Biogenic synthesis and spectroscopic characterization of silver nanoparticles using leaf extract of Indoneesiella echioides: in vitro assessment on antioxidant, antimicrobial and cytotoxicity potential

Review green synthesis of silver nanoparticles by using plant extracts and their antimicrobial activity

Interest in the biosynthesis of nanoparticles has increased in the last era by researchers. Nanoparticles have several applications in different fields like optoelectronics, magnetic devices, drug delivery, and sensors. Nanoparticle synthesis by green methods is safe for the environment and should be explored and encouraged popularly since various plants' have the high extent to form these nanoparticles. Worldwide, UV spectroscopy, X-ray diffraction, Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), Dynamic Light Scattering (DLS), Atomic Force Microscopy (AFM) besides Fourier Transform Infrared Spectroscopy (FTIR) are used in many ways for characterize nanoparticles. The most advantageous use of AgNPs is their great attribution to be used as antimicrobial agents. Finally, concept of AgNPs synthesis is deserved to be the modern technical and medical concern. The current review shows a complete comprehensive and analytical survey of the biosynthesis of AgNPs with a particular focus on their activities as antimicrobials and the possible theories of their effect on the microbial cell and all influenced secondary metabolites.

Managing Apoptosis in Lung Diseases using Nano-assisted Drug Delivery System

Several factors exist that limit the efficacy of lung cancer treatment. These may be tumor-specific delivery of therapeutics, airway geometry, humidity, clearance mechanisms, presence of lung diseases, and therapy against tumor cell resistance. Advancements in drug delivery using nanotechnology based multifunctional nanocarriers, have emerged as a viable method for treating lung cancer with more efficacy and fewer adverse effects. This review does a thorough and critical examination of effective nano-enabled approaches for lung cancer treatment, such as nano-assisted drug delivery systems. In addition, to therapeutic effectiveness, researchers have been working to determine several strategies to produce nanotherapeutics by adjusting the size, drug loading, transport, and retention. Personalized lung tumor therapies using sophisticated nano modalities have the potential to provide great therapeutic advantages based on individual unique genetic markers and disease profiles. Overall, this review provides comprehensive information on newer nanotechnological prospects for improving the management of apoptosis in lung cancer.

Plant Extract-Based Synthesis of Metallic Nanomaterials, Their Applications, and Safety Concerns

Nanotechnology has attracted the attention of researchers from different scientific fields because of the escalated properties of nanomaterials compared with the properties of macromolecules. Nanomaterials can be prepared through different approaches involving physical and chemical methods. The development of nanomaterials through plant-based green chemistry approaches is more advantageous than other methods from the perspectives of environmental safety, animal, and human health. The biomolecules and metabolites of plants act as reducing and capping agents for the synthesis of metallic green nanomaterials. Plant-based synthesis is a preferred approach as it is not only cost-effective, easy, safe, clean, and eco-friendly but also provides pure nanomaterials in high yield. Since nanomaterials have antimicrobial and antioxidant potential, green nanomaterials synthesized from plants can be used for a variety of biomedical and environmental remediation applications. Past studies have focused mainly on the overall biogenic synthesis of individual or combinations of metallic nanomaterials and their oxides from different biological sources, including microorganisms and biomolecules. Moreover, from the viewpoint of biomedical applications, the literature is mainly focusing on synthetic nanomaterials. Herein, we discuss the extraction of green molecules and recent developments in the synthesis of different plant-based metallic nanomaterials, including silver, gold, platinum, palladium, copper, zinc, iron, and carbon. Apart from the biomedical applications of metallic nanomaterials, including antimicrobial, anticancer, diagnostic, drug delivery, tissue engineering, and regenerative medicine applications, their environmental remediation potential is also discussed. Furthermore, safety concerns and safety regulations pertaining to green nanomaterials are also discussed. This article is protected by copyright. All rights reserved.

