently overlooked. Thus, we investigated and compared the antifungal and cytotoxic effects of two ecological AgNps synthesized from Moringa oleifera aqueous leaf extract (AgNp-M) and glucose (AgNp-G) against azole-resistant clinical isolates of Candida spp. and nontumor mammalian cells. Synthesized AgNps exhibited an antifungal effect on planktonic cells of drug-resistant C. albicans and C. tropicalis (MIC 0.21-52.6 µg/mL). The toxicity was influenced by size. However, the use of M. oleifera extracts allows us to obtain AgNps that are highly selective and nongenotoxic to Vero cells due to modifications of the shape and surface. Therefore, these results suggest that AgNp-M has antimicrobial potential and deserves further investigation for biomedical applications.

In Vitro Biocompatibility of Hydrogel Polyvinyl Alcohol/Moringa oleifera Leaf Extract/Graphene Oxide for Wound Dressing

Hydrogel-based wound dressings are often chosen for healing diabetic foot ulcers (DFU) in combination with herbal extracts. Moringa oleifera leaf (MOL) extract is a potent herb containing antimicrobial and anti-inflammatory bioactive substances. In this work, wound dressings based on polyvinyl alcohol (PVA), MOL extract, and graphene oxide (GO) were developed for DFU wound dressing. The PVA/MOL/GO hydrogel was synthesized using four cycles of a freeze-thaw process with varying concentrations of MOL extract. All hydrogels showed a water content of 83-88% and an equilibrium swelling ratio between 155-171%. After degradation in phosphate-buffered saline, the hydrogels showed a more open porous structure. We observed a degradation rate of 26-28%. Although the increase in MOL extract reduced the tensile strength of the hydrogel, the addition of GO increased the tensile strength. The PVA/MOL/GO hydrogel showed the highest antibacterial activity, with a reduction of 94% Gram-positive S. aureus and 82% Gram-negative E. coli. Finally, all samples possessed appropriate cytocompatibility with cell viability reaching 83-135% in 3T3L1 mouse fibroblast cells. This result was verified by in vitro wound-healing analysis performed by scratch assay. This study presents the potency of combined PVA, MOL, and GO as a biocompatible DFU wound dressing.

Neuroprotective potential of Moringa oleifera mediated by NF-kB/Nrf2/HO-1 signaling pathway: A review

Moringa oleifera is a traditional Indian herb belonging to the Moringaceae family, it is commonly known as the horse-radish tree, drumstick, or sahajna. In developing countries, Moringa is used as feed for both humans and animals due to its well-known antioxidant, anti-inflammatory, and anti-apoptotic properties owing to its several phytoconstituents including β-carotene, quercetin, kaempferol, ascorbic acid, flavonoids, phenolic acid, rhamnose, glycosylates, glucomoringin, and isothiocyanates. These constituents help to maintain the brain antioxidant enzyme levels, mitochondrial functions, and neurogenesis, showing neuroprotective effects in several neurodegenerative disorders including Parkinson's Disease, Alzheimer's Disease, Huntington's Disease, and Amyotrophic lateral sclerosis. This review discusses various phytoconstituent of moringa and their therapeutic potential in various neurological disorders. Additionally, we also concise the safety and toxicity profile, of different molecular pathways involved in the neuroprotective effect of M. oleifera including M. oleifera nanoparticles for better therapeutic value. PRACTICAL APPLICATIONS: Several clinical and preclinical studies on Moringa oleifera have been conducted, and the outcomes indicate moringa could be used in the treatment of brain disorders. As a result, we conclude that moringa and its nanoformulations could be employed to treat neurological problems. In the future, M. oleifera phytoconstituents could be evaluated against specific signaling pathways, which could aid researchers in discovering their mechanism of action. Furthermore, the use of moringa as a nutraceutical owing to its myriad pharmacological potential will go a long way in boosting the economy of countries that grow moringa on a large scale.

Plant as an Alternative Source of Antifungals against Aspergillus Infections: A Review

Aspergillus species consists of a group of opportunistic fungi that is virulent when the immunity of the host is compromised. Among the various species, Aspergillus fumigatus is the most prevalent species. However, the prevalence of fungal infections caused by non-fumigatus Aspergillus has been increasing. Polyenes, echinocandins and azoles are the three main classes of antifungal agents being used for the treatment of aspergillosis. Nevertheless, the incidence of resistance towards these three classes has been rising over the years among several Aspergillus spp. The side effects associated with these conventional antifungal agents have also limited their usage. This urges the need for the discovery of a safe and effective antifungal agent, which presents a major challenge in medicine today. Plants present a rich source of bioactive molecules which have been proven effective against a wide range of infections and conditions. Therefore, this present review intends to examine the current literature available regarding the efficacy and mechanism of action of plant extracts and their compounds against Aspergillus spp. In addition, novel drug delivery systems of plant extracts against Aspergillus spp. were also included in this review.

