Green Synthesis of Gold Nanoparticles Capped with Procyanidins from Leucosidea sericea as Potential Antidiabetic and Antioxidant Agents

Comparative Study of Callistemon citrinus (Bottlebrush) and Punica granatum (Pomegranate) Extracts for Sustainable Synthesis of Silver Nanoparticles and Their Oral Antimicrobial Efficacy

A comparative study was applied to investigate the potential of Callistemon citrinus (bottlebrush) flower extract (BBE) and Punica granatum (pomegranate) peel extracts (PPE) for the sustainable synthesis of the silver nanoparticles, Ag-BBE and Ag-PPE, respectively. The synthesis process of Ag NPs using the selected extracts was applied under optimized conditions. Hence, the effect of the selected plant's type on the different characteristics of the synthesized green Ag NPs was investigated. The UV-Vis spectroscopy revealed the presence of the characteristic silver peaks at 419 and 433 nm of the Ag-BBE and Ag-PPE, respectively. The XRD spectra reported the fcc phase formation of Ag NPs. The TEM results highlighted the morphological features of the synthesized Ag NPs. with a size range of 20-70 nm, and with 10-30 nm for Ag-BBE and Ag-PPE, correspondingly. The Raman spectra revealed characteristic silver bands in the Ag-PPE and reflected some bands related to the natural extract in the Ag-BBE sample. The antimicrobial activity and statistical analysis investigation were conducted against four selected oral pathogens (Staphylococcus aureus (SA), Candida albicans (CA), Staphylococcus epidermidis (S. epi), and Enterococcus faecalis (EF)). Both tested extracts, BBE, and PPE, revealed potential effectivity as reducing and capping agents for Ag NP green synthesis. However, the synthesized NPs demonstrated different features, depending on the used extract, reflecting the influence of the plant's biomolecules on the nanoparticles' properties.

Shining insights: Deciphering the biogenic synthesis of Ajuga bracteosa-mediated gold nanoparticles with advanced microscopy techniques

In this study, gold nanoparticles (AuNPs) were bioreduced from Ajuga bracteosa, a medicinal herb known for its therapeutic properties against various diseases. Different fractions of the plant extract were used, including the methanolic fraction (ABMF), the n-hexane fraction (ABHF), the chloroform fraction (ABCF), and the aqueous extract for AuNPs synthesis. The characterization of AuNPs was performed using UV-Vis spectrophotometry, FT-IR, XRD, EDX, and TEM. UV-Vis spectroscopy confirmed the formation of AuNPs, with peaks observed at 555 nm. FT-IR analysis indicated strong capping of phytochemicals on the surface of AuNPs, which was supported by higher total phenolic contents (TPC) and total flavonoid contents (TFC) in AuNPs. XRD results showed high crystallinity and a smaller size distribution of AuNPs. TEM analysis revealed the spherical shape of AuNPs, with an average size of 29 ± 10 nm. The biologically synthesized AuNPs exhibited superior antibacterial, antioxidant, and cytotoxic activities compared to the plant extract fractions. The presence of active biomolecules in A. bracteosa, such as neoclerodan flavonol glycosides, diterpenoids, phytoecdysone, and iridoid glycosides, contributed to the enhanced biological activities of AuNPs. Overall, this research highlights the potential of A. bracteosa-derived AuNPs for various biomedical applications due to their remarkable therapeutic properties and effective capping by phytochemicals. RESEARCH HIGHLIGHTS: This research underscores the growing significance of herbal medicine in contemporary healthcare by exploring the therapeutic potential of Ajuga bracteosa and gold nanoparticles (AuNPs). The study highlights the notable efficacy of A. bracteosa leaf extracts and AuNPs in treating bacterial infections, demonstrating their bactericidal effects on a range of strains. The anti-inflammatory properties of plant extracts and nanoparticles are evidenced through paw edema method suggesting their applicability in managing inflammatory conditions. These findings position A. bracteosa and AuNPs as potential candidates for alternative and effective approaches to modern medication.

Green Synthesis of Gold Nanoparticles Using Liquiritin and Other Phenolics from Glycyrrhiza glabra and Their Anti-Inflammatory Activity

Phenolic compounds are the main phytochemical constituents of many higher plants. They play an important role in synthesizing metal nanoparticles using green technology due to their ability to reduce metal salts and stabilize them through physical interaction/conjugation to the metal surface. Six pure phenolic compounds were isolated from licorice (Glycyrrhiza glabra) and employed in synthesizing gold nanoparticles (AuNPs). The isolated compounds were identified as liquiritin (1), isoliquiritin (2), neoisoliquiritin (3), isoliquiritin apioside (4), liquiritin apioside (5), and glabridin (6). The synthesized AuNPs were characterized using UV, zeta sizer, HRTEM, and IR and tested for their stability in different biological media. The phenolic isolates and their corresponding synthesized NP conjugates were tested for their potential in vitro cytotoxicity. The anti-inflammatory effects were investigated in both normal and inflammation-induced settings, where inflammatory biomarkers were stimulated using lipopolysaccharides (LPSs) in the RAW 264.7 macrophage cell line. LPS, functioning as a mitogen, promotes cell growth by reducing apoptosis, potentially contributing to observed outcomes. Results indicated that all six pure phenolic isolates inhibited cell proliferation. The AuNP conjugates of all the phenolic isolates, except liquiritin apioside (5), inhibited cell viability. LPS initiates inflammatory markers by binding to cell receptors and setting off a cascade of events leading to inflammation. All the pure phenolic isolates, except isoliquiritin, neoisoliquiritin, and isoliquiritin apioside inhibited the inflammatory activity of RAW cells in vitro.

Therapeutic strategy of biological macromolecules based natural bioactive compounds of diabetes mellitus and future perspectives: A systematic review

High blood glucose levels are a hallmark of the metabolic syndrome known as diabetes mellitus. More than 600 million people will have diabetes by 2045 as the global prevalence of the disease continues to rise. Contemporary antidiabetic drugs reduce hyperglycemia and its consequences. However, these drugs come with undesirable side effects, so it's encouraging that research into plant extracts and bioactive substances with antidiabetic characteristics is on the rise. Natural remedies are preferable to conventional anti-diabetic drugs since they are safer for the body, more affordable and have fewer potential adverse effects. Biological macromolecules such as liposomes, niosomes, polymeric nanoparticles, solid lipid nanoparticles, nanoemulsions and metallic nanoparticles are explored in this review. Current drug restrictions have been addressed, and the effectiveness of plant-based antidiabetic therapies has enhanced the merits of these methods. Plant extracts' loading capacity and the carriers' stability are the primary obstacles in developing plant-based nanocarriers. Hydrophilic, hydrophobic, and amphiphilic drugs are covered, and a brief overview of the amphipathic features of liposomes, phospholipids, and lipid nanocarriers is provided. Metallic nanoparticles' benefits and attendant risks are highlighted to emphasize their efficiency in treating hyperglycemia. Researchers interested in the potential of nanoparticles loaded with plant extracts as antidiabetic therapeutics may find the current helpful review.