Preservative potential of biosynthesized silver nanoparticles: prevention of xylem occlusion and microbial proliferation at postharvest stage of preservation

The purpose of the current study was to determine the appropriate genotype and concentration of biosynthesized silver nanoparticles effectual in preserving mulberry leaves at the postharvest stage. The preservative effect of silver nanoparticles was determined by their potentiality to prevent xylem blockage, chlorophyll content retention and inhibition of microbial proliferation within a preservative solution. For synthesizing silver nanoparticles, a blend of 10-3 M silver nitrate and S1 genotype of the mulberry leaf was found to be most effective. Silver nanoparticles at 6 ppm were observed to be the least effective concentration for preserving mulberry leaves for at least 7 days at the postharvest stage, as evident from physical texture and retention of chlorophyll content. Biosynthesized silver nanoparticles showed negative microbial count during the course of preservation as evident from no colony-forming unit (CFU) until the last day of preservation, while conventional preservative silver nitrate showed traces of CFU on a nutrient agar plate. Besides, these leaves preserved in nanosilver solution showed an almost negligible number of xylem blockage in the petiole, almost equivalent to the blockage nature of fresh leaves caused by the deposition of macromolecules like protein, lignin and suberin. Nanosilver- and silver nitrate-preserved leaves also displayed insignificant accumulation of reactive oxygen species (ROS) and greater retention of membrane integrity than leaves preserved in normal distilled water. Nanosilver solution showed greater durability of preserving mulberry leaves than conventional floral preservative silver nitrate, useful for feeding silkworm larvae during the rainy season.

Green synthesis of silver nanoparticles using plant extracts and their antimicrobial activities: a review of recent literature

Synthesis of metal nanoparticles using plant extracts is one of the most simple, convenient, economical, and environmentally friendly methods that mitigate the involvement of toxic chemicals. Hence, in recent years, several eco-friendly processes for the rapid synthesis of silver nanoparticles have been reported using aqueous extracts of plant parts such as the leaf, bark, roots, etc. This review summarizes and elaborates the new findings in this research domain of the green synthesis of silver nanoparticles (AgNPs) using different plant extracts and their potential applications as antimicrobial agents covering the literature since 2015. While highlighting the recently used different plants for the synthesis of highly efficient antimicrobial green AgNPs, we aim to provide a systematic in-depth discussion on the possible influence of the phytochemicals and their concentrations in the plants extracts, extraction solvent, and extraction temperature, as well as reaction temperature, pH, reaction time, and concentration of precursor on the size, shape and stability of the produced AgNPs. Exhaustive details of the plausible mechanism of the interaction of AgNPs with the cell wall of microbes, leading to cell death, and high antimicrobial activities have also been elaborated. The shape and size-dependent antimicrobial activities of the biogenic AgNPs and the enhanced antimicrobial activities by synergetic interaction of AgNPs with known commercial antibiotic drugs have also been comprehensively detailed.

Phytosynthesized nanoparticles as a potential cancer therapeutic agent

Plants are the well-known sources for the hyper-accumulation and reduction of metallic ions. Analysis of various plant extracts has justified the presence of different types of phytochemicals that possess the stabilization and reduction functionalities of precursors to form nanoparticles. Such characteristics make plants as an attractive source for synthesizing eco-friendly nanoparticles (NPs) with potentially less toxicity to the body. Recently, phytosynthesized nanoparticles have been explored for targeted inhibition and diagnosis of cancer cells without affecting non-cancerous healthy cells. The aim of this review is to discuss the characteristic performance of NPs synthesized from various plant sources for the diagnosis and inhibition of cancer. The mode of action of phytosynthesized nanoparticles for anti-cancer applications are also discussed.

Biosynthesis of Silver Nanoparticles Using Onion Endophytic Bacterium and Its Antifungal Activity against Rice Pathogen Magnaporthe oryzae

Biosynthesis of silver nanoparticles (AgNPs) using endophytic bacteria is a safe alternative to the traditional chemical method. The purpose of this research is to biosynthesize AgNPs using endophytic bacterium Bacillus endophyticus strain H3 isolated from onion. The biosynthesized AgNPs with sizes from 4.17 to 26.9 nm were confirmed and characterized by various physicochemical techniques such as Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), UV-visible spectroscopy, transmission electron microscopy (TEM) and scanning electron microscopy (SEM) in addition to an energy dispersive spectrum (EDS) profile. The biosynthesized AgNPs at a concentration of 40 μg/mL had a strong antifungal activity against rice blast pathogen Magnaporthe oryzae with an inhibition rate of 88% in mycelial diameter. Moreover, the biosynthesized AgNPs significantly inhibited spore germination and appressorium formation of M. oryzae. Additionally, microscopic observation showed that mycelia morphology was swollen and abnormal when dealing with AgNPs. Overall, the current study revealed that AgNPs could protect rice plants against fungal infections.

