Cytotoxicity of Plant-Mediated Synthesis of Metallic Nanoparticles: A Systematic Review

Sustainable synthesis of bionanomaterials using non-native plant extracts for maintaining ecological balance: A computational bibliography analysis

Biological approaches via biomolecular extracts of bacteria, fungi, or plants have recently been introduced as an alternative approach to synthesizing less or nontoxic nanomaterials, compared to conventional physical and chemical approaches. Among these biological methods, plant-mediated approaches (phytosynthesis) are reported to be highly beneficial for large-scale, nontoxic nanomaterial synthesis. However, plant-mediated synthesis of nanomaterials using native plant extract can lead to bioprospecting issues and deforestation challenges. On the other hand, non-native or invasive plants are non-indigenous to a particular geographic location that can grow and spread rapidly, ultimately disrupting the local and endogenous plant communities or ecosystems. Thus, controlling or eradicating these non-native plants before they damage the ecosystem is necessary. Even though mechanical, chemical, and biological approaches are available to control non-native plants, all these methods possess certain limitations, such as environmental toxicity, disturbance in the nutrient cycle, and loss of genetic integrity. Therefore, non-native plants were recently proposed as a novel sustainable source of phytochemicals for preparing nanomaterials via green chemistry, mainly metallic nanoparticles, as an alternative to native, agriculture-based, or medicinal plants. This work aims to cover a literature gap on plant-mediated bionanomaterial synthesis with an overview and bibliography analysis of non-native plants via novel data mining and advanced visualization tools. In addition, the potential of non-native plants as a sustainable, green chemistry-based alternative for bionanomaterial preparation for maintaining ecological balance, the mechanism of formation via phytochemicals, and their possible applications to promote their control and spread were also discussed. The bibliography analysis revealed that only an average of 4 articles have been published in the last 10 years (2013-2023) on non-native/invasive plants for nanomaterial synthesis, which shows the significance of this article.

Plant leads for mitigation of oral submucous fibrosis: Current scenario and future prospect

The aim of this review is to enumerate medicinal plants and their bioactive compounds that may become potential leads in the mitigation of oral submucous fibrosis (OSMF) in the forthcoming future. It is focused on pathophysiology, risk factors, current treatment regimen, potential plant leads, and future therapies for OSMF. Data were extracted from a vast literature survey by using SciFinder, Web of Science, Google Scholar, and PubMed search engines with relevant keywords. Upon literature survey, we found that the phytochemical 'arecoline' present in the areca nut is the main causative agent of OSMF condition. Currently, OSMF is treated by immunomodulatory and anti-inflammatory agents such as corticosteroids, enzymes (hyaluronidase, chymotrypsin, and collagenase), anti-inflammatory mediators (isoxsuprine and pentoxifylline), dietary supplements (vitamins, antioxidants, and micronutrients), and anti-fibrotic cytokines like interferon-gamma that provides short-term symptomatic relief to OSMF patients. However, some plant leads have been proven effective in alleviating symptoms and mitigating OSMF, which ultimately improves the quality of OSMF patients' life. We concluded that plant drugs like lycopene, curcumin, Aloe vera, colchicine, and Glycyrrhiza glabra are effective against OSMF in various in vitro and/or clinical studies and are being used by modern and traditional practitioners.

Harvesting the Power of Green Synthesis: Gold Nanoparticles Tailored for Prostate Cancer Therapy

Biosynthetic gold nanoparticles (bAuNPs) present a promising avenue for enhancing bio-compatibility and offering an economically and environmentally responsible alternative to traditional production methods, achieved through a reduction in the use of hazardous chemicals. While the potential of bAuNPs as anticancer agents has been explored, there is a limited body of research focusing on the crucial physicochemical conditions influencing bAuNP production. In this study, we aim to identify the optimal growth phase of Pseudomonas aeruginosa cultures that maximizes the redox potential and coordinates the formation of bAuNPs with increased efficiency. The investigation employs 2,6-dichlorophenolindophenol (DCIP) as a redox indicator. Simultaneously, we explore the impact of temperature, pH, and incubation duration on the biosynthesis of bAuNPs, with a specific emphasis on their potential application as antitumor agents. Characterization of the resulting bAuNPs is conducted using ATR-FT-IR, TEM, and UV-Vis spectroscopy. To gain insights into the anticancer potential of bAuNPs, an experimental model is employed, utilizing both non-neoplastic (HPEpiC) and neoplastic (PC3) epithelial cell lines. Notably, P. aeruginosa cultures at 9 h/OD600 = 1, combined with biosynthesis at pH 9.0 for 24 h at 58 °C, produce bAuNPs that exhibit smaller, more spherical, and less aggregated characteristics. Crucially, these nanoparticles demonstrate negligible effects on HPEpiC cells while significantly impacting PC3 cells, resulting in reduced viability, migration, and lower IL-6 levels. This research lays the groundwork for the development of more specialized, economical, and ecologically friendly treatment modalities.

Radiofrequency driving antitumor effect of graphene oxide-based nanocomposites: a Hill model analysis

Aim: This report proposes using the Hill model to assess the benchmark dose, the 50% lethal dose, the cooperativity and the dissociation constant while analyzing cell viability data using nanomaterials to evaluate the antitumor potential while combined with radiofrequency therapy. Materials & methods: A nanocomposite was synthesized (graphene oxide-polyethyleneimine-gold) and the viability was evaluated using two tumor cell lines, namely LLC-WRC-256 and B16-F10. Results: Our findings demonstrated that while the nanocomposite is biocompatible against the LLC-WRC-256 and B16-F10 cancer cell lines in the absence of radiofrequency, the application of radiofrequency enhances the cell toxicity by orders of magnitude. Conclusion: This result points to prospective studies with the tested cell lines using tumor animal models.

Four Ounces Can Move a Thousand Pounds: The Enormous Value of Nanomaterials in Tumor Immunotherapy

The application of nanomaterials in healthcare has emerged as a promising strategy due to their unique structural diversity, surface properties, and compositional diversity. In particular, nanomaterials have found a significant role in improving drug delivery and inhibiting the growth and metastasis of tumor cells. Moreover, recent studies have highlighted their potential in modulating the tumor microenvironment (TME) and enhancing the activity of immune cells to improve tumor therapy efficacy. Various types of nanomaterials are currently utilized as drug carriers, immunosuppressants, immune activators, immunoassay reagents, and more for tumor immunotherapy. Necessarily, nanomaterials used for tumor immunotherapy can be grouped into two categories: organic and inorganic nanomaterials. Though both have shown the ability to achieve the purpose of tumor immunotherapy, their composition and structural properties result in differences in their mechanisms and modes of action. Organic nanomaterials can be further divided into organic polymers, cell membranes, nanoemulsion-modified, and hydrogel forms. At the same time, inorganic nanomaterials can be broadly classified as nonmetallic and metallic nanomaterials. The current work aims to explore the mechanisms of action of these different types of nanomaterials and their prospects for promoting tumor immunotherapy.