From nature to nanotechnology: The interplay of traditional medicine, green chemistry, and biogenic metallic phytonanoparticles in modern healthcare innovation and sustainability

As we navigate the modern era, the intersection of time-honoured natural remedies and contemporary scientific approaches forms a burgeoning frontier in global healthcare. For generations, natural products have been foundational to health solutions, serving as the primary healthcare choice for 80% to 85% of the world's population. These herbal-based, nature-derived substances, significant across diverse geographies, necessitate a renewed emphasis on enhancing their quality, efficacy, and safety. In the current century, the advent of biogenic phytonanoparticles has emerged as an innovative therapeutic conduit, perfectly aligning with principles of environmental safety and scientific ingenuity. Utilizing green chemistry techniques, a spectrum of metallic nanoparticles including elements such as copper, silver, iron, zinc, and titanium oxide can be produced with attributes of non-toxicity, sustainability, and economic efficiency. Sophisticated herb-mediated processes yield an array of plant-originated nanomaterials, each demonstrating unique physical, chemical, and biological characteristics. These attributes herald new therapeutic potentials, encompassing antioxidants, anti-aging applications, and more. Modern technology further accelerates the synthesis of natural products within laboratory settings, providing an efficient alternative to conventional isolation methods. The collaboration between traditional wisdom and advanced methodologies now signals a new epoch in healthcare. Here, the augmentation of traditional medicine is realized through rigorous scientific examination. By intertwining ethical considerations, cutting-edge technology, and natural philosophy, the realms of biogenic phytonanoparticles and traditional medicine forge promising pathways for research, development, and healing. The narrative of this seamless integration marks an exciting evolution in healthcare, where the fusion of sustainability and innovation crafts a future filled with endless possibilities for human well-being. The research in the development of metallic nanoparticles is crucial for unlocking their potential in revolutionizing fields such as medicine, catalysis, and electronics, promising groundbreaking applications with enhanced efficiency and tailored functionalities in future technologies. This exploration is essential for harnessing the unique properties of metallic nanoparticles to address pressing challenges and advance innovations across diverse scientific and industrial domains.

Synthesis and characterization of TiO2 nanoparticles combined with geraniol and their synergistic antibacterial activity

BACKGROUND

The emergence of antibiotic resistance in pathogenic bacteria has become a global threat, encouraging the adoption of efficient and effective alternatives to conventional antibiotics and promoting their use as replacements. Titanium dioxide nanoparticles (TiO₂ NPs) have been reported to exhibit antibacterial properties. In this study, we synthesized and characterized TiO₂ NPs in anatase and rutile forms with surface modification by geraniol (GER).

RESULTS

The crystallinity and morphology of modified TiO₂ NPs were analyzed by UV/Vis spectrophotometry, X-ray powder diffraction (XRD), and scanning electron microscopy (SEM) with elemental mapping (EDS). The antimicrobial activity of TiO₂ NPs with geraniol was assessed against Staphylococcus aureus, methicillin-resistant Staphylococcus aureus (MRSA), and Escherichia coli. The minimum inhibitory concentration (MIC) values of modified NPs ranged from 0.25 to 1.0 mg/ml against all bacterial strains, and the live dead assay and fractional inhibitory concentration (FIC) supported the antibacterial properties of TiO₂ NPs with GER. Moreover, TiO₂ NPs with GER also showed a significant decrease in the biofilm thickness of MRSA.

CONCLUSIONS

Our results suggest that TiO₂ NPs with GER offer a promising alternative to antibiotics, particularly for controlling antibiotic-resistant strains. The surface modification of TiO₂ NPs by geraniol resulted in enhanced antibacterial properties against multiple bacterial strains, including antibiotic-resistant MRSA. The potential applications of modified TiO₂ NPs in the biomedical and environmental fields warrant further investigation.

Green-Synthesized Silver Nanoparticles: Antifungal and Cytotoxic Potential for Further Dental Applications

Fungal infections caused by Candida albicans (C. albicans) are one of the most prevalent types of oral disorders in the elderly. It has been reported that drug resistance to fungal pathogens poses a severe risk to global healthcare systems and public health. Therefore, the goal of this work is to investigate the cytotoxic and antifungal properties of silver nanoparticles (AgNPs) produced using three different natural extracts: Berzelia lanuginose, Helichrysum cymosum, and Searsia crenata. According to the UV-Vis results, the synthesized AgNPs via B. lanuginose, H. cymosum, and S. crenata show surface plasmonic resonance (SPR) peaks at 430, 440, and 428 nm, respectively. HR-TEM revealed different shapes for the nanoparticles within the size ranges of 16-20, 31-60, and 57-72 nm for B. lanuginose, H. cymosum, and S. crenata, respectively. Using a human oral fibroblast cell line, the cytotoxicity of both AgNPs and plant extracts was tested at concentrations of 0.007, 0.012, 0.025, and 0.062 mg/mL (buccal mucosa fibroblasts). The antifungal activity showed growth inhibition zones of approximately 18 mm, 18.67 mm, and 18.33 mm for the AgNPs conjugated with B. lanuginose, H. cymosum, and S. crenata, respectively. For the studied samples, the minimum inhibitory concentration (MIC₅₀) was less than 0.015 mg/mL. The AgNPs exhibited antifungal activity that was concentration- and size-dependent. The results of this study offer new insights into the cytotoxicity and antifungal activity of the green-synthesized AgNPs.

Evaluation of innovative polyvinyl alcohol/ alginate/ green palladium nanoparticles composite scaffolds: Effect on differentiated human dental pulp stem cells into osteoblasts

Three-dimensional (3D) scaffolds are attracting great concern for bone tissue engineering applications. However, selecting an appropriate material with optimal physical, chemical, and mechanical properties is considered a great challenge. The green synthesis approach is essential to avoid the production of harmful by-products through textured construction, sustainable, and eco-friendly procedures. This work aimed at the implementation of natural green synthesized metallic nanoparticles for the development of composite scaffolds for dental applications. In this study, innovative hybrid scaffolds of polyvinyl alcohol/alginate (PVA/Alg) composite loaded with various concentrations of green palladium nanoparticles (Pd NPs) have been synthesized. Various characteristic analysis techniques were used to investigate the synthesized composite scaffold's properties. The SEM analysis revealed impressive microstructure of the synthesized scaffolds dependent on the Pd NPs concentration. The results confirmed the positive effect of Pd NPs doping on the sample stability over time. The synthesized scaffolds were characterized by the oriented lamellar porous structure. The results confirmed the shape stability, without pores breakdown during the drying process. The XRD analysis confirmed that doping with Pd NPs does not affect the crystallinity degree of the PVA/Alg hybrid scaffolds. The mechanical properties results (up to 50 MPa) confirmed the remarkable effect of Pd NPs doping and its concentration on the developed scaffolds. The MTT assay results showed that the incorporation of Pd NPs into the nanocomposite scaffolds is necessary for increasing cell viability. According to the SEM results, the scaffolds with Pd NPs provided the differentiated grown osteoblast cells with enough mechanical support and stability and the cells had a regular form and were highly dense. In conclusion, the synthesized composite scaffolds expressed suitable biodegradable, osteoconductive properties, and the ability to construct 3D structures for bone regeneration, making them a potential option for treating critical deficiencies of bone.