A review on bismuth-based nanocomposites for energy and environmental applications

Bismuth, a heavy metal which is found to be inexpensive and at a reduced cost, is utilized in the synthesis of different nanomaterials with novel structure, remarkable physical and chemical properties, adjustable bandgap, notable efficiency for photothermal conversion. These characteristics have made this element desirable for various applications such as storage and conversion of energy, electronics, sensors, photocatalysis, and other biomedical applications. These review papers are the vital points for the students, this report guides them to the research papers which focus on the impressive development in the area of bismuth and similar nanostructures. The purpose of the present review is to discuss the various synthesis routes of bismuth-based nanomaterials along with green synthesis, different nanostructures of bismuth, their significant properties, diverse applications and directions for the upcoming research. Therefore, with these different tuneable synthesis methods of bismuth-based nanomaterials combined with their novel properties, would elucidate on the future devices based on various nanostructures of bismuth.

Bismuth nanoparticles against microbial infections

The destructive effect of infectious diseases on human life and the emergence of antibiotic-resistant strains highlight the importance of developing new and appropriate treatment strategies, one of which is the use of metals as therapeutic agents. Bismuth nanoparticles are an example of prominent metal-containing drugs. The therapeutic effects of bismuth-based drugs in the treatment of wounds have been proven. Various laboratory studies have confirmed the antimicrobial effects of bismuth nanoparticles, including the clinical treatment of ulcers caused by Helicobacter pylori. Therefore, considering the performance of this nanoparticle and its potent effect on infectious agents and its therapeutic dimensions, the present study fully investigated the properties and performance of this metal-based nanoparticle.

Comprehensive Study on Lemon Juice-Based Green Synthesis and Catalytic Activity of Bismuth Nanoparticles

Bismuth nanoparticles have gained considerable interest in catalysis because of their small size, large surface-to-volume ratio, and low toxicity. In spite of these advantages, the toxic reagents and solvents used in the synthetic process are significant limitations to their development and utilization. In this study, a green approach employing easily accessible lemon juice was applied for the synthesis of bismuth nanoparticles (BiNPs) as a green alternative to conventional chemical ones. This study clarified the formation and growing process of green-synthesized BiNPs using lemon juice as a reducing and capping agent. The reaction time and amounts of lemon juice significantly affect the growth, morphology, and stability of BiNPs, as confirmed from XRD, DLS, SEM, and TEM analyses. The synthesized BiNPs effectively catalyzed the reduction of 4-nitrophenol to 4-aminophenol in the presence of NaBH₄, and the reduction was significantly accelerated by sunlight and the removal of the fibrous coating layer around BiNPs. Moreover, the synthesized BiNPs also show excellent catalytic efficacy toward the reduction of organic dyes, namely, methyl orange, methylene blue, and rhodamine B. All catalytic reductions followed the pseudo-first-order kinetics, and the rate constants are in the order of k _MB > k _RhB > k _MO > k _4-NP. The stated biogenic synthetic route paves the way for the green industrial fabrication of BiNPs and their uses in catalysis for wastewater treatment.

Prospective Application of Nanoparticles Green Synthesized Using Medicinal Plant Extracts as Novel Nanomedicines

The use of medicinal plants in green synthesis of metal nanoparticles is increasing day by day. A simple search for the keywords "green synthesis" and "nanoparticles" yields more than 33,000 articles in Scopus. As of August 10, 2021, more than 4000 articles have been published in 2021 alone. Besides demonstrating the ease and environmental-friendly route of synthesizing nanomaterials, many studies report the superior pharmacological properties of green synthesized nanoparticles compared to those synthesized by other methods. This is probably due to the fact that bioactive molecules are entrapped on the surface of these nanoparticles. On the other hand, recent studies have confirmed the nano-dimension and biocompatibility of metal ash (Bhasma) preparations, which are commonly macerated with biological products and administered for the treatment of various diseases in Indian medicine since ancient times. This perspective article argues for the prospective medical application of green nanoparticles in the light of Bhasma.

Green synthesis of crystalline bismuth nanoparticles using lemon juice

Lemon juice effectively served as a reducing and capping agent for an easy, cost-effective, and green synthesis of crystalline bismuth nanoparticles (BiNPs) in basic aqueous media. Spherical BiNPs with a rhombohedral crystalline structure are capped by phytochemicals and stably dispersible in aqueous media. The BiNPs effectively catalyze the reduction of 4-nitrophenol to 4-aminophenol by NaBH₄.

Lemon juice effectively served as a reducing and capping agent for an easy, cost-effective, and green synthesis of crystalline bismuth nanoparticles (BiNPs) in basic aqueous media.