Updates on Biogenic Metallic and Metal Oxide Nanoparticles: Therapy, Drug Delivery and Cytotoxicity

The ambition to combat the issues affecting the environment and human health triggers the development of biosynthesis that incorporates the production of natural compounds by living organisms via eco-friendly nano assembly. Biosynthesized nanoparticles (NPs) have various pharmaceutical applications, such as tumoricidal, anti-inflammatory, antimicrobials, antiviral, etc. When combined, bio-nanotechnology and drug delivery give rise to the development of various pharmaceutics with site-specific biomedical applications. In this review, we have attempted to summarize in brief the types of renewable biological systems used for the biosynthesis of metallic and metal oxide NPs and the vital contribution of biogenic NPs as pharmaceutics and drug carriers simultaneously. The biosystem used for nano assembly further affects the morphology, size, shape, and structure of the produced nanomaterial. The toxicity of the biogenic NPs, because of their pharmacokinetic behavior in vitro and in vivo, is also discussed, together with some recent achievements towards enhanced biocompatibility, bioavailability, and reduced side effects. Because of the large biodiversity, the potential biomedical application of metal NPs produced via natural extracts in biogenic nanomedicine is yet to be explored.

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.

Spectroscopic investigations on the interaction between nano plastic and catalase on molecular level

As an emerging pollutant that is easily bonded with some functional proteins and the effects of their physiological expressions, nano plastics (NPs) have been widely detected in various environmental mediums, even in human blood. Compared to microplastics, less information on the interactions between NPs and proteins has been reported. Here, the interaction mechanism between common polystyrene nano plastics (PSNPs) and catalase (CAT) under two typical physiological conditions, pH 7.4 and 4.0, was investigated by UV-visible spectroscopy, circular dichroism (CD), and dynamic light scattering (DLS). Compared with the enhanced catalytic effects when increasing PSNPs at pH 7.4, a trend of initial inhibition and enhanced activity was observed at pH 4.0. Spectroscopic analysis and calculation results indicated that their binding was static, with only one binding site and stronger interactions under acidic conditions. UV-visible and CD spectra analysis demonstrated that the difference in enzymatic activity could be mainly attributed to the conformational alternation of CAT in the presence of PSNPs, which is obviously affected by solution chemistry. The change was also revealed by the hydrodynamic diameter and zeta potentials of the complexes supplied by DLS analysis. This study will help understand the health risks of nano plastic pollution and provide a theoretical basis for studying their toxicological effects.

Highin vitroactivity of gold and silver nanoparticles from Solanum mammosum L. against SARS-CoV-2 surrogate Phi6 and viral model PhiX174

The search for new strategies to curb the spread of the SARS-CoV-2 coronavirus, which causes COVID-19, has become a global priority. Various nanomaterials have been proposed as ideal candidates to inactivate the virus; however, because of the high level of biosecurity required for their use, alternative models should be determined. This study aimed to compare the effects of two types of nanomaterials gold (AuNPs) and silver nanoparticles (AgNPs), recognized for their antiviral activity and affinity with the coronavirus spike protein using PhiX174 and enveloped Phi6 bacteriophages as models. To reduce the toxicity of nanoparticles, a species known for its intermediate antiviral activity,Solanum mammosumL. (Sm), was used. NPs prepared with sodium borohydride (NaBH₄) functioned as the control. Antiviral activity against PhiX174 and Phi6 was analyzed using its seed, fruit, leaves, and essential oil; the leaves were the most effective on Phi6. Using the aqueous extract of the leaves, AuNPs-Sm of 5.34 ± 2.25 nm and AgNPs-Sm of 15.92 ± 8.03 nm, measured by transmission electron microscopy, were obtained. When comparing NPs with precursors, both gold(III) acetate and silver nitrate were more toxic than their respective NPs (99.99% at 1 mg ml^-1). The AuNPs-Sm were less toxic, reaching 99.30% viral inactivation at 1 mg ml^-1, unlike the AgNPs-Sm, which reached 99.94% at 0.01 mg ml^-1. In addition, cell toxicity was tested in human adenocarcinoma alveolar basal epithelial cells (A549) and human foreskin fibroblasts. Gallic acid was the main component identified in the leaf extract using high performance liquid chromatography with diode array detection (HPLC-DAD). The FT-IR spectra showed the presence of a large proportion of polyphenolic compounds, and the antioxidant analysis confirmed the antiradical activity. The control NPs showed less antiviral activity than the AuNPs-Sm and AgNPs-Sm, which was statistically significant; this demonstrates that both theS. mammosumextract and its corresponding NPs have a greater antiviral effect on the surrogate Phi bacteriophage, which is an appropriate model for studying SARS-CoV-2.

Biogeneration of silver nanoparticles from Cuphea procumbens for biomedical and environmental applications

Nanotechnology is one of the most important and relevant disciplines today due to the specific electrical, optical, magnetic, chemical, mechanical and biomedical properties of nanoparticles. In the present study we demonstrate the efficacy of Cuphea procumbens to biogenerate silver nanoparticles (AgNPs) with antibacterial and antitumor activity. These nanoparticles were synthesized using the aqueous extract of C. procumbens as reducing agent and silver nitrate as oxidizing agent. The Transmission Electron Microscopy demonstrated that the biogenic AgNPs were predominantly quasi-spherical with an average particle size of 23.45 nm. The surface plasmonic resonance was analyzed by ultraviolet visible spectroscopy (UV-Vis) observing a maximum absorption band at 441 nm and Infrared Spectroscopy (FT IR) was used in order to structurally identify the functional groups of some compounds involved in the formation of nanoparticles. The AgNPs demonstrated to have antibacterial activity against the pathogenic bacteria Escherichia coli and Staphylococcus aureus, identifying the maximum zone of inhibition at the concentration of 0.225 and 0.158 µg/mL respectively. Moreover, compared to the extract, AgNPs exhibited better antitumor activity and higher therapeutic index (TI) against several tumor cell lines such as human breast carcinoma MCF-7 (IC₅₀ of 2.56 µg/mL, TI of 27.65 µg/mL), MDA-MB-468 (IC₅₀ of 2.25 µg/mL, TI of 31.53 µg/mL), human colon carcinoma HCT-116 (IC₅₀ of 1.38 µg/mL, TI of 51.07 µg/mL) and melanoma A-375 (IC₅₀ of 6.51 µg/mL, TI of 10.89 µg/mL). This fact is of great since it will reduce the side effects derived from the treatment. In addition, AgNPs revealed to have a photocatalytic activity of the dyes congo red (10^-3 M) in 5 min and malachite green (10^-3 M) in 7 min. Additionally, the degradation percentages were obtained, which were 86.61% for congo red and 82.11% for malachite green. Overall, our results demonstrated for the first time that C. procumbens biogenerated nanoparticles are excellent candidates for several biomedical and environmental applications.