One-pot green synthesis of gold nanoparticles using Sarcophyton crassocaule, a marine soft coral: Assessing biological potentialities of antibacterial, antioxidant, anti-diabetic and catalytic degradation of toxic organic pollutants

Marine bio-resources are being extensively researched as a priceless supply of substances with therapeutic potential. This work report the first time attempt made towards the green synthesis of gold nanoparticles (AuNPs) using the aqueous extract of marine soft coral (SCE), Sarcophyton crassocaule. The synthesis was conducted under optimized conditions and the visual coloration of reaction mixture changed from yellowish to ruby red at 540 nm. The electron microscopic (TEM, SEM) studies exhibited spherical and oval shaped SCE-AuNPs in the size ranges of 5–50 nm. The organic compounds present in SCE were primarily responsible for the biological reduction of gold ions validated by FT-IR while the zeta potential confirmed the overall stability of SCE-AuNPs. The synthesized SCE-AuNPs exhibited variety of biological efficacies like antibacterial, antioxidant and anti-diabetic in nature. The biosynthesized SCE-AuNPs demonstrated remarkable bactericidal efficacy against clinically significant bacterial pathogens with inhibition zones of mm. Additionally, SCE-AuNPs exhibited greater antioxidant capacity in terms of DPPH: 85 ± 0.32% and RP: 82 ± 0.41%). The ability of enzyme inhibition assays to inhibit α-amylase (68 ± 0.21%) and α-glucosidase (79 ± 0.2%) was quite high. The study also highlighted the spectroscopic analysis of the biosynthesized SCE-AuNPs' catalytic effectiveness of 91% in the reduction processes of the perilous organic dyes, exhibiting pseudo-first order kinetics.

Development of portable sensor for the detection of bacteria: effect of gold nanoparticle size, effective surface area, and interparticle spacing upon sensing interface

In this study, systematic development of a portable sensor for the rapid detection of Escherichia coli (E. coli) and Exiguobacterium aurantiacum (E. aurantiacum) was reported. A conductive glass was utilized as a substrate and developed the electrode patterns on it. Trisodium citrate (TSC) and chitosan-stabilized gold nanoparticles (AuNPs) (CHI-AuNP-TSC) and chitosan-stabilized AuNPs (CHI-AuNP) were synthesized and utilized as a sensing interface. The morphology, crystallinity, optical properties, chemical structures, and surface properties of immobilized AuNPs on the sensing electrodes were investigated. The sensing performance of the fabricated sensor was evaluated by using an electrochemical method to observe the current changes in cyclic voltammetric responses. The CHI-AuNP-TSC electrode has higher sensitivity toward E. coli than CHI-AuNP with a limit of detection (LOD) of 1.07 CFU/mL. TSC in the AuNPs synthesis process played a vital role in the particle size, the interparticle spacing, the sensor's effective surface area, and the presence of CHI around AuNPs, thus enhancing the sensing performance. Moreover, post-analysis of the fabricated sensor surface exhibited the sensor stability and the interaction between bacteria and the sensor surface. The sensing results showed a promising potential for rapid detection using a portable sensor for various water and food-borne pathogenic diseases.

Antidiabetic potential of Gymnemic acid mediated gold nanoparticles (Gym@AuNPs) on Streptozotocin-induced diabetic rats-An implication on in vivo approach

Gymnemic acid is glycosides of triterpene with recognized and valuable applications for several chronic diseases, mainly diabetics. Despite this, it requires a delivery system in order to range its therapeutic target due to its limited solubility and bioavailability. Therefore, the Gymnemic acid mediated gold nanoparticles (Gym@AuNPs) was synthesised by eco-friendly approach. The synthesised Gym@AuNPs was confirmed by the colour change from light yellow to a deep ruby red. UV - visible spectroscopy results showed a strong narrow peak at 530 nm, confirming the controlled synthesis of monodispersed Gym@AuNPs. The reduction potential of standard Gymnemic acid (Gym) on synthesis of Gym@AuNPs was confirmed by using HPLC analysis. The spherical shaped Gym@AuNPs was observed by FESEM and HR-TEM studies with average size of 48.52 ± 5.53 nm. The XRD analysis exhibited a face-centered cubic (FCC) crystalline nature of Gym@AuNPs. The in vivo antidiabetic activity of Gym and Gym@AuNPs were validated using Streptozotocin induced diabetic Albino wistar rats. The Gym@AuNPs and Gym were regulates the glucose and lipid levels in experimental animals. The histopathology outcomes shown that the Gym@AuNPs were restoration of pancreatic islets cells in the animals. This investigation demonstrated that the Gym@AuNPs had the potential anti-diabetic properties.

Highly efficient photothermal branched Au-Ag nanoparticles containing procyanidins for synergistic antibacterial and anti-inflammatory immunotherapy

Periodontitis is an inflammatory disease caused by bacterial infection. Excessive immune response and high levels of reactive oxygen species (ROS) further lead to the irreversible destruction of surrounding tissues. Developing new antimicrobial materials that regulate the immune system to resist inflammation can effectively treat periodontal inflammation. A nanoplatform integrating Ag⁺, photothermal therapy (PTT), and procyanidins (PC) for precision antibacterial and synergistic immunotherapy for periodontitis was proposed. This work loaded PC into AuAg nanoparticles, and the resulting nanocomposite was named AuAg-PC. PTT can effectively remove pathogenic bacteria, but high temperatures can cause tissue damage. Ag⁺ contributes to the preparation of a nanoparticle branched structure that improves the photothermal efficiency and helps PTT achieve an excellent antibacterial effect and avoid periodontal tissue damage. PC regulates host immunity by eliminating intracellular ROS, inhibiting inflammatory factors, and regulating macrophage polarisation in periodontal disease sites. It enhances the host's resistance to bacterial inflammation. AuAg-PC exerted an excellent anti-inflammatory effect and promoted tissue repair in animal periodontal inflammation models. Hence, AuAg-PC significantly combats periodontal pathogens and shows great application potential in the photothermal-assisted immunotherapy of periodontitis. This design provided a new controllable and efficient treatment platform for controlling persistent inflammation infection and regulating immunity.

