Green Synthesis and Characterization of Highly Stable Silver Nanoparticles from Ethanolic Extracts of Fruits of Annona muricata

Regulating Enzyme Catalysis by Tailored Silver Nanocrystals Fabricated with Holigarna arnottiana-Synthesis, Characterization, and Performance Optimization

Modification of catalytic expression of enzymes and regulating their in vivo activity are the goals of novel treatment strategies. A green synthetic nanostructured silver with potent trypsin inhibitory properties has not yet been developed, despite the fact that silver nanoparticles possess unique properties that allow them to efficiently block enzymes. The present study demonstrates for the first time a facile, safe, economic, and eco-friendly synthetic route for silver nanoparticles using an aqueous extract of Holigarna arnottiana bark engineered to interact with trypsin and hinder its activity effectively. The studies carried out to examine the interaction between these biofabricated AgNPs (HaAgNPs) and trypsin by UV-visible spectrophotometry and FTIR spectroscopy suggest that the formation of trypsin-HaAgNP complex is responsible for diminishing the catalytic efficiency of trypsin. In vivo studies on Aedes aegypti larval serum support these instrumental results of HaAgNP-induced trypsin inhibition and proves its application as a biopesticide. It is noteworthy that the bioengineered HaAgNPs were also found to have good inhibition potential against pepsin and urease as well. A variety of methods have been employed to characterize the synthesized biocompatible HaAgNPs and it possesses a characteristic absorption maximum of 420 nm. Their shelf life of above 7 years is noticeable, since none of the reported green synthesized AgNPs possess a shelf life of more than 1 year. Altogether, this work demonstrates that biofabricated HaAgNPs are multifunctional and cost-resilient biological tools that can be used as enzyme regulators possessing antioxidant, antimicrobial, and insecticidal features.

Optimization of silver nanoparticles synthesis via Plackett-Burman experimental design: in vitro assessment of their efficacy against oxidative stress-induced disorders

Nanoparticles possess remarkable biological activities owing to their small size and large surface-to-volume ratio. Given the increasing adoption of environmentally sustainable practices in silver nanoparticle (AgNP) fabrication, this study presents a simple lab-scale green synthesis of AgNPs using banana peels. Large amounts of banana peels are disposed off in Pakistan every day. As the fruit is available throughout the year and contains many active components with potent biological activities, we aimed to synthesize silver nanoparticles using its peel, through an energy-efficient and inexpensive route. The synthesis was optimized according to the Plackett-Burman design (PDB) of experiments, which helped identify significant factors and saved time and resources. For characterization, UV-Vis spectroscopy and SEM-EDX analysis were performed, revealing spherical particles in the 45-65 nm size range. To investigate functional groups, FT-IR analysis was performed, revealing the presence of N-C[double bond, length as m-dash]O amide I bonds of proteins, C-H bonds of tannins and C-O bonds involved in the capping and stabilization of nanoparticles. The free radical scavenging property of banana peel-mediated silver nanoparticles (BP-AgNPs) was studied against 2,2-diphenyl-1-picrylhydrazyl (DPPH), and the antioxidant potential was found to be 79% at 500 μg mL-1 concentration. The efficacy of BP-AgNPs with respect to certain biological activities were studied through anti-inflammatory assays, which demonstrated better results compared to a standard drug, and an anti-glycation assay, wherein only 4% of AGEs were formed, demonstrating 96% of AGE inhibition in vitro. The findings not only demonstrated the effectiveness of the PBD approach but also highlighted the potent property of BP-AgNPs against disorders associated with oxidative stress.