In Vivo Evaluation of Anti-Nociceptive Effects of Silver Nanoparticles

Silver nanoparticles (AgNPs) are widely used commercially due to their antimicrobial effects. Little is known about the effect of AgNPs on neural transmission and pain response. The aim of this study was to assess the anti-nociceptive activity of AgNPs. AgNPs were prepared at 16 ug/mL, white albino rats were injected with various doses of AgNPs, and challenged using a hot-plate test and paw withdrawal latency (PWL) was measured. The chronic constriction injury (CCI) model was utilized to evaluate the pedal withdrawal reflex and tail withdrawal reflex. An electrophysiological study was conducted utilizing colon longitudinal muscle strips. AgNPs increased the latency of PWL in a dose-dependent matter over the duration of 6 h. The paw withdrawal threshold in animals with CCI significantly increased after AgNPs administration. In isolated colon longitudinal muscle strips, AgNPs significantly reduced the colonic migrating motor complexes (MMCs) and contraction. This action was completely reversed after removing the AgNPs and adding acetylcholine to the preparation. In this study, AgNPs showed significant anti-nociception properties. To our knowledge, this is the first report to describe this pharmacological action of AgNPs.

Antineoplastic activity of biogenic silver and gold nanoparticles to combat leukemia: Beginning a new era in cancer theragnostic

The American Cancer Society estimated around 61,090 new cases of leukemia were diagnosed, and around 23,660 people died from this disease in the United States alone in 2021. Due to its burden on society, there is an unmet need to explore innovative approaches to overcome leukemia. Among different strategies that have been explored, nanotechnology appears to be a promising and effective approach for therapeutics. Specifically, biogenic silver and gold nanoparticles (NPs) have attracted significant attention for their antineoplastic activity toward leukemia cancer cells due to their unique physicochemical properties. Indeed, these nanostructures have emerged as useful approaches in anti-leukemic applications, either as carriers to enhance drug bioavailability and its targeted delivery to a specific organ or as a novel therapeutic agent. This review explores recent advances in green synthesized nanomaterials and their potential use against leukemia, especially focusing on silver (Ag) and gold (Au) nanostructures. In detail, we have reviewed various eco-friendly methods of bio-synthesized NPs, their analytical properties, and toxicity effects against leukemic models. This overview confirms the satisfactory potency of biogenic NPs toward leukemic cells and desirable safety profiles against human native cells, which opens a promising door toward commercializing these types of nontherapeutic agents if challenges involve clinical validations, reproducibility, and scalability could be resolved.

Methods for Green Synthesis of Metallic Nanoparticles Using Plant Extracts and their Biological Applications - A Review

Nanotechnology, a fast-developing branch of science, is gaining extensive popularity among researchers simply because of the multitude of applications it can offer. In recent years, biological synthesis has been widely used instead of physical and chemical synthesis methods, which often produce toxic products. These synthesis methods are now being commonly adapted to discover new applications of nanoparticles synthesized using plant extracts. In this review, we elucidate the various ways by which nanoparticles can be biologically synthesized. We further discuss the applications of these nanoparticles.

Biogenic Silver Nanoparticles Strategically Combined With Origanum vulgare Derivatives: Antibacterial Mechanism of Action and Effect on Multidrug-Resistant Strains

Multidrug-resistant bacteria have become a public health problem worldwide, reducing treatment options against several pathogens. If we do not act against this problem, it is estimated that by 2050 superbugs will kill more people than the current COVID-19 pandemic. Among solutions to combat antibacterial resistance, there is increasing demand for new antimicrobials. The antibacterial activity of binary combinations containing bioAgNP (biogenically synthesized silver nanoparticles using Fusarium oxysporum), oregano essential oil (OEO), carvacrol (Car), and thymol (Thy) was evaluated: OEO plus bioAgNP, Car plus bioAgNP, Thy plus bioAgNP, and Car plus Thy. This study shows that the mechanism of action of Thy, bioAgNP, and Thy plus bioAgNP involves damaging the membrane and cell wall (surface blebbing and disruption seen with an electron microscope), causing cytoplasmic molecule leakage (ATP, DNA, RNA, and total proteins) and oxidative stress by enhancing intracellular reactive oxygen species and lipid peroxidation; a similar mechanism happens for OEO and Car, except for oxidative stress. The combination containing bioAgNP and oregano derivatives, especially thymol, shows strategic antibacterial mechanism; thymol disturbs the selective permeability of the cell membrane and consequently facilitates access of the nanoparticles to bacterial cytoplasm. BioAgNP-treated Escherichia coli developed resistance to nanosilver after 12 days of daily exposition. The combination of Thy and bioAgNP prevented the emergence of resistance to both antimicrobials; therefore, mixture of antimicrobials is a strategy to extend their life. For antimicrobials alone, minimal bactericidal concentration ranges were 0.3-2.38 mg/ml (OEO), 0.31-1.22 mg/ml (Car), 0.25-1 mg/ml (Thy), and 15.75-31.5 μg/ml (bioAgNP). The time-kill assays showed that the oregano derivatives acted very fast (at least 10 s), while the bioAgNP took at least 30 min to kill Gram-negative bacteria and 7 h to kill methicillin-resistant Staphylococcus aureus (MRSA). All the combinations resulted in additive antibacterial effect, reducing significantly minimal inhibitory concentration and acting faster than the bioAgNP alone; they also showed no cytotoxicity. This study describes for the first time the effect of Car and Thy combined with bioAgNP (produced with F. oxysporum components) against bacteria for which efficient antimicrobials are urgently needed, such as carbapenem-resistant strains (E. coli, Klebsiella pneumoniae, Acinetobacter baumannii, and Pseudomonas aeruginosa) and MRSA.

The Potential Application of Green-Synthesized Metal Nanoparticles in Dentistry: A Comprehensive Review

Orodental problems have long been managed using herbal medicine. The development of nanoparticle formulations with herbal medicine has now become a breakthrough in dentistry because the synthesis of biogenic metal nanoparticles (MNPs) using plant extracts can address the drawbacks of herbal treatments. Green production of MNPs such as Ag, Au, and Fe nanoparticles enhanced by plant extracts has been proven to be beneficial in managing numerous orodental disorders, even outperforming traditional materials. Nanostructures are utilized in dental advances and diagnostics. Oral disease prevention medicines, prostheses, and tooth implantation all employ nanoparticles. Nanomaterials can also deliver oral fluid or pharmaceuticals, treating oral cancers and providing a high level of oral healthcare. These are also found in toothpaste, mouthwash, and other dental care products. However, there is a lack of understanding about the safety of nanomaterials, necessitating additional study. Many problems, including medication resistance, might be addressed using nanoparticles produced by green synthesis. This study reviews the green synthesis of MNPs applied in dentistry in recent studies (2010–2021).