The Antioxidant and In Vitro Wound Healing Activity of Cotyledon orbiculata Aqueous Extract and the Synthesized Biogenic Silver Nanoparticles

The synthesis of silver nanoparticles using biogenic methods, particularly plants, has led to the discovery of several effective nanoparticles. In many instances, plant-derived silver nanoparticles have been shown to have more activity than the plant extract which was used to synthesize the nanoparticles. Silver nanoparticles have been successfully synthesized using the medicinal plant, Cotyledon orbiculata. This is a shrub found in the Western Cape province of South Africa. It has a long history of use in traditional medicine in the treatment of wounds and skin infections. The C. orbiculata synthesized silver nanoparticles (Cotyledon-AgNPs) were reported to have good antimicrobial and anti-inflammatory activities; however, their wound-healing properties have not been determined. This study aimed to determine the wound healing activity of Cotyledon-AgNPs using the scratch assay. Gene expression studies were also done to determine the nanoparticles' mechanism of action. The Cotyledon-AgNPs showed good antioxidant, growth-promoting and cell migration properties. Gene expression studies showed that the C. orbiculata water extract and Cotyledon-AgNPs promoted wound healing by upregulating genes involved in cell proliferation, migration and growth while downregulating pro-inflammatory genes. This confirms, for the first time that a water extract of C. orbiculata and silver nanoparticles synthesized from this extract are good wound-healing agents.

Biomedical Applications of Biosynthesized Gold Nanoparticles from Cyanobacteria: an Overview

Recently there had been a great interest in biologically synthesized nanoparticles (NPs) as potential therapeutic agents. The shortcomings of conventional non-biological synthesis methods such as generation of toxic byproducts, energy consumptions, and involved cost have shifted the attention towards green syntheses of NPs. Among noble metal NPs, gold nanoparticles (AuNPs) are the most extensively used ones, owing to the unique physicochemical properties. AuNPs have potential therapeutic applications, as those are synthesized with biomolecules as reducing and stabilizing agent(s). The green method of AuNP synthesis is simple, eco-friendly, non-toxic, and cost-effective with the use of renewable energy sources. Among all taxa, cyanobacteria have attracted considerable attention as nano-biofactories, due to cellular uptake of heavy metals from the environment. The cellular bioactive pigments, enzymes, and polysaccharides acted as reducing and coating agents during the process of biosynthesis. However, cyanobacteria-mediated AuNPs have potential biomedical applications, namely, targeted drug delivery, cancer treatment, gene therapy, antimicrobial agent, biosensors, and imaging.

An Overview of Herbal-Based Antidiabetic Drug Delivery Systems: Focus on Lipid- and Inorganic-Based Nanoformulations

Diabetes is a metabolic pathology with chronic high blood glucose levels that occurs when the pancreas does not produce enough insulin or the body does not properly use the insulin it produces. Diabetes management is a puzzle and focuses on a healthy lifestyle, physical exercise, and medication. Thus far, the condition remains incurable; management just helps to control it. Its medical treatment is expensive and is to be followed for the long term, which is why people, especially from low-income countries, resort to herbal medicines. However, many active compounds isolated from plants (phytocompounds) are poorly bioavailable due to their low solubility, low permeability, or rapid elimination. To overcome these impediments and to alleviate the cost burden on disadvantaged populations, plant nanomedicines are being studied. Nanoparticulate formulations containing antidiabetic plant extracts or phytocompounds have shown promising results. We herein aimed to provide an overview of the use of lipid- and inorganic-based nanoparticulate delivery systems with plant extracts or phytocompounds for the treatment of diabetes while highlighting their advantages and limitations for clinical application. The findings from the reviewed works showed that these nanoparticulate formulations resulted in high antidiabetic activity at low doses compared to the corresponding plant extracts or phytocompounds alone. Moreover, it was shown that nanoparticulate systems address the poor bioavailability of herbal medicines, but the lack of enough preclinical and clinical pharmacokinetic and/or pharmacodynamic trials still delays their use in diabetic patients.

Gold nanocrystals: optical properties, fine-tuning of the shape, and biomedical applications

Noble metal nanomaterials with special physical and chemical properties have attracted considerable attention in the past decades. In particular, Au nanocrystals (NCs), which possess high chemical inertness and unique surface plasmon resonance (SPR), have attracted extensive research interest. In this study, we review the properties and preparation of Au NCs with different morphologies as well as their important applications in biological detection. The preparation of Au NCs with different shapes by many methods such as seed-mediated growth method, seedless synthesis, polyol process, ultrasonic method, and hydrothermal treatment has already been introduced. In the seed-mediated growth method, the influence factors in determining the final shape of Au NCs are discussed. Au NCs, which show significant size-dependent color differences are proposed for preparing biological probes to detect biomacromolecules such as DNA and protein, while probe conjugate molecules serves as unique coupling agents with a target. Particularly, Au nanorods (NRs) have some unique advantages in the application of biological probes and photothermal cancer therapy compared to Au nanoparticles (NPs).

A Review on the Delivery of Plant-Based Antidiabetic Agents Using Nanocarriers: Current Status and Their Role in Combatting Hyperglycaemia

Diabetes mellitus is a prevalent metabolic syndrome that is associated with high blood glucose levels. The number of diabetic patients is increasing every year and the total number of cases is expected to reach more than 600 million worldwide by 2045. Modern antidiabetic drugs alleviate hyperglycaemia and complications that are caused by high blood glucose levels. However, due to the side effects of these drugs, plant extracts and bioactive compounds with antidiabetic properties have been gaining attention as alternative treatments for diabetes. Natural products are biocompatible, cheaper and expected to cause fewer side effects than the current antidiabetic drugs. In this review, various nanocarrier systems are discussed, such as liposomes, niosomes, polymeric nanoparticles, nanoemulsions, solid lipid nanoparticles and metallic nanoparticles. These systems have been applied to overcome the limitations of the current drugs and simultaneously improve the efficacy of plant-based antidiabetic drugs. The main challenges in the formulation of plant-based nanocarriers are the loading capacity of the plant extracts and the stability of the carriers. A brief review of lipid nanocarriers and the amphipathic properties of phospholipids and liposomes that encapsulate hydrophilic, hydrophobic and amphiphilic drugs is also described. A special emphasis is placed on metallic nanoparticles, with their advantages and associated complications being reported to highlight their effectiveness for treating hyperglycaemia. The present review could be an interesting paper for researchers who are working in the field of using plant extract-loaded nanoparticles as antidiabetic therapies.

