Nelumbo nucifera leaf extract mediated synthesis of silver nanoparticles and their antimicrobial properties against some human pathogens

An Updated Review on Nelumbo Nucifera Gaertn: Chemical Composition, Nutritional Value and Pharmacological Activities

Nelumbo nucifera Gaertn is a recognised herbal plant in ancient medical sciences. Each portion of the plant leaf, flower, seed and rhizome is utilised for nutritional and medicinal purposes. The chemical compositions like phenol, alkaloids, glycoside, terpenoids and steroids have been isolated. The plant contains various nutritional values like lipids, proteins, amino acids, minerals, carbohydrates, and fatty acids. Traditional medicine confirms that the phytochemicals of plants give significant benefits to the treatment of various diseases such as leukoderma, smallpox, dysentery, haematemesis, coughing, haemorrhage, metrorrhagia, haematuria, fever, hyperlipidaemia, cholera, hepatopathy and hyperdipsia. To verify the traditional claims, researchers have conducted scientific biological in vivo and in vitro screenings, which have exhibited that the plant keeps various notable pharmacological activities such as anticancer, hepatoprotective, antioxidant, antiviral, hypolipidemic, anti-obesity, antipyretic, hypoglycaemic, antifungal, anti-inflammatory and antibacterial activities. This review, summaries the nutritional composition, chemical constituents and biological activities substantiated by the researchers done in vivo and in vitro.

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.

Bambusa arundinacea leaves extract-derived Ag NPs: evaluation of the photocatalytic, antioxidant, antibacterial, and anticancer activities

Bio-fabrication has become a safe approach for silver nanoparticles (Ag NPs). The plant-mediated biosynthesized Ag NPs have emerged as a potential substitute for conventional chemical formation. The biosynthesized Ag NPs were analyzed in terms of crystalline nature, morphology, chemical composition, particle size, stability, size, and shape of the particles. The XRD, FTIR, and TEM analysis indicate the presence of the bioactive secondary metabolites compounds. The bamboo-mediated Ag NPs demonstrated a notable antibacterial efficacy against Gram-positive and Gram-negative pathogenic microorganisms and showed significant antioxidant activity against DPPH free radicals. The degradation of methylene blue at various intervals under solar light irradiation was used to evaluate the photocatalytic performance of Ag NPs. Further, Ag NPs conveyed potent anticancer activity against MCF-7 cell lines with a significant value IC₅₀. The bamboo leaves-mediated Ag NPs synthesized Ag NPs signified strong antibacterial, antioxidant, and anticancer activity; hence, it can be used in various biomedical applications and face mask coating to prevent the coronavirus after successful clinical trials in research laboratories.

In vitro cytotoxicity against breast cancer using biogenically synthesized gold and iron oxide nanoparticles derived from the hydroethanolic extract of Salvia officinalis L

Nanotechnology has a real-world impact on every aspect of life. Many researchers have been drawn to the biosynthesis of gold and iron oxide nanoparticles (Au-NPs and SPIONS) because they have a wide range of life applications. In this work, a single-step environmentally friendly biosynthesis of Au-NPs and SPIONS is reported by reducing solutions of gold aureate and ferric chloride is reported for the first time using the hydroethanolic extract (HEE) of Salvia officinalis (S. officinalis), an edible plant found in Egypt. The phytochemicals present in HEE were responsible for the reduction as well as stabilization of these nanoparticles. Before using the HEE, it was phytochemically screened for its constituents. Qualitatively, the HEE was found to have comparable levels of phenolics, flavonoids, tannins, proteins, carbohydrates, terpenoids, steroids, and polysaccharides. Quantitatively, total phenolics (236.91 ± 2.15 mg GAE/g extract), flavonoids (91.38 ± 0.97 mg QE/g extract), tannins (101.60 ± 1.33 mg/g extract), proteins (284.62 ± 2.65 mg/g extract), carbohydrates (127.73 ± 1.68 mg/g extract), soluble sugars (52.3 ± 0.67 mg/g extract), and polysaccharides (75.43 ± 1.01 mg/g extract) were estimated. In addition, HPLC analysis revealed the identification of seven phenolic compounds [ferulic (67.26%), chlorogenic (3.12%), caffeic (3.11%), p-coumaric (1.13%), protocatechuic (0.65%), catechin (0.69%), rosmarinic (0.53%)] and three flavonoids [apigenin (5.29%), quercetin-7-O-glucoside (3.39%), and luteolin-7-O-rutinose (2.01%)]. The characterization of the biosynthesized NPs was confirmed by Fourier transform infrared (FT-IR) spectroscopy, UV–Vis absorption spectroscopy, X-ray diffraction (XRD), and transmission electron microscopy (TEM). In vitro cytotoxic studies showed that Au-NPs, SPIONS, and HEE have an inhibitory effect on the growth of human breast cancer (MCF-7) cells at an IC50 of 6.53, 6.97, and 26.12 µg mL−1, respectively, by comparison with the standard drug (Doxorubicin) effect (0.18 µg mL−1).