Synthesis, characterization and anticancer activities of silver nanoparticles from the leaves of Datura stramonium L

In recent years, a wide range of studies has pointed out the role of nanoparticles as reservoirs of therapeutics for several diseases, including cancer. Nowadays, cancer research is focused on the development of novel treatment approaches to fight this dreadful disorder. Based on the evidential research and applications of nanoparticles, it is expected that green synthesized nanoparticles may show a prominent role, especially in the biomedical field. The present work is centered on the preparation and characterization of silver nanoparticles (Ag-NPs) from the aqueous (AQ) extract and non-alkaloidal (NA) fraction of Datura stramonium leaves and to evaluate their anticancer potential against mammalian cell lines. The biogenic Ag-NPs are characterized by UV-vis spectra, FTIR DLS, UV-Vis, SEM, and TEM. SEM and TEM analysis reveals the spherical morphology of NPs. The Ag-NPs exhibit cytotoxicity against various mammalian cell lines (A549, HCT-116, PANC-1, SHSY5Y, and U87), which indicate that the AQ and NA based NPs are highly potent to cause cancer cell death. To the best of our knowledge, the present report, for the first time, describes the green synthesis of Ag-NPs from the NA fraction of the D. stramonium and provides pieces of evidence for its anticancer potential.

Gold Nanoparticles: Biosynthesis and Potential of Biomedical Application

Gold nanoparticles (AuNPs) are extremely promising objects for solving a wide range of biomedical problems. The gold nanoparticles production by biological method ("green synthesis") is eco-friendly and allows minimization of the amount of harmful chemical and toxic byproducts. This review is devoted to the AuNPs biosynthesis peculiarities using various living organisms (bacteria, fungi, algae, and plants). The participation of various biomolecules in the AuNPs synthesis and the influence of size, shapes, and capping agents on the functionalities are described. The proposed action mechanisms on target cells are highlighted. The biological activities of "green" AuNPs (antimicrobial, anticancer, antiviral, etc.) and the possibilities of their further biomedical application are also discussed.

A Review on Drug Delivery System for Tumor Therapy

In recent years, with the development of nanomaterials, the research of drug delivery systems has become a new field of cancer therapy. Compared with conventional antitumor drugs, drug delivery systems such as drug nanoparticles (NPs) are expected to have more advantages in antineoplastic effects, including easy preparation, high efficiency, low toxicity, especially active tumor-targeting ability. Drug delivery systems are usually composed of delivery carriers, antitumor drugs, and even target molecules. At present, there are few comprehensive reports on a summary of drug delivery systems applied for tumor therapy. This review introduces the preparation, characteristics, and applications of several common delivery carriers and expounds the antitumor mechanism of different antitumor drugs in delivery carriers in detail which provides a more theoretical basis for clinical application of personalized cancer nanomedicine in the future.

Mechanistic aspects of plant-based silver nanoparticles against multi-drug resistant bacteria

Resistance among pathogenic bacteria to the existing antibiotics is one of the most alarming problems of the modern world. Alongwith reducing the use of antibiotics, and antibiotic stewardship, an alternative to antibiotics is much needed in the current scenario to combact infectious diseases. One alternative is to produce nanomaterials, especially, silver nanoparticles (AgNPs) against antibiotic-resistant bacteria. AgNPs are the most vital and fascinating nanoparticles because of their unique structural and functional properties and application against pathogenic bacteria. However, the synthesis of AgNPs remains a problem because of the chemicals and energy requirements and the byproducts of the reactions. Concerns have been raised about using chemically and physically synthesized nanoparticles because of their potential risks to the human body, animals, and environment. Green synthesis of these nanoparticles is a better alternative to physical and chemical approaches. Plant-based synthesis in turn is a method which can provide AgNPs that are cost-effective and eco-friendly as well as biocompatible. The specific features of size, morphology and shape of plant-based AgNPs give them the potency to fight multi-drug resistant bacteria. A detailed look into mechanistic aspects of the action of AgNPs against resistant bacteria with a focus on characteristic properties of AgNPs is required. This review discusses in detail these aspects and the potential of plant-based AgNPs as a solution to antibiotic resistance.

Biogenic Silver Nanoparticles of Clinacanthus nutans as Antioxidant with Antimicrobial and Cytotoxic Effects

Silver nanoparticles (AgNPs) previously synthesised using leaf (AgNP-L) and stem (AgNP-S) extracts of Clinacanthus nutans (C. nutans) were tested to evaluate antimicrobial, antioxidant, and cytotoxicity activities. The AgNPs showed good inhibition against bacteria, but not fungi. The inhibition results showed the highest activity against Staphylococcus aureus (S. aureus) with 11.35 mm (AgNP-L) and 11.52 mm (AgNP-S), while the lowest inhibition was against Escherichia coli (E. coli) with 9.22 mm (AgNP-L) and 9.25 mm (AgNP-S) in the disc diffusion method. The same trend of results was noted in the well diffusion method. The IC50 of AgNP-L and AgNP-S in 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assays was 417.05 μg/mL and 434.60 μg/mL, as well as 304.31 μg/mL and 326.83 μg/mL, respectively. Ferric reducing power (FRAP) assay showed that AgNP-L [872.389 μmol/L Fe(II)] and AgNP-S [612.770 μmol/L Fe(II)] exhibited significantly (p < 0.05) greater antioxidant activities than leaf extract (CNL) [152.260 μmol/L Fe(II)] and stem extract (CNS) [110.445 μmol/L Fe(II)] of C. nutans. The AgNPs were also proven to possess cytotoxic effects on the breast (MCF-7), cervical (HeLa), and colon (HT-29) cancer cells in a dose-dependent manner. AgNP-S and AgNP-L showed significantly (p < 0.05) higher cytotoxicity against MCF-7 (117.43 μg/mL) and HT-29 (78.47 μg/mL), respectively. In conclusion, the biosynthesised AgNPs from aqueous extract leaves and stem of C. nutans have demonstrated promising potential towards antioxidant, antimicrobial, and cytotoxicity activities.

Wheat Germ Agglutinin-Conjugated Disulfide Cross-Linked Alginate Nanoparticles as a Docetaxel Carrier for Colon Cancer Therapy

PURPOSE

In chemotherapy, oral administration of drug is limited due to lack of drug specificity for localized colon cancer cells. The inability of drugs to differentiate cancer cells from normal cells induces side effects. Colonic targeting with polymeric nanoparticulate drug delivery offers high potential strategies for delivering hydrophobic drugs and fewer side effects to the target site. Disulfide cross-linked polymers have recently acquired high significance due to their potential to degrade in reducing colon conditions while resisting the upper gastrointestinal tract's hostile environment. The goal of this project is, therefore, to develop pH-sensitive and redox-responsive fluorescein-labeled wheat germ agglutinin (fWGA)-mounted disulfide cross-linked alginate nanoparticles (fDTP2) directly targeting docetaxel (DTX) in colon cancer cells.