Antimicrobial activity of silver nanoparticles synthesised by using microbial biosurfactant produced by a newly isolated Bacillus vallismortis MDU6 strain

Microbial biosurfactants has evolved as green molecules and their chemical diversity has gained momentum in recent time not only in the field of environmental and industrial sectors but also in the pharmaceutical sector. In this study, an effort was made for the biosynthesis of silver nanoparticle (AgNPs) having antimicrobial and non-cytotoxic activities with the help of microbial biosurfactant extracted from a novel Bacillus vallismortis strain MDU6 (Genbank accession no. MH382951) from petroleum oil logged soil sample in Dibrugarh, Assam. The isolate shows excellent potential for the production of biosurfactant by reducing the surface tension of diesel supplemented medium up to 56.57% only within 5 days. FTIR spectra of the crude biosurfactant show the presence of ʋ_CH2 (asymmetric stretching), ʋ_CH2 (symmetric stretching), ʋ_C=C (stretch), ʋ_C-C (stretch), ʋ_C-H (bending), ʋ_C-O (stretch) and ʋ_C-H (bending) functional groups and LC-MS/MS analysis confirms it as a cyclic lipopeptide which is a mixture of surfactin and iturin. The synthesized AgNPs showed excellent antimicrobial activities against Escherichia coli (ATCC no. 25922), Listeria monocytogenes (ATCC No. BAA-751), Staphylococcus aureus (ATCC No. 9542) and Bacillus subtilis (ATCC no. 6051) and showed no cytotoxicity against primary mouse liver cell lines.

Green synthesized silver nanoparticles induced cytogenotoxic and genotoxic changes in Allium cepa L. varies with nanoparticles doses and duration of exposure

This study aimed to test the ability of aqueous leaf extract of Eichhornia crassipes (Mart.) Solms-Laubach to synthesize silver nanoparticles (AgNPs) and to estimate the cytotoxicity and genotoxicity of AgNPs using Allium cepa assay. Fresh Eichhornia crassipes plants were collected from the Nile River of Egypt. The mixed-shaped structures of the biogenic AgNPs were qualitatively characterized by UV-vis spectroscopy, scanning electron microscopy and transmission electron microscopy. Selected area electron diffraction confirmed the crystalline structure of AgNPs and energy dispersive X-ray analysis clarified the presence of the elemental silver in a percentage of 83.29%. The biogenic AgNPs were quite stable (0.316) and negatively charged (-18.5 mV) based on the polydispersity index values. Allium cepa L. roots were exposed to several AgNPs concentrations (0, 5, 10, 20, 40 and 80 mg L^-1) for different time intervals 2, 4 and 6 h. Cytotoxicity measured by both the spectrophotometric and macroscopic techniques recorded the maximum cell death of root tips of A. cepa after 20 mg L^-1 treatment. The analysis of comet assay output images showed an alteration of DNA repair kinetics. The use of aqueous leaf extract of E. crassipes (Mart.) Solms-Laubach in the large-scale production of AgNPs by the method proposed in this study may be a step in improving the water loss in the Nile River. At the same time, a sensitive approach to the cytogenotoxicity of AgNPs must be considered.

Batch process biosynthesis of silver nanoparticles using Equisetum arvense leaf extract

The plant extract of Equisetum arvense is applied to reduce silver ions to silver nanoparticles (AgNPs) in the batch method. When mixed with silver nitrate (AgNO3), the extract changed color from yellow to dark brown, and AgNPs were synthesized in 24 h. Plant extracts applied to synthetize metal NPs, provide a simple and eco-friendly approach and the biomolecules are used as reducing and capping agents. The nanoparticles were characterized by transmission electron microscopy (TEM), scanning electron microscopy, ultraviolet spectroscopy and X-ray diffraction (XRD) analyses. The dark brown solution showed a surface plasmon resonance of AgNPs around 448 nm. The XRD pattern showed the crystalline nature and high purity of AgNPs. Fourier transform infrared spectroscopy was employed to measure particular functional groups that reduce silver nitrate as AgNPs are formed. TEM revealed that the size of AgNPs was around 18–20 nm. Antibacterial activity assays with Escherichia coli and Staphylococcus aureus demonstrated that AgNPs reduced bacterial growth and produced well-defined inhibition zones.