Inorganic Nanomaterials Versus Polymer-Based Nanoparticles for Overcoming Neurodegeneration

Neurodegenerative disorders (NDs) affect a great number of people worldwide and also have a significant socio-economic impact on the aging population. In this context, nanomedicine applied to neurological disorders provides several biotechnological strategies and nanoformulations that improve life expectancy and the quality of life of patients affected by brain disorders. However, available treatments are limited by the presence of the blood–brain barrier (BBB) and the blood–cerebrospinal fluid barrier (B–CSFB). In this regard, nanotechnological approaches could overcome these obstacles by updating various aspects (e.g., enhanced drug-delivery efficiency and bioavailability, BBB permeation and targeting the brain parenchyma, minimizing side effects). The aim of this review is to carefully explore the key elements of different neurological disorders and summarize the available nanomaterials applied for neurodegeneration therapy looking at several types of nanocarriers. Moreover, nutraceutical-loaded nanoparticles (NPs) and synthesized NPs using green approaches are also discussed underling the need to adopt eco-friendly procedures with a low environmental impact. The proven antioxidant properties related to several natural products provide an interesting starting point for developing efficient and green nanotools useful for neuroprotection.

Evaluation of antioxidant activity of extracts from Leucosidea sericea

Introduction: Leucosidea sericea finds applications in the treatment of herpes and HIV.

Objective: The aim of the current study was to evaluate the antioxidant activity and determine the total flavonoid contents (TFCs) and total phenolic contents (TPCs) of hexane, chloroform, ethyl acetate, acetone and methanol crude extracts obtained from leaves and stem-bark of L. sericea.

Methods: Maceration and hot solvent extraction methods were used to obtain various crude extracts. DPPH and ferric reducing power assays were used to evaluate the antioxidant activity. Colorimetric aluminium chloride and Folin-Ciocalteu methods were used to determine the TFCs and TPCs, respectively.

Results: The methanol leaf extract showed highest radical scavenging activity of 82.00±0.93% at a concentration of 3000 µg/ml followed by ethyl acetate leaf extract and methanol stem-bark extract with 79.40±5.21 and 75.16±1.15%, respectively. Acetone stem-bark extract showed highest ferric reducing power of 0.539±0.004 at 700 nm at a concentration of 100 µg/ml followed by hexane leaf extract and hexane stem-bark extract with 0.474±0.014 and 0.437±0.013 at 700 nm, respectively. Ethyl acetate stem-bark extract showed highest TFCs of 655.6±0.1111 mg QE/g of DW of the extract followed by acetone stem-bark extract with 450.0±0.00711 mg QE/g of DW of the extract. Acetone stem-bark extract showed highest TPCs of 891.9±0.657 mg TAE/g of the DW of extract followed by methanol stem-bark extract with 878.3±0.029 mg TAE/g of DW of the extract.

Conclusion: The antioxidant activity of various solvent extracts from leaves and stem-bark of L. sericea was evaluated. L. sericea could be a source of potent antioxidants.

Procyanidins and Their Therapeutic Potential against Oral Diseases

Procyanidins, as a kind of dietary flavonoid, have excellent pharmacological properties, such as antioxidant, antibacterial, anti-inflammatory and anti-tumor properties, and so they can be used to treat various diseases, including Alzheimer’s disease, diabetes, rheumatoid arthritis, tumors, and obesity. Given the low bioavailability of procyanidins, great efforts have been made in drug delivery systems to address their limited use. Nowadays, the heavy burden of oral diseases such as dental caries, periodontitis, endodontic infections, etc., and their consequences on the patients’ quality of life indicate a strong need for developing effective therapies. Recent years, plenty of efforts are being made to develop more effective treatments. Therefore, this review summarized the latest researches on versatile effects and enhanced bioavailability of procyanidins resulting from innovative drug delivery systems, particularly focused on its potential against oral diseases.

Phytochemical Profiling and Isolation of Bioactive Compounds from Leucosidea sericea (Rosaceae)

In the study, ultraperformance liquid chromatography-quadrupole time-of-flight-mass spectrometry analysis of Leucosidea sericea leaf and stem extracts led to the identification of various classes of compounds. Further chromatographic purifications resulted in the isolation of 22 compounds that consisted of a new triterpenoid named leucosidic acid A (1), an acetophenone derivative 2, a phloroglucinol derivative 3, three chromones 4-6, seven pentacyclic triterpenoids 7-13, a phytosterol glucoside 14, a flavonoid 15, and seven flavonoid glycosides 16-22. Nineteen of these compounds including the previously undescribed triterpenoid 1 are isolated for the first time from L. sericea. The structures of the isolated compounds were assigned based on their high-resolution mass spectrometry and nuclear magnetic resonance data. Some of the isolated triterpenoids were evaluated for inhibitory activity against α-amylase, α-glucosidase, and pancreatic lipase. Of the tested compounds, 1-hydroxy-2-oxopomolic acid (7) and pomolic acid (13) showed higher potency on α-glucosidase than acarbose, which is used as a positive control in this study. The two compounds inhibited α-glucosidase with IC₅₀ values of 192.1 ± 13.81 and 85.5 ± 6.87 μM, respectively.

Nanoformulation of plant-based natural products for type 2 diabetes mellitus: From formulation design to therapeutic applications

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Inorganic element based nanoformulations were prominent in the delivery drug leads.

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Polymer and lipid based nanoformulations are emerging as novel formulations.

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Majority of investigations on nanoherbal formulations were on in vitro models.

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Proper glycemic control was an important property in nanoherbalformulations.

Background

Herbal remedies are used to manage type 2 diabetes mellitus (type 2 DM) as the sole treatment or as a complementary therapy. Limitations of herbal remedies, such as poor stability and limited absorption, impede their development as therapeutic agents, which could be overcome by nanoformulations.

Objectives

This review attempts to summarize the studies reported between 2009 and 2020 in the development of medicinal plant-based nanoformulations for the management of type 2 DM, discuss formulation methods, mechanisms of action, and identify gaps in the literature to conduct future research on nanoparticle-based herbal treatment options targeting type 2 DM.

Methods

To retrieve articles published between January 2009 and December 2020, the electronic databases PubMed, Science Direct, and Google Scholar were searched with the keywords nanoparticle, plant, and diabetes in the entire text. Peer-reviewed research articles on herbal nanoformulations published in English-language based on in vitro and/or in vivo models of type 2 DM and/or its complications were included. The literature search and selection of titles/abstracts were carried out independently by 2 authors. The list of full-text articles was selected considering inclusion and exclusion criteria, with the agreement of all the authors.

Results

Among the reported studies, 68% of the studies were on inorganic herbal nanoformulations, whereas 17% and 8% were of polymer-based and lipid-based herbal nanoformulations, respectively. Some of the important biological properties of nanoformulations included improvement in glycemic control and insulin levels, inhibition of the formation of advanced glycation end products, and regeneration of pancreatic β cells. The aforementioned properties were observed by screening nanoformulations using in vitro cellular and noncellular models, as well as in vivo animal models of type 2 DM studied for acute or subacute durations. Only 2 clinical trials with patients with diabetes were reported, indicating the need for further research on medicinal plant-based nanoformulations as a therapeutic option for the management of type 2 DM.

Conclusions

Medicinal plant extracts and isolated compounds have been nanoformulated using various methods. The properties of the nanoformulations were found superior to those of the corresponding herbal extracts and isolated compounds. At both the preclinical and clinical levels, there are a number of poorly explored research areas in the development and bioactivity assessment of herbal nanoformulations. (Curr Ther Res Clin Exp. 2022; 83:XXX–XXX) © 2022 Elsevier HS Journals, Inc.