METHODS

fDTP2 was prepared by mounting fWGA on DTX-loaded nanoparticles (DTP2) using the two-step carbodiimide method. Morphology of fDTP2 was examined using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Dynamic light scattering (DLS) study was carried out to determine the mean diameter, polydispersity index (PDI) and zeta potential of fDTP2. Cellular uptake efficiency was examined using fluorescence microplate reader. Biocompatibility and active internalization of fDTP2 were conducted on HT-29.

RESULTS

fDTP2 was found to exhibit a DTX loading efficiency of 19.3%. SEM and TEM tests revealed spherical nanoparticles. The in vitro DTX release test showed a cumulative release of 54.7%. From the DLS study, fDTP2 reported a 277.7 nm mean diameter with PDI below 0.35 and -1.0 mV zeta potential. HT-29 which was fDTP2-treated demonstrated lower viability than L929 with a half maximal inhibitory concentration (IC50) of 34.7 µg/mL. HT-29 (33.4%) internalized fDTP2 efficiently at 2 h incubation. The study on HT-29 active internalization of nanoparticles through fluorescence and confocal imaging indicated such.

CONCLUSION

In short, fDTP2 demonstrated promise as a colonic drug delivery DTX transporter.

Cytotoxicity of targeted PLGA nanoparticles: a systematic review

Recent advances in nanotechnology have contributed tremendously to the development and revolutionizing of drug delivery systems in the field of nanomedicine. In particular, targeting nanoparticles based on biodegradable poly(lactic-co-glycolic acid) (PLGA) polymers have gained much interest. However, PLGA nanoparticles remain of concern for their effectiveness against cancer cells and their toxicity to normal cells. The aim of this systematic review is to identify a promising targeting PLGA nanoformulation based on the comparison study of their cytotoxicity potency in different cell lines. A literature search was conducted through the databases of Google Scholar, PubMed, ScienceDirect, Scopus and SpringerLink. The sources studied were published between 2009 and 2019, and a variety of keywords were utilized. In total, 81 manuscripts that met the inclusion and exclusion criteria were selected for analysis based on their cytotoxicity, size, zeta potential, year of publication, type of ligand, active compounds and cell line used. The half maximal inhibitory concentration (IC50) for cytotoxicity was the main measurement in this data extraction, and the SI units were standardized to μg mL-1 for a better view of comparison. This systematic review also identified that cytotoxicity potency was inversely proportional to nanoparticle size. The PLGA nanoparticles predominantly exhibited a size of less than 300 nm and absolute zeta potential ∼20 mV. In conclusion, more comprehensive and critical appraisals of pharmacokinetic, pharmacokinetic, toxicokinetic, in vivo and in vitro tests are required for the investigation of the full value of targeting PLGA nanoparticles for cancer treatment.

Biocompatibility assessment of silver chloride nanoparticles derived from Padina gymnospora and its therapeutic potential

The objective of the present work was to improve the biological activity of Padina gymnospora. In the current study, silver chloride nanoparticles have been synthesized using the aqueous extract of Padina gymnospora and further characterized by ultraviolet-visible spectroscopy, Fourier-transform infrared spectroscopy, x-ray powder diffraction, scanning electron microscopy, energy dispersive spectroscopy, transmission electron microscopy and atomic force microscope. Further, the hemolytic activity and eco-toxicity of silver chloride nanoparticles analyzed. The synthesized silver chloride nanoparticles were found to be mono-dispersed and spherical with an average size of 11.5–32.86 nm. The particles showed an anticancer effect in a dose-dependent manner against breast cancer cell line (MCF-7 cell lines) (IC50 = 31.37 μg ml−1). In addition, it showed the larvicidal activity against Aedes aegypti at a lower dose (3.92 μg ml−1) than that of the aqueous extract (13.01 μg ml−1). Nanoparticles also exhibited greater antimicrobial activity for both bacterial and fungal pathogens. The synthesized silver chloride nanoparticles showed a maximum zone of inhibition, i.e., 31 mm for Candida albicans followed and 27 mm for vancomycin resistance Enterococcus faecalis.The results suggest the possible use of synthesized silver nanoparticles with P. gymnospora as therapeutic agent for breast cancer, dengue vector control and as antimicrobial agent.

Oral Nano Drug Delivery Systems for the Treatment of Type 2 Diabetes Mellitus: An Available Administration Strategy for Antidiabetic Phytocompounds

In view of the worldwide serious health threat of type 2 diabetes mellitus (T2DM), natural sources of chemotherapies have been corroborated as the promising alternatives, with the excellent antidiabetic activities, bio-safety, and more cost-effective properties. However, their clinical application is somewhat limited, because of the poor solubility, instability in the gastrointestinal tract (GIT), low bioavailability, and so on. Nowadays, to develop nanoscaled systems has become a prominent strategy to improve the drug delivery of phytochemicals. In this review, we primarily summarized the intervention mechanisms of phytocompounds against T2DM and presented the recent advances in various nanosystems of antidiabetic phytocompounds. Selected nanosystems were grouped depending on their classification and structures, including polymeric NPs, lipid-based nanosystems, vesicular systems, inorganic nanocarriers, and so on. Based on this review, the state-of-the-art nanosystems for phytocompounds in T2DM treatment have been presented, suggesting the preponderance and potential of nanotechnologies.

Catalytic Degradability of p-Nitrophenol Using Ecofriendly Silver Nanoparticles

In an effort to produce non-toxic and economically viable “green” protocols for waste water treatment, researchers are actively involved to develop versatile and effective silver nanoparticles (SNPs) as nano-catalyst from bio-based techniques. Since, p-nitrophenol (PNP) is one of the anthropogenic contaminants, considerable attention has been focused in catalytic degradability of PNP in wastewater treatment by curtailing serious effect on aquatic fauna. Ingestion of contaminants by aquatic organisms will not only affect the aquatic species but is also a potential threat to human health, especially if the toxic contaminants are involved in food chain. In this short report, we provided a comprehensive insight on few remarkable nanocatalysts especially based on SNPs and its biopolymer composites synthesized via ecofriendly “green” route. The beneficiality and catalytic performance of these silver nanocatalysts are concisely documented on standard model degradation reduction of PNP to p-aminophenol (PAP) in the presence of aqueous sodium borohydride. The catalytic degradation of PNP to PAP using SNPs follows pseudo first order kinetics involving six-electrons with lower activation energy. Furthermore, we provided a list of highly effective, recoverable, and economically viable SNPs, which demonstrated its potential as nanocatalysts by focusing its technical impact in the area of water remediation.