Induction of intrinsic apoptotic signaling pathway in A549 lung cancer cells using silver nanoparticles from Gossypium hirsutum and evaluation of in vivo toxicity

In the past decade, the research communities raised wide concerns on using medicinal plants for synthesis of nanomaterials due to its effective biological activity, lower side effects and also eco-friendly manner. Our previous report concentrated on the biomedical efficacy of fine characterized silver nanoparticles (AgNPs) from Gossypium hirsutum (cotton) leaf extract. Further, the current examination is planned to reveal the molecular mechanisms involving for activation of mitochondria-mediated signaling pathway by AgNPs in human lung cancer cells (A549) using various biological endpoints such as apoptotic induction by HOECHST 33342, AO/EtBr and Rhodamine 123 staining, cell cycle analysis using flow cytometry, gene and protein expressions by RT-PCR and immunoblotting respectively. This study was further extended to identify the toxicity of AgNPs using an animal model. Interestingly, we observed that A549 cells treated with AgNPs resulted in G2/M arrest and ultimately leads to induction of apoptosis cell death. Moreover, gene analysis demonstrated that diminished expression of anti-apoptotic (Bcl-2) and enhanced expression of pro-apoptotic (Bax) mitochondrial genes. The alterations in the gene pattern may interrupt of mitochondrial membrane potential which facilitates the releasing of cytochrome c (cyt c) into cytosol. The cyt c act as a key molecule for activation of caspases (9 and 3) to initiate intrinsic apoptotic signaling cell death process. The histological analysis proven the application of AgNPs in nanomedicine is quietly harmless and would not cause any discernible stress like swelling and inflammation to the organs of mice. Taken together, this investigation may provide solid evidence for cotton crop mediated AgNPs induced apoptosis cell death pathway and offer a novel approach for cancer therapy.

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

In the field of medicine, nanomaterials, especially those derived using the green method, offer promise as anti-cancer agents and drug carriers. However, the biosafety of metallic nanoparticles used as anti-cancer agents remains a concern. The goal of this systematic review was to compare the cytotoxicity of different plant-mediated syntheses of metallic nanoparticles based on their potency, therapeutic index, and cancer cell type susceptibility in the hopes of identifying the most promising anti-cancer agents. A literature search of electronic databases including Science Direct, PubMed, Springer Link, Google Scholar, and ResearchGate, was conducted to obtain research articles. Keywords such as biosynthesis, plant synthesis, plant-mediated, metallic nanoparticle, cytotoxicity, and anticancer were used in the literature search. All types of research materials that met the inclusion criteria were included in the study regardless of whether the results were positive, negative, or null. The therapeutic index was used as a safety measure for the studied compound of interest. Data from 76 selected articles were extracted and synthesised. Seventy-two studies reported that the cytotoxicity of plant-mediated synthesis of metallic nanoparticles was time and/or dose-dependent. Biosynthesised silver nanoparticles demonstrated higher cytotoxicity potency compared to gold nanoparticles synthesised by the same plants (Plumbago zeylanica, Commelina nudiflora, and Cassia auriculata) irrespective of the cancer cell type tested. This review also identified a correlation between the nanoparticle size and morphology with the potency of cytotoxicity. Cytotoxicity was found to be inversely proportional to nanoparticle size. The plant-mediated syntheses of metallic nanoparticles were predominantly spherical or quasi-spherical, with the median lethal dose of 1⁻20 µg/mL. Nanoparticles with other shapes (triangular, hexagonal, and rods) were less potent. Metallic nanoparticles synthesised by Abutilon inducum, Butea monosperma, Gossypium hirsutum, Indoneesiella echioides, and Melia azedarach were acceptably safe as anti-cancer agents, as they had a therapeutic index of >2.0 when tested on both cancer cells and normal human cells. Most plant-mediated syntheses of metallic nanoparticles were found to be cytotoxic, although some were non-cytotoxic. The results from this study suggest a focus on a selected list of potential anti-cancer agents for further investigations of their pharmacodynamic/toxicodynamic and pharmacokinetic/toxicokinetic actions with the goal of reducing the Global Burden of Diseases and the second leading cause of mortality.