Green synthesis of gold nanaoparticles using Delphinium Chitralense tuber extracts, their characterization and enzyme inhibitory potential

Green synthesis has been introduced as an alternative to chemical synthesis due to the serious consequences. Metal nanoparticles synthesized through green approach have different pharmaceutical, medical and agricultural applications. The present study followed a green and simple route for the preparation of potentially bioactive gold nanoparticles (Au NPs). Au NPs were prepared via green synthesis approach using crude basic alkaloidal portion of the tuber of Delphinium chitralense. The green synthesized Au NPs were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD) fourier transform infrared (FTIR), and UV-Visible spectrophotometer. Morphological analysis shows that Au NPs have cubic geometry with different sizes. UV-Vis spectroscopic analysis confirmed the synthesis of Au NPs while XRD proved their pure crystalline phase. The Au NPs showed promising dose dependent inhibition of both AChE and BChE as compared to the crude as well as standard drug.

Effects of Natural Brown Cotton Bleached Gauze on Wound Healing

Natural brown cotton has favorable antibacterial and antioxidant properties. In this study, we explored the effect of gauze made from natural brown cotton after scouring and bleaching on wound healing in rats. In this work, a control experiment was adopted. The control group used absorbent cotton gauze, and the experimental group utilized natural brown cotton bleached gauze. The materials were applied to rat models to explore the effects of the two dressings on wound healing. By analyzing the wound healing state of rats, calculating the healing rate, and combining the pathological HE staining, Masson staining, and CD31 immunohistochemical staining, the results showed that both gauzes have positive effects on the wound healing of the rats. Moreover, compared with the control group, the wound healing rate of rats in the experimental group increased by 14.81%, the number of inflammatory cells decreased by 12.93%, the number of new blood vessels increased by 6.88%, the growth rate of the granulation tissue area was 10.76%, the step-up rate of the area occupied by collagen was 33.71%, and the increase rate of optical density value was 10.00%. This study found that natural brown cotton bleached gauze has a better effect on wound healing than ordinary absorbent cotton gauze, and can be used as medical dressings.

Recent advances on therapeutic potentials of gold and silver nanobiomaterials for human viral diseases

Viral diseases are prominent among the widely spread infections threatening human well-being. Real-life clinical successes of the few available therapeutics are challenged by pathogenic resistance and suboptimal delivery to target sites. Nanotechnology has aided the design of functionalised and non-functionalised Au and Ag nanobiomaterials through physical, chemical and biological (green synthesis) methods with improved antiviral efficacy and delivery. In this review, innovative designs as well as interesting antiviral activities of the nanotechnology-inclined biomaterials of Au and Ag, reported in the last 5 years were critically overviewed against several viral diseases affecting man. These include influenza, respiratory syncytial, adenovirus, severe acute respiratory syndromes (SARS), rotavirus, norovirus, measles, chikungunya, HIV, herpes simplex virus, dengue, polio, enterovirus and rift valley fever virus. Notably identified among the nanotechnologically designed promising antiviral agents include AuNP-M2e peptide vaccine, AgNP of cinnamon bark extract and AgNP of oseltamivir for influenza, PVP coated AgNP for RSV, PVP-AgNPs for SARS-CoV-2, AuNRs of a peptide pregnancy-induce d hypertension and AuNP nanocarriers of antigen for MERS-CoV and SARS-CoV respectively. Others are AgNPs of collagen and Bacillus subtilis for rotavirus, AgNPs labelled Ag30-SiO 2 for murine norovirus in water, AuNPs of Allium sativum and AgNPs of ribavirin for measles, AgNPs of Citrus limetta and Andrographis Paniculata for Chikungunya, AuNPs of efavirenz and stavudine, and AgNPs-curcumin for HIV, NPAuG3-S8 for HSV, AgNPs of Moringa oleifera and Bruguiera cylindrica for dengue while AgNPs of polyethyleneimine and siRNA analogues displayed potency against enterovirus. The highlighted candidates are recommended for further translational studies towards antiviral therapeutic designs.

Biosynthesis of Gold Nanoisotrops Using Carallia brachiata Leaf Extract and Their Catalytic Application in the Reduction of 4-Nitrophenol

The past decade has observed a significant surge in efforts to discover biological systems for the fabrication of metal nanoparticles. Among these methods, plant-mediated synthesis has garnered sizeable attention due to its rapid, cost-effective, environmentally benign single-step procedure. This study explores a step-wise, room-temperature protocol for the synthesis of gold nanoparticles (AuNPs) using Carallia brachiata, a mangrove species from the west coast of Peninsular Malaysia. The effects of various reaction parameters, such as incubation time, metal ion concentration, amount of extract and pH, on the formation of stable colloids were monitored using UV-visible (UV-Vis) absorption spectrophotometry. Our findings revealed that the physicochemical properties of the AuNPs were significantly dependent on the pH. Changing the pH of the plant extract from acidic to basic appears to have resulted in a blue-shift in the main characteristic feature of the surface plasmon resonance (SPR) band, from 535 to 511 nm. The high-resolution-transmission electron microscopy (HR-TEM) and field emission scanning electron microscopy (FESEM) images revealed the morphologies of the AuNPs synthesized at the inherent pH, varying from isodiametric spheres to exotic polygons and prisms, with sizes ranging from 10 to 120 nm. Contrarily, an optimum pH of 10 generated primarily spherical-shaped AuNPs with narrower size distribution (8–13 nm). The X-ray diffraction (XRD) analysis verified the formation of AuNPs as the diffraction patterns matched well with the standard value of a face-centered cubic (FCC) Au lattice structure. The Fourier-transform infrared (FTIR) spectra suggested that different functional groups are involved in the biosynthetic process, while the phytochemical test revealed a clear role of the phenolic compounds. The reduction of 4-nitrophenol (4-NP) was selected as the model reaction for evaluating the catalytic performance of the green-synthesized AuNPs. The catalytic activity of the small, isotropic AuNPs prepared using basic aqueous extract was more effective than the nanoanisotrops, with more than 90% of 4-NP conversion achieved in under an hour with just 3 mg of the nanocatalyst.

Biogenic proficient synthesis of (Au-NPs) via aqueous extract of Red Dragon Pulp and seed oil: Characterization, antioxidant, cytotoxic properties, anti-diabetic anti-inflammatory, anti-Alzheimer and their anti-proliferative potential against cancer cell lines

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Novel Green synthesis of Au-NPs using Dragon fruit pulp and seed oil extract for the first time.

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Use of green and safer protocol for synthesis of Au-NPs further demonstrate that we can apply green chemistry protocols to reduce environmental pollution and disposal of waste toxicants.