Phytonano silver for cosmetic formulation- synthesis, characterization, and assessment of antimicrobial and antityrosinase potential

Novel formulations of silver nanoparticles remain exciting if it is applicable for cosmetic purposes. This study proposes a value-added brand-new nanomaterial for improving skin complexion by inhibiting melanin development. This work aims to develop cost effective, efficient, natural silver nanoparticles phytomediated by aqueous extract of leaf sheath scales of Cocos nucifera (Cn-AgNPs) having potential as tyrosinase inhibitors hindering melanin synthesis. The formation of Cn-AgNPs was assessed spectrophotometrically and confirmed by the sharp SPR spectrum at 425 nm. The chemical composition profiling was characterized by X-ray diffraction (XRD) and Fourier Transform Infrared (FTIR) spectroscopy. The morphology was confirmed by Field Emission Scanning Electron Microscopy (FESEM) and the thermal stability was assessed by Thermogravimetric analysis (TGA). Pharmacological application studies supported the materialization of Cn-AgNPs with significant antityrosinase potential and considerably improved antibacterial and antioxidant properties. Cn-AgNPs showed potential antibacterial effects against gram-positive and negative strains, including prominent infectious agents of the skin. Antioxidant capacity was confirmed with an IC50 of 57.8 μg/mL by DPPH radical scavenging assay. Furthermore, in vitro melanin content determination was performed using SK-MEL cells. Cell line studies proved that Cn-AgNPs decrease the melanin content of cells. The IC50 value obtained was 84.82 μg/mL. Hence Cn-AgNPs is proposed to be acting as a whitening agent through lessening cellular melanin content and as a significant inhibitor of tyrosinase activity. The antioxidant properties and antibacterial effects can contribute to skin rejuvenation and can prevent skin infections as well. This evidence proposes the development of a new nanostructured pharmaceutical and cosmetic formulation from Cocos nucifera leaf sheath scales.

Recycling of silver nanoparticles from electronic waste via green synthesis and application of AgNPs-chitosan based nanocomposite on textile material

The main thrust of this project is the fabrication of silver nanoparticles (AgNPs) from electronic waste (PCB board) and applying it on 100% cotton fabric as an antimicrobial agent. The nanoparticle formation of silver was done by green synthesis way using an aqueous leaf extract of Eichhornia crassipes. Furthermore, chitosan was also applied to the fabric with silver nanoparticles by coating. FTIR and SEM tests characterized the fabricated silver nanoparticles, and antimicrobial tests were followed by the disc diffusion method. The SEM analysis showed an average particle size of 76.91 nm. The FTIR analysis showed the successful reduction of silver nanoparticles and the bonding with chitosan and cellulose. Besides, the EDX reports confirmed the existence of AgNPs by indicating a strong signal in the silver region. In addition, SEM characteristics analysis confirmed the uniform deposition of silver nanoparticles. Finally, the antimicrobial property was tested against gram-positive (Staphylococcus aureus) and gram-negative (Escherichia coli) bacteria. The antimicrobial result was found satisfactory in the case of green-synthesized recycled AgNPs. However, the effectiveness was not observed to be higher than green-synthesized pure AgNPs. In this study, the zone of inhibition of AgNPs was also compared to the reference antibiotics Ciprofloxacin.

Mapping the Progress in Surface Plasmon Resonance Analysis of Phytogenic Silver Nanoparticles with Colorimetric Sensing Applications

Nanotechnology is gaining enormous attention as the most dynamic research area in science and technology. It involves the synthesis and applications of nanomaterials in diverse fields including medical, agriculture, textiles, food technology, cosmetics, aerospace, electronics, etc. Silver nanoparticles (AgNPs) have been extensively used in such applications due to their excellent physicochemical, antibacterial, and biological properties. The use of plant extract as a biological reactor is one of the most promising solutions for the synthesis of AgNPs because this process overcomes the drawbacks of physical and chemical methods. This review article summarizes the plant-mediated synthesis process, the probable reaction mechanism, and the colorimetric sensing applications of AgNPs. Plant-mediated synthesis parameters largely affect the surface plasmon resonance (SPR) characteristic due to the changes in the size and shape of AgNPs. These changes in the size and shape of plant-mediated AgNPs are elaborately discussed here by analyzing the surface plasmon resonance characteristics. Furthermore, this article also highlights the promising applications of plant-mediated AgNPs in sensing applications regarding the detection of mercury, hydrogen peroxide, lead, and glucose. Finally, it describes the future perspective of plant-mediated AgNPs for the development of green chemistry.