Anticancer potential of AgNPs synthesized using Acinetobacter sp. and Curcuma aromatica against HeLa cell lines: A comparative study

BACKGROUND

Biogenic nanoparticles are gaining attention due to their low toxicity and numerous biomedical applications. Present study aimed to compare the potential anticancer activity of two biogenic silver nanoparticles (bAgNPs and pAgNPs) against human cervical cancer cell lines (HeLa).

METHODS

bAgNPs were synthesized using Acinetobacter sp. whereas pAgNPs were synthesized using aqueous root extract of Curcuma aromatica. Effect of these nanoparticles on HeLa cells viability was studied using MTT assay and colony formation assay. Anticancer potential was determined using fluorescence microscopy and flow cytometry studies. Bio-compatibility studies were performed against peripheral blood mononuclear cells (PBMCs).

RESULTS

Both the nanoparticles showed 50 % viability of peripheral blood mononuclear cells (PBMCs) when used at high concentration (200 μg/mL). IC₅₀ for bAgNPs and pAgNPs against HeLa cells were 17.4 and 14 μg/mL respectively. Colony formation ability of Hela cells was reduced on treatment with both nanoparticles. Acridine orange and ethidium bromide staining demonstrated that bAgNPs were cytostatic whereas pAgNPs were apoptotic. JC-1 dye staining revealed that the mitochondrial membrane potential was affected on treatment with pAgNPs while it remained unchanged on bAgNPs treatment. Flow cytometry confirmed cell cycle arrest in HeLa cells on treatment with nanoparticles further leading to apoptosis in case of pAgNPs. About 77 and 58 % HeLa cells were found in subG1 phase on treatment with bAgNPs and pAgNPs respectively. bAgNPs showed cytostatic effect on HeLa cells arresting the cell growth in subG1 phase, whereas, pAgNPs triggered death of HeLa cells through mitochondrial membrane potential impairment and apoptosis.

CONCLUSION

Overall, bAgNPs and pAgNPs could be safe and showed potential to be used as anticancer nano-antibiotics against human cervical cancer cells.

Cytotoxicity and insulin resistance reversal ability of biofunctional phytosynthesized MgO nanoparticles

The present study investigates the cytotoxicity of hexagonal MgO nanoparticles synthesized via Amaranthus tricolor leaf extract and spherical MgO nanoparticles synthesized via Amaranthus blitum and Andrographis paniculata leaf extracts. In vitro cytotoxicity analysis showed that the hexagonal MgO nanoparticles synthesized from A. tricolor extract demonstrated the least toxicity to both diabetic and non-diabetic cells at 600 μl/ml dosage. The viability of the diabetic cells (3T3-L1) after incubation with varying dosages of MgO nanoparticles was observed to be 55.3%. The viability of normal VERO cells was 86.6% and this stabilized to about 75% even after exposure to MgO nanoparticles dosage of up to 1000 μl/ml. Colorimetric glucose assay revealed that the A. tricolor extract synthesized MgO nanoparticles resulted in ~ 28% insulin resistance reversal. A reduction in the expression of GLUT4 protein at 54 KDa after MgO nanopaSrticles incubation with diabetic cells was observed via western blot analysis to confirm insulin reversal ability. Fluorescence microscopic analysis with propidium iodide and acridine orange dyes showed the release of reactive oxygen species as a possible mechanism of the cytotoxic effect of MgO nanoparticles. It was inferred that the synergistic effect of the phytochemicals and MgO nanoparticles played a significant role in delivering enhanced insulin resistance reversal capability in adipose cells.

Biogenic nanoparticles: a comprehensive perspective in synthesis, characterization, application and its challenges

BACKGROUND

Translating the conventional scientific concepts into a new robust invention is a much needed one at a present scenario to develop some novel materials with intriguing properties. Particles in nanoscale exhibit superior activity than their bulk counterpart. This unique feature is intensively utilized in physical, chemical, and biological sectors. Each metal is holding unique optical properties that can be utilized to synthesize metallic nanoparticles. At present, versatile nanoparticles were synthesized through chemical and biological methods. Metallic nanoparticles pose numerous scientific merits and have promising industrial applications. But concerning the pros and cons of metallic nanoparticle synthesis methods, researchers elevate to drive the synthesis process of nanoparticles through the utilization of plant resources as a substitute for use of chemicals and reagents under the theme of green chemistry. These synthesized nanoparticles exhibit superior antimicrobial, anticancer, larvicidal, leishmaniasis, wound healing, antioxidant, and as a sensor. Therefore, the utilization of such conceptualized nanoparticles in treating infectious and environmental applications is a warranted one.

CONCLUSION

Green chemistry is a keen prudence method, in which bioresources is used as a template for the synthesis of nanoparticles. Therefore, in this review, we exclusively update the context of plant-based metallic nanoparticle synthesis, characterization, and applications in detailed coverage. Hopefully, our review will be modernizing the recent trends going on in metallic nanoparticles synthesis for the blooming research fraternities.

Δ6 fatty acid desaturases in polyunsaturated fatty acid biosynthesis: insights into the evolution, function with substrate specificities and biotechnological use

Δ6 fatty acid desaturases (FADS6) have different substrate specificities that impact the ratio of omega-6/omega-3 polyunsaturated fatty acids, which are involved in regulating multiple signalling pathways associated with various diseases. For decades, FADS6 with different substrate specificities have been characterized and the functions of these crucial enzymes have been investigated, while it remains enigmatic that the substrate specificities of FADS6 from various species have a huge difference. This review summarizes the substrate specificities of FADS6 in different species and reveals the underlying relationship. Further evaluation of biochemical properties has revealed that the FADS6 prefer linoleic acid that is more hydrophilic and stable. Domain-swapping and site-directed mutagenesis have been employed to delineate the regions and sites that affect the substrate specificities of FADS6. These analyses improve our understanding of the functions of FADS6 and offer information for the discovery of novel biological resources. KEY POINTS: • Outline of the excavation and identification of Δ6 fatty acid desaturases. • Overview of methods used to determine the pivotal resides of desaturases. • Application of substrate properties to generate specific fatty acids.