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FTIR analysis confirmed the capping of therapeutically potent phytochemicals which are of great use in applied field especially medical.

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Significant Anti-diabetic, Anti-inflammatory, Anti-Alzheimer and Cytotoxic potential of biosynthesized Au-NPs create a new idea and shifting experts to treat cancerous cell lines.

Gold nanoparticles with tiny sizes and biostability are particularly essential and are employed in a variety of biomedical applications. Using a reducing agent and a stabilising agent to make gold nanoparticles has been reported in a number of studies. Gold nanoparticles with a particle size of 25.31 nm were synthesized in this study utilising Hylocereus polyrhizus (Red Pitaya) extract, which functions as a reducing and stabilising agent. The extract of Red Pitaya is said to be a powerful antioxidant and anti-cancer agent. Because of its substantial blood biocompatibility and physiological stability, green production of gold nanoparticles with H. polyrhizus fruit extract is an alternative to chemical synthesis and useful for biological and medical applications. The formation and size distribution of gold nanoparticles were confirmed by HPLC, UV-Vis spectrophotometer, X-ray diffraction (XRD), Dynamic light scattering (DLS), Zeta potential, Transmission electron microscopy (TEM), Fourier transformed infrared spectroscopy (FTIR), Energy dispersive X-ray (EDX) and X-ray photoelectron spectroscopy (XPS). The well-analysed NPs were used in various biological assays, including anti-diabetic, anti-inflammatory, anti-Alzheimer, and antioxidant (DPPH), and cytotoxic investigations. The NPs also showed a dose-dependent cytotoxic activity against HCT-116, HepG2 and MCF-7 cell lines, with IC₅₀ of 100 µg/mL for HCT-116 cells, 155 µg/mL for HepG2, and for MCF-7 cells the value was 165 µg/mL respectively. Finally, the outstanding biocompatibility of Au-NPs has led to the conclusion that they are a promising choice for various biological applications.

Enhancing the efficacy of Hypericum perforatum in the treatment of an experimental model of multiple sclerosis using gold nanoparticles: an in vivo study

Objective

Hypericum perforatum is a herbal medicine used in traditional medicine for the treatment of depression due to its antidepressant and anti-inflammatory activities. Therefore, we evaluated the therapeutic efficacy of H. perforatum extract (HPE) in combination with gold nanoparticles (HPE-GNP) against experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis.

Materials and Methods

EAE was induced in C57BL/6 mice with subcutaneous injection of MOG35-55 emulsified in complete Freund's adjuvant, and intraperitoneal pertussis toxin. Mice were treated with drugs in free (HPE) and nano-form (HPE-GNP) preparations. Splenocytes were isolated from all mice and the level of inflammatory and anti-inflammatory cytokines were evaluated by ELISA. The expression of T cells' transcription factors was also assessed using Real-Time PCR.

Results

Clinical score was reduced after HPE-GNP treatment. This change was associated with a decrease in the incidence and infiltration of inflammatory cells into the central nervous system. Additionally, treatment with HPE-GNP decreased the level of pro-inflammatory cytokines (IFN-γ, IL-17A and IL-6) and increased anti-inflammatory cytokines (TGF-β, IL-10 and IL-4). The real-time analysis revealed a decrease in the level of T-bet and ROR-γt but an increase in FoxP3 and GATA3 expression.

Conclusion

The current study demonstrated that HPE-GNP could potentially reduce clinical and pathological complications of EAE, but laboratory data showed that HPE-GNP was significantly more effective than HPE in the treatment of EAE.

Catalytic and Medical Potential of a Phyto-Functionalized Reduced Graphene Oxide-Gold Nanocomposite Using Willow-Leaved Knotgrass

In the current study, a simple, environmentally friendly, and cost-effective reduced graphene oxide-gold nanoparticle (rGO-AuNP) nanocomposite was successfully phytosynthesized using the aqueous leaf extract of a common weed found on the Nile banks, Persicaria salicifolia, for the first time. The phytosynthesis of rGO-AuNPs was first confirmed via the color transformation from brown to black as well as throughvarious techniques such as transmission electron microscopy (TEM) and Raman spectroscopy. Two UV-vis peaks at 275 and 530 nm were observed for the nanocomposite with a typical particle size of mostly spherical AuNPs of 15-20 nm. However, other shapes were occasionally detected including rods, triangles, and rhomboids. Existing phytoconstituents such as flavonoids and glycosides in the plant extract were suggested to be responsible for the phytosynthesis of rGO-AuNPs. The excellent catalytic efficacy of rGO-AuNPs against MB degradation was confirmed, and a high antibacterial efficiency against Escherichia coli and Klebsiella pneumonia was also confirmed. Promising antioxidant performance of rGO-AuNPs was also proved. Furthermore, it was concluded that rGO-AuNPs acquired higher efficiency than AuNPs synthesized from the same plant extract in all of the studied applications.

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.

Cytotoxic Effects of Phytomediated Silver and Gold Nanoparticles Synthesised from Rooibos (Aspalathus linearis), and Aspalathin

The green chemistry approach has continuously been applied for the synthesis of functional nanomaterials to reduce waste, environmental hazards, and the use of toxic chemicals among other reasons. Bioactive natural compounds have been found great potential in this regard and are used to improve the stability, activity, and biodistribution of metal nanoparticles (MNPs). Aspalathin (ASP) from Aspalathus linearis (rooibos) has a well-defined pharmacological profile and functional groups capable of both reducing and capping agents in the synthesis of metallic nanoparticles (NP). This study provides the first report of the phytomediated synthesis of gold and silver nanoparticles (AuNPs/AgNPs) via ASP and the green rooibos (GR) extract. The study demonstrated a green chemistry approach to the biosynthesis of nanoparticles of GR-AuNPs, ASP-AuNPs, GR-AgNPs, and ASP-AgNPs. The results showed that GR and ASP could act both as reducing and stabilising agents in the formation of crystalline, with different shapes and dispersity of NPs in the ranges of 1.6-6.7 nm for AgNPs and 7.5-12.5 nm for the AuNPs. However, the ASP NPs were less stable in selected biogenic media compared to GR NPs and were later stabilised with polyethene glycol. The cytotoxicity studies showed that GR-AgNPs were the most cytotoxic against SH-SY5Y and HepG2 with IC₅₀ 108.8 and 183.4 μg/mL, respectively. The cellular uptake analysis showed a high uptake of AuNPs and indicated that AgNPs of rooibos at a lower dose (1.3-1.5 μg/mL) is favourable for its anticancer potential. This study is a contribution to plant-mediated metallic nanoparticles using a pure single compound that can be further developed for targeted drug delivery for cancer cells treatments in the coming years.