Encapsulation of AgNPs in a Lignin Isocyanate Film: Characterization and Antimicrobial Properties

Lignin isolated from agricultural residues is a promising alternative for petroleum-based polymers as feedstocks in development of antimicrobial materials. A polymer blend based on silver nanoparticles and lignin-toluene diisocyanate film (AgNPs-Lg-TDIs) was generated from organosolv lignin and silver nanoparticles (AgNPs). Lignin was isolated from Parthenium hysterophorus using acidified methanol and used to synthesize lignin capped silver nanoparticles. Lignin-toluene diisocyanate film (Lg-TDI) was prepared by treating lignin (Lg) with toluene diisocyanate (TDI) followed by solvent casting to form films. Functional groups present and thermal properties of the films were evaluated using Fourier-transform infrared spectrophotometry (FT-IR), thermal gravimetry (TGA), and differential scanning calorimetry (DSC). Scanning electron microscopy (SEM), UV-visible spectrophotometry (UV-Vis), and Powder X-ray diffractometry (XRD) were used to assess the morphology, optical properties, and crystallinity of the films. Embedding AgNPs in the Lg-TDI films increased the thermal stability and the residual ash during thermal analysis, and the presence of powder diffraction peaks at 2θ = 20, 38, 44, 55, and 58⁰ in the films correspond to lignin and silver crystal planes (111). SEM micrographs of the films revealed the presence of AgNPs in the TDI matrix with variable sizes of between 50 to 250 nm. The doped films had a UV radiation cut-off at 400 nm as compared to that of undoped films, but they did not exhibit significant antimicrobial activity against selected microorganisms.

Evaluation and remediation protocol of selected organochlorine pesticides and heavy metals in industrial wastewater using nanoparticles (NPs) in Nigeria

Limited knowledge of the level of contaminants in industrial wastewater within the Nigerian states together with the global challenge of water supply have compelled our investigation into the analyses and removal of organochlorine pesticides (OCPs) and heavy metal contents in industrial wastewater. Wastewater samples were collected from 13 industries across five states in Nigeria. The OCPs content of the samples was extracted, cleaned up and analysed using gas chromatography-mass spectrometry. The results indicate that the mean concentrations of the OCPs in the effluent samples ranged from 1.76 ng L^-1 (Dieldrin) to 0.89 ng L^-1 (endrin). Cadmium (Cd), chromium (Cr) and lead (Pb) were evaluated in all the effluent water samples. The results show that the average concentrations of the heavy metal ions in the effluent samples ranged from 0.008 ± 0.003 mg L^-1 (Cd) to 2.215 ± 0.841 mg L^-1 (Pb). For the removal of the identified contaminants, biomagnetite nanoparticles (BioMag), magnetite nanoparticles (MagNPs), biomagnetite-CMC nanocomposite (BioMag-CMC) and magnetite-CMC nanocomposite (MagNPs-CMC) were synthesised and characterised using Braunauer-Emmett-Teller (BET), Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) and high resolution-transmission electron microscopy (HR-TEM). This study demonstrates the successful application of nanoparticles (NPs) and nanocomposites in the removal of OCPs and heavy metal ions in industrial effluents. The routine assessment and continuous removal become important to attain a state of clean and healthy aquatic ecosystem due to rapid industrial and technological advances.