1-Cinnamoyltrichilinin from Melia azedarach Causes Apoptosis through the p38 MAPK Pathway in HL-60 Human Leukemia Cells

Acute myeloid leukemia (AML) is an aggressive type of human leukemia with a low survival rate, and its complete remission remains challenging. Although chemotherapy is the first-line treatment of AML, it exerts toxicity in noncancerous cells when used in high doses, thus necessitating the development of novel compounds with a high therapeutic window. This study aimed to investigate the anticancer effects of several compounds derived from the fruits of Melia azedarach (a tree with medicinal properties). Among them, 1-cinnamoyltrichilinin (CT) was found to strongly suppress the viability of HL-60 human leukemia cells. CT treatment induced apoptosis and increased nuclear fragmentation and fractional DNA content in HL-60 cells in a dose-dependent manner. CT induced phosphorylation of p38 mitogen-activated protein kinases (p38), though not of c-Jun N-terminal kinase (JNK) and extracellular signal-regulated kinase (ERK), and activated Bcl-2 family proteins towards the proapoptosis and cleavage of caspase-3 and poly (ADP-ribose) polymerase. Both CT-mediated apoptosis and apoptotic protein expression were reversed by treatment with the p38 inhibitor, thereby indicating the p38 pathway to be critical in CT-stimulated apoptosis. The results collectively indicated CT to suppress HL-60 survival by activating the p38 pathway and inducing apoptosis, hence being a novel potential therapeutic agent for AML.

Optimization of biogenic synthesis of silver nanoparticles from flavonoid-rich Clinacanthus nutans leaf and stem aqueous extracts

Background: Silver nanoparticles (AgNPs) are widely used in food industries, biomedical, dentistry, catalysis, diagnostic biological probes and sensors. The use of plant extract for AgNPs synthesis eliminates the process of maintaining cell culture and the process could be scaled up under a non-aseptic environment. The purpose of this study is to determine the classes of phytochemicals, to biosynthesize and characterize the AgNPs using Clinacanthus nutans leaf and stem extracts. In this study, AgNPs were synthesized from the aqueous extracts of C. nutans leaves and stems through a non-toxic, cost-effective and eco-friendly method. Results: The formation of AgNPs was confirmed by UV-Vis spectroscopy, and the size of AgNP-L (leaf) and AgNP-S (stem) were 114.7 and 129.9 nm, respectively. Transmission electron microscopy (TEM) analysis showed spherical nanoparticles with AgNP-L and AgNP-S ranging from 10 to 300 nm and 10 to 180 nm, with average of 101.18 and 75.38 nm, respectively. The zeta potentials of AgNP-L and AgNP-S were recorded at -42.8 and -43.9 mV. X-ray diffraction analysis matched the face-centred cubic structure of silver and was capped with bioactive compounds. Fourier transform infrared spectrophotometer analysis revealed the presence of few functional groups of phenolic and flavonoid compounds. These functional groups act as reducing agents in AgNPs synthesis. Conclusion: These results showed that the biogenically synthesized nanoparticles reduced silver ions to silver nanoparticles in aqueous condition and the AgNPs formed were stable and less toxic.

Natural Metallic Nanoparticles for Application in Nano-Oncology

Here, the various types of naturally synthesized metallic nanoparticles, which are essentially composed of Ce, Ag, Au, Pt, Pd, Cu, Ni, Se, Fe, or their oxides, are presented, based on a literature analysis. The synthesis methods used to obtain them most often involve the reduction of metallic ions by biological materials or organisms, i.e., essentially plant extracts, yeasts, fungus, and bacteria. The anti-tumor activity of these nanoparticles has been demonstrated on different cancer lines. They rely on various mechanisms of action, such as the release of chemotherapeutic drugs under a pH variation, nanoparticle excitation by radiation, or apoptotic tumor cell death. Among these natural metallic nanoparticles, one type, which consists of iron oxide nanoparticles produced by magnetotactic bacteria called magnetosomes, has been purified to remove endotoxins and abide by pharmacological regulations. It has been tested in vivo for anti-tumor efficacy. For that, purified and stabilized magnetosomes were injected in intracranial mouse glioblastoma tumors and repeatedly heated under the application of an alternating magnetic field, leading to the full disappearance of these tumors. As a whole, the results presented in the literature form a strong basis for pursuing the efforts towards the use of natural metallic nanoparticles for cancer treatment first pre-clinically and then clinically.

Inhibitory Effect of Eco-Friendly Naturally Synthesized Silver Nanoparticles from the Leaf Extract of Medicinal Detarium microcarpum Plant on Pancreatic and Cervical Cancer Cells

BACKGROUND

Recently, nanoparticle synthesis by eco-friendly methods has received tremendous attention due to the method advantages and also because of the application of the nanoparticles in cancer research. Therefore, in this study, we synthesized silver nanoparticles from Detarium microcarpum leaf phytochemicals and evaluated its inhibitory effect on pancreatic and cervical cancer cells.

MATERIALS AND METHODS

Silver nanoparticles (dAgNps) were synthesized by reacting phytochemicals of D. microcarpum leaves with silver nitrate for 12 hours. Cell viability assay was carried out to investigate the cytotoxic effect of dAgNps on HeLa and PANC-1 cells.

RESULTS

Scanning electron microscopy (SEM) and transmission electron microscopy(TEM) results revealed the average sizes of dAgNps are 81 nm and 84 nm respectively. The x-ray diffraction (XRD) pattern of dAgNps was similar to that of face centered cubic(fcc) structure of silver as reported by joint committee on powder diffraction standards (JCPDS) and fourier-transform infrared spectroscopy (FTIR) analysis showed that some phytochemicals of D. microcarpum such as polyphenols and flavonoids were likely involved in the reduction of Ag+ to form nanoparticles. Finally, cell viability assay revealed dAgNps inhibited PANC-1 and HeLa cell proliferations with IC50 values of 84 and 31.5 µg/ml respectively.

CONCLUSION

In conclusion, the synthesized nanoparticles from D. microcarpum leaves (dAgNps) have inhibitory effect on pancreatic and cervical cancer cells.

Biocompatible Nutmeg Oil-Loaded Nanoemulsion as Phyto-Repellent

Plant essential oils are widely used in perfumes and insect repellent products. However, due to the high volatility of the constituents in essential oils, their efficacy as a repellent product is less effective than that of synthetic compounds. Using a nanoemulsion as a carrier is one way to overcome this disadvantage of essential oils. Nutmeg oil-loaded nanoemulsion (NT) was prepared using a high speed homogenizer and sonicator with varying amounts of surfactant, glycerol, and distilled water. Using a phase diagram, different formulations were tested for their droplet size and insect repellent activity. The nanoemulsion containing 6.25% surfactant and 91.25% glycerol (NT 6) had the highest percentage of protection (87.81%) in terms of repellent activity among the formulations tested for the 8 h duration of the experiment. The droplet size of NT 6 was 217.4 nm, and its polydispersity index (PDI) was 0.248. The zeta potential value was -44.2 mV, and the viscosity was 2.49 Pa.s at pH 5.6. The in vitro release profile was 71.5%. When the cytotoxicity of NT 6 at 400 μg/mL was tested using the MTS assay, cell viability was 97.38%. Physical appearance and stability of the nanoemulsion improved with the addition of glycerol as a co-solvent. In summary, a nutmeg oil-loaded nanoemulsion was successfully formulated and its controlled release of the essential oil showed mosquito repellent activity, thus eliminating the disadvantages of essential oils.