Recent update on nano-phytopharmaceuticals in the management of diabetes

Due to changed lifestyle and other reasons, diabetes has become one of the common metabolic disorder of the globe. Numerous therapeutic options are available, which controls the plasma glucose levels. However, most of the drugs are associated with some undesired side effects. Owing to the side effects and enhanced understanding of the phytochemicals, an inclination toward herbal medicine is seen in the population. These herbal products are also associated with concerns like poor aqueous solubility, compromised permeation, and a low degree of bioavailability. So, the emergence of nanotechnology in the herbal medicine is required to nullify the associated concerns of conventional antidiabetic drugs. The present review aims to compile the literature available for the nano-interventions pertinent to herbal products for diabetes management.

Bioremediation and pharmacological applications of gold nanoparticles synthesized from plant materials

Nanotechnology and nanoscience are gaining remarkable attention in this era due to their distinctive properties and multi applications. Gold nanoparticles (AuNPs) is one of the most relevant metal nanoparticles with enormous applications in various field of research and industries. The demand for AuNPs is increasing rapidly. Extensive awareness has been allotted to the development of novel approaches for the synthesis of AuNPs with quality morphological properties using biological sources due to the limitations associated with the chemical and physical methods. Several factors such as contact time, temperature, pH of solution media, concentration of gold precursors and volume of plant extract influences the synthesis, characterization and applications of AuNPs. Characterization of synthesized AuNPs is important in evaluating the morphological properties of AuNPs since the morphological properties of AuNPs affect their potential use in various applications. This review highlights various methods of synthesizing AuNPs, parameters influencing the biosynthesis of AuNPs from plant extract, several techniques used for AuNPs characterization and their potential in bioremediation and biomedical applications.

Green Silver and Gold Nanoparticles: Biological Synthesis Approaches and Potentials for Biomedical Applications

The nanomaterial industry generates gigantic quantities of metal-based nanomaterials for various technological and biomedical applications; however, concomitantly, it places a massive burden on the environment by utilizing toxic chemicals for the production process and leaving hazardous waste materials behind. Moreover, the employed, often unpleasant chemicals can affect the biocompatibility of the generated particles and severely restrict their application possibilities. On these grounds, green synthetic approaches have emerged, offering eco-friendly, sustainable, nature-derived alternative production methods, thus attenuating the ecological footprint of the nanomaterial industry. In the last decade, a plethora of biological materials has been tested to probe their suitability for nanomaterial synthesis. Although most of these approaches were successful, a large body of evidence indicates that the green material or entity used for the production would substantially define the physical and chemical properties and as a consequence, the biological activities of the obtained nanomaterials. The present review provides a comprehensive collection of the most recent green methodologies, surveys the major nanoparticle characterization techniques and screens the effects triggered by the obtained nanomaterials in various living systems to give an impression on the biomedical potential of green synthesized silver and gold nanoparticles.

Biosynthesis, Characterization, and Biological Activities of Procyanidin Capped Silver Nanoparticles

In this study, procyanidin dimers and Leucosidea sericea total extract (LSTE) were employed in the synthesis of silver nanoparticles (AgNPs) and characterized by ultraviolet-visible (UV-Visible) spectroscopy, high-resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED), X-ray diffraction (XRD), and dynamic light scattering (DLS) techniques. AgNPs of about 2–7 nm were obtained. DLS and stability evaluations confirmed that the AgNPs/procyanidins conjugates were stable. The formed nanoparticles exhibited good inhibitory activities against the two enzymes studied. The IC₅₀ values against the amylase enzyme were 14.92 ± 1.0, 13.24 ± 0.2, and 19.13 ± 0.8 µg/mL for AgNPs coordinated with LSTE, F1, and F2, respectively. The corresponding values for the glucosidase enzyme were 21.48 ± 0.9, 18.76 ± 1.0, and 8.75 ± 0.7 µg/mL. The antioxidant activities were comparable to those of the intact fractions. The AgNPs also demonstrated bacterial inhibitory activities against six bacterial species. While the minimum inhibitory concentrations (MIC) of F1-AgNPs against Pseudomonas aeruginosa and Staphylococcus aureus were 31.25 and 15.63 µg/mL respectively, those of LSTE-AgNPs and F2-AgNPs against these organisms were both 62.50 µg/mL. The F1-AgNPs demonstrated a better bactericidal effect and may be useful in food packaging. This research also showed the involvement of the procyanidins as reducing and capping agents in the formation of stable AgNPs with potential biological applications.

Innovative Therapies and Nanomedicine Applications for the Treatment of Alzheimer's Disease: A State-of-the-Art (2017-2020)

The field of nanomedicine is constantly expanding. Since the first work dated in 1999, almost 28 thousand articles have been published, and more and more are published every year: just think that only in the last five years 20,855 have come out (source PUBMED) including original research and reviews. The goal of this review is to present the current knowledge about nanomedicine in Alzheimer’s disease, a widespread neurodegenerative disorder in the over 60 population that deeply affects memory and cognition. Thus, after a brief introduction on the pathology and on the state-of-the-art research for NPs passing the BBB, special attention is placed to new targets that can enter the interest of nanoparticle designers and to new promising therapies. The authors performed a literature review limited to the last three years (2017–2020) of available studies with the intention to present only novel formulations or approaches where at least in vitro studies have been performed. This choice was made because, while limiting the sector to nanotechnology applied to Alzheimer, an organic census of all the relevant news is difficult to obtain.

Antibacterial, anti-efflux, anti-biofilm, anti-slime (exopolysaccharide) production and urease inhibitory efficacies of novel synthesized gold nanoparticles coated Anthemis atropatana extract against multidrug- resistant Klebsiella pneumoniae strains

In this study, the antibacterial, anti-efflux, anti-biofilm, anti-slime (exopolysaccharide) production and urease inhibitory efficacies of green synthesized gold nanoparticles (AuNPs) coated Anthemis atropatana extract against multidrug- resistant (MDR) Klebsiella pneumoniae strains were evaluated. The green synthesized AuNPs were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffractometer (XRD), particle size distribution, zeta potential and Fourier-transform infrared spectroscopy (FTIR). Then, antibacterial, anti-slime (exopolysaccharide) production, anti-biofilm and anti-efflux activities of AuNPs were investigated using micro-dilation, Congored agar, microtiter plate and MIC of ethidium bromide methods, respectively. Subsequently, the expression of mrkA, wzm and acrB genes was evaluated using quantitative Real-Time PCR (qRT-PCR). The synthesized AuNPs exhibited antibacterial activity against MDR strains of K. pneumoniae (minimum inhibitory concentration (MIC) of 6.25-50 µg/ml), as well as showed significant anti-slime (exopolysaccharide) production, anti-biofilm and anti-efflux activities against MDR strains. AuNPs showed significant inhibition against jack-bean urease and down-regulated the expression of mrkA, wzm and acrB genes. Moreover, the in vitro cytotoxic activity confirmed by MTT assay on the HEK-293 normal cell line showed negligible cytotoxicity. Thus, the present study suggests the potential use of AuNPs in the development of novel therapeutics for the prevention of biofilm-associated K. pneumoniae infections.