Effect of the physicochemical changes in the antimicrobial durability of green synthesized silver nanoparticles during their long-term storage

It is generally recognized that the stability of nanoparticles (NPs) has a great impact on their potential biological applications. Despite this, very few studies have investigated the change in toxicity of NPs over time but none has studied the periodic physicochemical changes contributing to it. To address this, we analyzed the effects of long-term storage on the physicochemical changes of green synthesized silver nanoparticles (AgNPs) that directly influences their antimicrobial durability. Light-induced slow synthesis of AgNPs was carried out using Saraca asoca aqueous leaf extract. The synthesis was optimized with respect to parameters known to play a major role in the long-term stability of AgNPs: pH, temperature, light exposure time, AgNO₃ concentration, extract proportion in the reaction mixture and storage conditions. Freshly synthesized AgNPs were characterized and then stored under optimized conditions. UV-vis spectrophotometry, AAS, conventional TEM and HR-TEM along with EDX spectroscopy were used at regular intervals to test the physicochemical properties that influence their long-term stability. Broth dilution assay was used to test antimicrobial activity of AgNPs against Escherichia coli and Staphylococcus aureus. Under dark storage conditions at room temperature, the AgNPs exhibited excellent stability with very good dispersity, throughout the study period of 18 months, despite the particles undergoing physicochemical changes in largescale. AgNPs exhibited sufficient antimicrobial activity against both strains tested. Due to the stronger stabilizing effect of the extract, we observed the lowest inhibition of E. coli and S. aureus by the freshly synthesized and 15 day old AgNPs; however, the inhibition rate escalated after a month and the highest rate of inhibition was observed with the particles between 2 months to 6 months of storage. After 6 months, we observed the particles losing their antimicrobial potential gradually, that lasted throughout the rest of our study period. This observation was in accord with the physicochemical changes that AgNPs were undergoing with time. By deepening our understanding of the changes in the physicochemical properties of green synthesized AgNPs over time, this study contributes to the development of more effective, durable, and potent AgNPs.

A Review on Annona muricata and Its Anticancer Activity

Simple Summary

Cancer is becoming more prevalent, raising concerns regarding how well current treatments work. Cancer patients frequently seek alternative treatments to surgery, chemotherapy, and radiation therapy. The use of medicinal plants in both preventative and curative healthcare is widely acknowledged. The compounds of graviola have shown promise as possible cancer-fighting agents and could be used to treat cancer. This review discusses bioactive metabolites present in graviola and their role in affecting the growth and death of different cancer cell types and the molecular mechanism of how it works to downregulate anti-apoptotic genes and the genes involved in pro-cancer metabolic pathways. Also, it reviews how simultaneously increasing the expression of genes promotes apoptosis and causes cancer cells to die so that the active phytochemicals found in graviola could be used as a promising anti-cancer agent.

Abstract

The ongoing rise in the number of cancer cases raises concerns regarding the efficacy of the various treatment methods that are currently available. Consequently, patients are looking for alternatives to traditional cancer treatments such as surgery, chemotherapy, and radiotherapy as a replacement. Medicinal plants are universally acknowledged as the cornerstone of preventative medicine and therapeutic practices. Annona muricata is a member of the family Annonaceae and is familiar for its medicinal properties. A. muricata has been identified to have promising compounds that could potentially be utilized for the treatment of cancer. The most prevalent phytochemical components identified and isolated from this plant are alkaloids, phenols, and acetogenins. This review focuses on the role of A. muricata extract against various types of cancer, modulation of cellular proliferation and necrosis, and bioactive metabolites responsible for various pharmacological activities along with their ethnomedicinal uses. Additionally, this review highlights the molecular mechanism of the role of A. muricata extract in downregulating anti-apoptotic and several genes involved in the pro-cancer metabolic pathways and decreasing the expression of proteins involved in cell invasion and metastasis while upregulating proapoptotic genes and genes involved in the destruction of cancer cells. Therefore, the active phytochemicals identified in A. muricata have the potential to be employed as a promising anti-cancer agent.