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

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

Green Fabrication of Bioactive Silver Nanoparticles Using Mentha pulegium Extract under Alkaline: An Enhanced Anticancer Activity

Fabrication of silver nanoparticles (AgNPs) using Chinese herbal medicine is popular as the bioactive components included in them would generate potential synergistic effect with the metal nanoparticles. The leaf of Mentha pulegium, whose extract contains a range of phytochemicals and exhibits a wide spectrum of bioactivities, is used as Chinese herbal medicine after drying naturally. Thus, the green synthesis of AgNPs using Mentha pulegium has aroused interests from analysts. However, the biosynthesis of AgNPs under alkaline conditions and the biological activities remain elusive, where alkaline conditions may influence the physicochemical properties and the biological activities of biosynthesized AgNPs. In this study, we were stimulated to fabricate bioactive AgNPs using Mentha pulegium extract under alkaline conditions, accompanied by a systematic evaluation on the effect of biosynthesis parameters on the formation, average size, and polydispersity of AgNPs. Our results showed that alkaline conditions could accelerate the formation of AgNPs with a small average size but at a disadvantage to the polydispersity. Additionally, the as-prepared AgNPs had a hexagonal structure and spherical shape with an average size of 15.7 ± 0.1 nm, existing in the monodispersed form and revealing a high degree of stability. The AgNPs exhibited potent antioxidant and significant inhibitory activity for both bacterial and cancer cell lines. The MIC values of AgNPs for Staphylococcus aureus and Escherichia coli were both 50.0 μg·mL-1, and the IC50 values for HCT116, HepG2, and HeLa cells were 9.0, 14.5, and 31.5 μg·mL-1, respectively. The AgNPs biosynthesized using M. pulegium under alkaline conditions, which had a smaller size and more surface loads, are entirely different with those synthesized under acidic conditions, and the anticancer activity increased significantly. The internalization of AgNPs inside these five cells displayed a variant trend with variable AgNPs concentrations, suggesting the different mechanism of cell death. For two pathogens, HCT116 and HepG2 cancer cell lines, both cell wall and intracellular damage may be responsible for the cell death. However, for Hela cell line the cell death may be rooted in oxidative stress or intracellular penetration. These results confirmed that the AgNPs biosynthesized from M. pulegium extract under alkaline conditions would act as better anticancer agents in biomedicine.

A novel green synthesis of silver nanoparticles by the residues of Chinese herbal medicine and their biological activities

Green synthesis of silver nanoparticles (AgNPs) by using the extracts of Chinese herbal medicines (CHMs) has attracted tremendous attention due to the potential synergistic effect between metal nanoparticles and capping agents. However, since CHMs are precious and expensive, finding other cheap and eco-friendly resources for biosynthesizing AgNPs with superior medicinal activites is necessary. Herbal medicine residues (HMRs) are the by-products of traditional Chinese herbal medicine after decoction and were identified to contain approximately 30-50% of medicinally active ingredients, which may be advantageous for green synthesis of medicinal AgNPs. Inspired by this, we present herein the preparation of AgNPs by reusing Bazheng Mixture residues and evaluate both biosynthesis parameters and bioactivities, where Bazheng Mixture is a famous Chinese patent medicine for relieving inflammation and pain, and allaying fever. The UV-visible spectrum and DLS analysis showed that the as-prepared AgNPs were sensitive to pH, material proportion and incubation time, but the yield was impervious to material proportion. TEM, HRTEM, SAED and DLS characterization found that AgNPs (pH 10.0; material proportion 1 : 1; 6 h) had a face-centered cubic (fcc) structure and spherical shape with an average size of 22.2 ± 0.5 nm covered by anions, and existed in monodispersed form with long term stability. The AgNPs displayed potent toxic effects against both cancer cell lines and pathogens, and superior antioxidant activity. The IC50 for HCT116, HepG2 and HeLa cell lines were 13.07, 19.67, and 26.18 μg mL-1, respectively. The MICs of AgNPs for E. coli and S. aureus were both 50.0 μg mL-1. The uptake analysis of AgNPs for both pathogens and cancer cell lines was performed to preliminarily illustrate the mechanism of toxic effects. These results confirm that HMRs could be a low-cost, nontoxic and eco-friendly resource for green synthesis of medicinal AgNPs, and also provide an alternative method for general recycling strategies of HMRs.