Docetaxel-Loaded Disulfide Cross-Linked Nanoparticles Derived from Thiolated Sodium Alginate for Colon Cancer Drug Delivery

In this study, fluorescein-labelled wheat germ agglutinin (fWGA)-conjugated disulfide cross-linked sodium alginate nanoparticles were developed to specifically target docetaxel (DTX) to colon cancer cells. Different amounts of 3-mercaptopropionic acid (MPA) were covalently attached to sodium alginate to form thiolated sodium alginate (MPA1-5). These polymers were then self-assembled and air-oxidised to form disulfide cross-linked nanoparticles (MP1-5) under sonication. DTX was successfully loaded into the resulting MP1-5 to form DTX-loaded nanoparticles (DMP1-5). DMP2 had the highest loading efficiency (17.8%), thus was chosen for fWGA surface conjugation to form fWGA-conjugated nanoparticles (fDMP2) with a conjugation efficiency of 14.1%. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) analyses showed spherical nanoparticles, and an in vitro drug release study recorded a cumulative drug release of 48.6%. Dynamic light scattering (DLS) analysis revealed a mean diameter (MD) of 289 nm with a polydispersity index (PDI) of 0.3 and a zeta potential of -2.2 mV for fDMP2. HT-29 human colon cancer cells treated with fDMP2 showed lower viability than that of L929 mouse fibroblast cells. These results indicate that fDMP2 was efficiently taken up by HT-29 cells (29.9%). Fluorescence and confocal imaging analyses also showed possible internalisation of nanoparticles by HT-29 cells. In conclusion, fDMP2 shows promise as a DTX carrier for colon cancer drug delivery.

Synthesis of silver nanoparticles using a Mentha spicata extract and evaluation of its anticancer and cytotoxic activity

In this study, silver nanoparticles (NP) were synthesized by two methods: using an aqueous extract of Mentha spicata leaves and using citrate ions as stabilizing agent, and the cytotoxicity and anticancer activity of both NP were evaluated in vitro. The particles synthesized with the aqueous extract were spherical with a size ranging from 15 to 45 nm. These NP decreased cell viability in all of the cells studied; however, the IC₅₀ could only be estimated in the Chang liver cells (IC₅₀ = 21.37 µg/mL). These particles also decreased the generation of reactive oxygen species in Chang and SiHa cells. Additionally, the dispersions decreased the activity of caspase-3. There was no significant difference between the biological activities of the NP obtained with the aqueous extract and the NP synthesized using citrate ions. This study showed that an aqueous extract of M. spicata is an excellent alternative for the synthesis of silver NP. These NP showed cytotoxicity and anticancer activity in vitro. Although more experiments are required, the cell death occurs probably through a mechanism different from apoptosis.

Synthesis of Gold Nanoparticles Using Mimosa tenuiflora Extract, Assessments of Cytotoxicity, Cellular Uptake, and Catalysis

Synthesis of gold nanoparticles (AuNPs) with plant extracts has gained great interest in the field of biomedicine due to its wide variety of health applications. In the present work, AuNPs were synthesized with Mimosa tenuiflora (Mt) bark extract at different metallic precursor concentrations. Mt extract was obtained by mixing the tree bark in ethanol-water. The antioxidant capacity of extract was evaluated using 2,2-diphenyl-1-picrylhydrazyl and total polyphenol assay. AuNPs were characterized by transmission electron microscopy, X-ray diffraction, UV-Vis and Fourier transform infrared spectroscopy, and X-ray photoelectron spectrometry for functional group determination onto their surface. AuMt (colloids formed by AuNPs and molecules of Mt) exhibit multiple shapes with sizes between 20 and 200 nm. AuMt were tested on methylene blue degradation in homogeneous catalysis adding sodium borohydride. The smallest NPs (AuMt1) have a degradation coefficient of 0.008/s and reach 50% degradation in 190s. Cell viability and cytotoxicity were evaluated in human umbilical vein endothelial cells (HUVEC), and a moderate cytotoxic effect at 24 and 48 h was found. However, toxicity does not behave in a dose-dependent manner. Cellular internalization of AuMt on HUVEC cells was analyzed by confocal laser scanning microscopy. For AuMt1, it can be observed that the material is dispersed into the cytoplasm, while in AuMt2, the material is concentrated in the nuclear periphery.

Synthesis, characterization, and mechanistic studies of a gold nanoparticle-amphotericin B covalent conjugate with enhanced antileishmanial efficacy and reduced cytotoxicity

Background

Amphotericin B (AmB) as a liposomal formulation of AmBisome is the first line of treatment for the disease, visceral leishmaniasis, caused by the parasite Leishmania donovani. However, nephrotoxicity is very common due to poor water solubility and aggregation of AmB. This study aimed to develop a water-soluble covalent conjugate of gold nanoparticle (GNP) with AmB for improved antileishmanial efficacy and reduced cytotoxicity.

Methods

Citrate-reduced GNPs (~39 nm) were functionalized with lipoic acid (LA), and the product GNP-LA (GL ~46 nm) was covalently conjugated with AmB using carboxyl-to-amine coupling chemistry to produce GNP-LA-AmB (GL-AmB ~48 nm). The nanoparticles were characterized by dynamic light scattering, transmission electron microscopy (TEM), and spectroscopic (ultraviolet–visible and infrared) methods. Experiments on AmB uptake of macrophages, ergosterol depletion of drug-treated parasites, cytokine ELISA, fluorescence anisotropy, flow cytometry, and gene expression studies established efficacy of GL-AmB over standard AmB.

Results

Infrared spectroscopy confirmed the presence of a covalent amide bond in the conjugate. TEM images showed uniform size with smooth surfaces of GL-AmB nanoparticles. Efficiency of AmB conjugation was ~78%. Incubation in serum for 72 h showed <7% AmB release, indicating high stability of conjugate GL-AmB. GL-AmB with AmB equivalents showed ~5-fold enhanced antileishmanial activity compared with AmB against parasite-infected macrophages ex vivo. Macrophages treated with GL-AmB showed increased immunostimulatory T_h1 (IL-12 and interferon-γ) response compared with standard AmB. In parallel, AmB uptake was ~5.5 and ~3.7-fold higher for GL-AmB-treated (P<0.001) macrophages within 1 and 2 h of treatment, respectively. The ergosterol content in GL-AmB-treated parasites was ~2-fold reduced compared with AmB-treated parasites. Moreover, GL-AmB was significantly less cytotoxic and hemolytic than AmB (P<0.01).

Conclusion

GNP-based delivery of AmB can be a better, cheaper, and safer alternative than available AmB formulations.