Biosynthesis of silver nanoparticles with antibacterial, antioxidant, anti-inflammatory properties and their burn wound healing efficacy

The current study aims to develop a novel burn wound ointment consisting of sheep’s tail ointment loaded with AgNP. The AgNP in the ointment serves as an antibacterial, antioxidant and anti-inflammatory agent. The AgNP was developed via the biological method with the assistance of the medicinal plant Rhodiola rosea. The characterization of AgNP was assessed using UV-Vis spectroscopy, FTIR, Zeta Potential, XRD, PCCS, SEM, and EDX techniques. The formation of AgNP was confirmed by UV-Vis spectrum at the absorbance of ∼430 nm, and the biomolecules responsible for reducing and capping the AgNP were characterized by FTIR analysis. The stability of AgNP was determined with Zeta potential, which revealed a highly stable colloidal solution with a surface charge of −68.38 ± 3.4 mV. The synthesized AgNP had a face-centered cubic structure with a crystallite size of 23 nm and average grain size of 67.5 nm. The SEM image showed a fairly monodisperse 20 nm-sized spherical-shaped AgNP. The synthesized AgNP contained high purity of the silver, and a low concentration of AgNP inhibited both Gram-positive and Gram-negative bacteria. Moreover, the scavenging activity of AgNP was investigated using DPPH and H₂O₂ scavenging assay, and the results revealed a dose-dependent antioxidant activity with the highest activity at a concentration of 450 μg/ml. Finally, the burn wound healing effect was evaluated by applying the AgNP-loaded ointment to the wound site of BALB/c mice. The in-vivo studies confirmed that AgNP-loaded ointment reduced the wound size, decreased the epidermis layer, and lowered mast cell migration compared to untreated burn wounds. And the synthesized AgNP regulated both pro-inflammatory and anti-inflammatory gene expression, thereby promoting burn wound closure on BALB/c mice. The developed AgNP-loaded ointment has the potential to be applied in the biomedical field.

Fungal-derived Selenium Nanoparticles and Their Potential Applications in Electroless Silver Coatings for Preventing Pin-tract Infections

Pin-tract infections (PTIs) are a common complication of external fixation of fractures and current strategies for preventing PTIs have proven to be ineffective. Recent advances show that the use of anti-infection coatings with local antibacterial activity may solve this problem. Selenium has been considered as a promising anti-infection agent owing to its antibacterial and antibiofilm activities. In this study, selenium nanoparticles (SeNPs) were synthesized via a cost-effective fungi-mediated biorecovery approach and demonstrated excellent stability and homogeneity. To investigate their anti-infection potential, the SeNPs were doped in silver coatings through an electroless plating process and the silver–selenium (Ag–Se) coatings were tested for antibacterial and antibiofilm properties against Staphylococcus aureus F1557 and Escherichia coli WT F1693 as well as corrosion resistance in simulated body fluid. It was found that the Ag–Se coating significantly inhibited S.aureus growth and biofilm formation on the surface, reducing 81.2% and 59.7% of viable bacterial adhesion when compared with Ag and Ag–PTFE-coated surfaces after 3 days. The Ag–Se coating also exhibited improved corrosion resistance compared with the Ag coating, leading to a controlled release of Ag⁺, which in turn reduced the risk of cytotoxicity against hFOBs. These results suggest that the fungal-derived SeNPs may have potential in use as implant coatings to prevent PTIs.