Evaluation of biosynthesis parameters, stability and biological activities of silver nanoparticles synthesized by Cornus Officinalis extract under 365 nm UV radiation

Since silver nanoparticles (AgNPs) synthesized by using plant extracts revealed varied biological activities, the green synthesis of AgNPs has attracted considerable attention. Although the green synthesis of AgNPs have been accomplished by using the extracts of Cornus Officinalis, which is a traditional Chinese medicine and exhibits a wide spectrum of phytochemicals. The effects of biosynthesis parameters on reducing reaction, stability and more broad biological activities of so-prepared AgNPs did not been evaluated. In this paper, we firstly assessed the effects of UV radiation, pH, material proportion and radiation times on the green synthesis of AgNPs under 365 nm UV radiation by UV-visible spectrum and dynamic light scattering (DLS) analysis. The results showed that UV radiation could accelerate the formation of AgNPs and influence the average size below pH 7.0, and the size of so-prepared AgNPs were sensitive to the pH and material proportion, but no obvious changes to UV radiation times, offering a size-controlled synthetic method for AgNPs. The further X-ray diffraction (XRD), transmission electron microscopy (TEM) and DLS studies showed AgNPs synthesized at pH 7.0, extract: AgNO₃ = 1 : 1 and after 4 h UV radiation were a face-centered cubic (fcc) structure and both spherical and polygonal in shape with average particle size of 64.5 ± 0.3 nm existed in a monodispersed form. Subsquently, the stability of AgNPs was analyzed by zeta potential (-24.8 mV) and the average size measurement after 30 days storage (63.3 ± 0.4 nm), revealing a high degree of stability. Lastly, the investigation of biological activities showed that the biosynthesized AgNPs had potent antioxidant activity, antimicrobial activity against both S. aureus and E. coli as well as anticancer activity against HCT116 and HepG2 cell lines but negligible cytotoxicity against SW620. And the internalization of biosynthesized AgNPs inside the bacterial cell was evaluated by flow cytometric analysis, where the SSC values have significant increase after treating with nanoparticles. These results confirmed that the biosynthesis parameters on the green synthesis of AgNPs by using Cornus Officinalis extract also played pivotal roles and so-prepared AgNPs would be useful for the development of new alternative antioxidant, antimicrobial and anticancer agents in biomedicine.

A size-controlled green synthesis of silver nanoparticles by using the berry extract of Sea Buckthorn and their biological activities

Herein, by using the Sea Buckthorn berry extract, we present a new eco-friendly approach for green synthesis of AgNPs, which reveal superior antioxidation and anticancer but poor antimicrobial activities.

Removal of toxic contaminants from water by sustainable green synthesised non-toxic silver nanoparticles

The study describes the synthesis of silver nanoparticles using 21 different plant extracts having medicinal properties. Molecular ultraviolet-visible spectroscopy shows that the λ_max of nanoparticles synthesised by different plant extracts varied and ranged between 400 and 468 nm. The ultraviolet results revealed that although synthesis of nanoparticles occurred by all plant extracts successfully, their size varies, this was further confirmed by differential light scattering. The synthesised nanoparticles were investigated for their antimicrobial properties. The most promising silver nanoparticles Ocimum sanctum and Artemisia annua assisted were further characterised using transmission electron microscopy and energy dispersive X-ray spectroscopy (EDX). EDX data confirms that synthesised nanoparticles are highly pure. Further these two plant assisted nanoparticles were studied for chemocatalytic and adsorptive properties. The silver nanoparticles from Ocimum sanctum can catalyse the reduction of 4-nitrophenol (63%) within 20 min in the presence of NaBH₄, whereas Artemisia annua assisted silver nanoparticles did not show significant chemocatalytic activity. Both the promising nanoparticles can efficiently adsorb textile dyes from aqueous solutions. These synthesised nanoparticles were also exploited to remove microbial and other contaminants from Yamuna River water. The nanoparticles show excellent antimicrobial properties and can be reused repeatedly.