Histopathological evaluation of amino acid capped silver nanoconjugates in albino mice

Various molecules may modify the surface chemistry of commonly used nanomaterials (NMs), resulting in the synthesis of novel and safer NMs. The current study was delineated to evaluate the in vivo toxicity profiling of the silver nanoconjugates (AgNCs) conjugated with different amino acids. The L-glycine capped-AgNCs exhibited toxicity and caused tissue damage, while L-cystine- and L-tyrosine-capped AgNCs showed protective effects against cadmium-induced toxicity. L-cystine-capped AgNCs performed well as compared to other amino-acid AgNCs. The level of serum creatinine, alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase and blood urea increased (p < 0.05) in G2, G3 and G5 in comparison to G1 (control group), while an increase in bilirubin for G2 was statistically non-significant (p > 0.05). The ALT and AST elevated (p < 0.05) in G4; however, other serological parameters in G4 and G6 did not show any noticeable change in their values. Histological analysis showed disturbed and deformed cellular structures in liver and kidney tissues of G2, G3 and G5. However, G4 and G6 samples demonstrated minute changes in comparison to G1. It is concluded that L-cystine- and L-tyrosine-capped AgNCs exhibited protective effects and should be tested further for developing safer nanoconjugates for biomedical uses.

Green Synthesis of Metal and Metal Oxide Nanoparticles: Principles of Green Chemistry and Raw Materials

Increased request for metal and metal oxide nanoparticles nanoparticles has led to their large-scale production using high-energy methods with various toxic solvents. This cause environmental contamination, thus eco-friendly “green” synthesis methods has become necessary. An alternative way to synthesize metal nanoparticles includes using bioresources, such as plants and plant products, bacteria, fungi, yeast, algae, etc. “Green” synthesis has low toxicity, is safe for human health and environment compared to other methods, meaning it is the best approach for obtaining metal and metal oxide nanoparticles. This review reveals 12 principles of “green” chemistry and examples of biological components suitable for “green” synthesis, as well as modern scientific research of eco-friendly synthesis methods of magnetic and metal nanoparticles. Particularly, using extracts of green tea, fruits, roots, leaves, etc., to obtain Fe3O4 NPs. The various precursors as egg white (albumen), leaf and fruit extracts, etc., can be used for the „green” synthesis of spinel magnetic NPs. “Green” nanoparticles are being widely used as antimicrobials, photocatalysts and adsorbents. “Green” magnetic nanoparticles demonstrate low toxicity and high biocompatibility, which allows for their biomedical application, especially for targeted drug delivery, contrast imaging and magnetic hyperthermia applications. The synthesis of silver, gold, platinum and palladium nanoparticles using extracts from fungi, red algae, fruits, etc., has been described.

Synthesis of Ultrastable and Bioconjugable Ag, Au, and Bimetallic Ag_Au Nanoparticles Coated with Calix[4]arenes

Compared to gold nanoparticles, silver nanoparticles are largely underexploited for the development of plasmonic nanosensors. This is mainly due to their easy chemical degradation through oxidation, poor colloidal stability, and usually broad size distribution after synthesis, which leads to broad localized surface plasmon resonance bands. Coatings based on polymers such as poly(ethylene glycol) (PEG) or poly(vinylpyrrolidone) (PVP) and plant extracts have been used for the stabilization of AgNPs; however, these thick coatings are not suitable for sensing applications as they isolate the metallic core. The examples of stable AgNPs coated with a thin organic layer remain scarce in comparison to their gold counterparts. In this work, we present a convenient one-step synthesis strategy that allows to obtain unique gold, silver, and bimetallic NPs that combine all of the properties required for biosensing applications. The NPs are stabilized by a tunable calix[4]arene-based monolayer obtained through the reduction of calix[4]arene-tetradiazonium salts. These multidentate ligands are of particular interest as (i) they provide excellent colloidal and chemical stabilities to the particles thanks to their anchoring to the surface via multiple chemical bonds, (ii) they allow the subsequent (bio)conjugation of (bio)molecules under mild conditions, and (iii) they allow a control over the composition of mixed coating layers. Ag and Ag_Au nanoparticles of a high stability are obtained, opening perspectives for development of numerous biosensing applications.

Green synthesis and antibiofilm potential of Silver Nanoparticles loaded with Narcissus tazetta L. Extract

Bacterial infections are the leading cause of mortality, due to the paucity of effective drugs. This study aimed to synthesize AgNPs loaded with fresh leaves & bulbs extracts of Narcissus tazetta and evaluate antimicrobial and antibiofilm potential against selected bacterial and fungal isolates using standard microbiological protocols. Different techniques like FTIR spectroscopy, GC-MS, electron microscopy and HPLC were used to characterize the AgNPs. The AgNPs synthesized from crude extract of leaves and bulb were checked and were found effective against all the bacterial isolates except E. coli however, strong biofilm inhibition potential was observed in case of E.coli. The synthesized AgNPs showed dose dependent zone of inhibition higher for methanol and lower for n-Hexane against both Gram + ve and Gram -ve bacterial strains, exhibiting the anti-microbial potential. Biofilm inhibition was recorded at sub-MIC values against Gram + ve and Gram -ve bacterial strains. Antifungal activity of AgNPs was observed only at a higher concentration against Aspergillus niger, Fusarium oxysporum and Alternaria alternata while Aspergillus terreus was resistant even at higher concentrations. In conclusion, we can say that the plant possesses pronounced antimicrobial potential with a wide range of the bioactive compounds, which can be explored for pharmaceutical purposes.

Annona muricata silver nanoparticles exhibit strong anticancer activities against cervical and prostate adenocarcinomas through regulation of CASP9 and the CXCL1/CXCR2 genes axis

BACKGROUND

Green synthesized nanoparticles have been earmarked for use in nanomedicine including for the development of better anticancer drugs.

OBJECTIVE

The aim of this study was to undertake biochemical evaluation of anticancer activities of green synthesized silver nanoparticles (AgNPs) from ethanolic extracts of fruits (AgNPs-F) and leaves (AgNPs-L) of Annona muricata.

METHODS

Previously synthesized silver nanoparticles were used for the study. The effects of the AgNPs and 5-Fluorouracil were studied on PC3, HeLa and PNT1A cells. The resazurin, migration and colonogenic assays as well as qRT-PCR were employed.

RESULTS

The AgNPs-F displayed significant antiproliferative effects against HeLa cells with an IC50 of 38.58μg/ml and PC3 cells with an IC50 of 48.17μg/ml but selectively spared normal PNT1A cells (selectivity index of 7.8), in comparison with first line drug 5FU and AgNPs-L whose selectivity index were 3.56 and 2.26 respectively. The migration assay revealed potential inhibition of the metastatic activity of the cells by the AgNPs-F while the colonogenic assay indicated the permanent effect of the AgNPs-F on the cancer cells yet being reversible on the normal cells in contrast with 5FU and AgNPs-L. CASP9 was significantly over expressed in all HeLa cells treated with the AgNPs-F (1.53-fold), AgNPs-L (1.52-fold) and 5FU (4.30-fold). CXCL1 was under expressed in HeLa cells treated with AgNPs-F (0.69-fold) and AgNPs-L (0.58-fold) and over expressed in cells treated with 5FU (4.95-fold), but the difference was not statistically significant. CXCR2 was significantly over expressed in HeLa cells treated with 5FU (8.66-fold) and AgNPs-F (1.12-fold) but under expressed in cells treated with AgNPs-L (0.76-fold).

CONCLUSIONS

Here we show that biosynthesized AgNPs especially AgNPs-F can be used in the development of novel and better anticancer drugs. The mechanism of action of the AgNPs involves activation of the intrinsic apoptosis pathway through upregulation of CASP9 and concerted down regulation of the CXCL1/ CXCR2 gene axis.

Therapeutic Potential of Green Synthesized Metallic Nanoparticles against Staphylococcus aureus

BACKGROUND

The recent treatment challenges posed by the widespread emergence of pathogenic Multidrug-Resistant (MDR) bacterial strains are a cause of huge health troubles worldwide. Infections caused by MDR organisms are associated with longer period of hospitalization, increased mortality, and inflated healthcare costs. Staphylococcus aureus is one of these MDR organisms identified as an urgent threat to human health by the World Health Organization. Infections caused by S. aureus may range from simple cutaneous infestations to life threatening bacteremia. S. aureus infections get easily escalated in severely ill, hospitalized and or immunocompromised patients with incapacitated immune system. Also, in HIV-positive patients S. aureus ranks amongst one of the most common comorbidities where it can further worsen a patient's health condition. At present anti-staphylococcal therapy is reliant typically on chemotherapeutics that are gathering resistance and pose unfavorable side-effects. Thus, newer drugs are required that can bridge these shortcomings and aid effective control against S. aureus.

OBJECTIVE

In this review, we summarize drug resistance exhibited by S. aureus and lacunae in current anti-staphylococcal therapy, nanoparticles as an alternative therapeutic modality. The focus lays on various green synthesized nanoparticles, their mode of action and application as potent antibacterial compounds against S. aureus.

CONCLUSION

Use of nanoparticles as anti-bacterial drugs has gained momentum in recent past and green synthesized nanoparticles, which involves microorganisms and plants or their byproducts for synthesis of nanoparticles offer a potent, as well as environment friendly solution in warfare against MDR bacte.

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

Published studies indicate that virtually any kind of botanical material can be exploited to make biocompatible, safe, and cost-effective silver nanoparticles. This hypothesis is supported by the fact that plants possess active bio-ingredients that function as powerful reducing and coating agents for Ag+. In this respect, a phytomediation method provides favourable monodisperse, crystalline, and spherical particles that can be easily purified by ultra-centrifugation. However, the characteristics of the particles depend on the reaction conditions. Optimal reaction conditions observed in different experiments were 70-95 °C and pH 5.5-8.0. Green silver nanoparticles (AgNPs) have remarkable physical, chemical, optical, and biological properties. Research findings revealed the versatility of silver particles, ranging from exploitation in topical antimicrobial ointments to in vivo prosthetic/organ implants. Advances in research on biogenic silver nanoparticles have led to the development of sophisticated optical and electronic materials with improved efficiency in a compact configuration. So far, eco-toxicity of these nanoparticles is a big challenge, and no reliable method to improve the toxicity has been reported. Therefore, there is a need for reliable models to evaluate the effect of these nanoparticles on living organisms.

Photo-assisted bio-fabrication of silver nanoparticles using Annona muricata leaf extract: exploring the antioxidant, anti-diabetic, antimicrobial, and cytotoxic activities

Green synthesis of metal nanoparticles is reputed to have a robust range of biomedical applications. Silver nanoparticles (AgNPs) bio-fabricated using aqueous leaf extract of Annona muricata were characterized and evaluated for in-vitro antioxidant, lipid peroxidation inhibition, anti-diabetic and antimicrobial activities as well as cytotoxicity in human keratinocyte cells (HaCaT). The extract induced colour change of silver salt solution which absorbed at 420 nm and confirmed the formation of AgNPs. FTIR showed that free amide and hydroxyl groups were responsible for the synthesized nanoparticles. Both XRD and SAED confirmed the crystalline nature of the particles with face centered cubic (FCC) phase. The zeta potential revealed -27.2 mV potential and average distribution size of 35 nm. DLS indicated that the majority of the particles were 86.78 nm size and with a polydispersity index (PDI) of 0.329. AgNPs displayed strong activities against DPPH (IC₅₀ = 51.80 μg/ml), ABTS (IC₅₀ = 30.78 μg/ml), α-amylase (IC₅₀ = 0.90 μg/ml) and α-glucosidase (IC₅₀ = 3.32 μg/ml). The particles exhibited a dose-dependent inhibition of Fe²⁺-induced lipid peroxidation with effective antimicrobial activity against a battery of bacterial strains and cytotoxicity in HaCaT cell line. These findings revealed the potential biomedical applications of the particles and further work will be required to establish its molecular mechanism of action.