Determination of Antimicrobial and Toxic Metal Removal Activities of Plant-Based Synthesized (Capsicum annuum L. Leaves), Ecofriendly, Gold Nanomaterials

A comprehensive review on sustainable strategies for valorization of pepper waste and their potential application

Pepper is an economically important crop grown worldwide for consumption as a vegetable and spice. Much waste, including crop plant waste, seeds, stalks, placenta, peels, and other processing byproducts, is generated by consumers during pepper crop production, processing, retail, and households. These peppers byproducts contain numerous bioactive compounds that can be used as ingredients for developing functional foods, nutraceuticals, and other food industries. This review summarizes the recent developments in the valorization of pepper waste. The content of bioactive compounds in different pepper wastes, their extraction processes, biological activities, and applications are discussed and given special attention. Pepper waste and byproducts are rich sources of nutrients and bioactive compounds, such as vitamins, dietary fiber, capsaicinoids, phenolics, flavonoids, and carotenoids, which possess health-promoting effects, including antioxidant, antimicrobial, anti-inflammatory, antidiabetic, anti-obesity, and anticancer activities. Considering the potential for application of the bioactive compounds in food, nutraceuticals, and pharmaceutical industries, future studies are recommended to develop efficient and economical green extraction techniques and evaluate the sensorial characteristics, bioaccessibility, and safety of the bioactive compounds. Several strategies are also available for developing technologies to valorize pepper waste for possible applications other than in the food and biomedical industries. However, a sustainability check of the technologies and a joint effort by stakeholders at all levels is the key to reducing pepper waste and the sustainable valorization of the waste.

Green synthesis of gold nanoparticles via Moringa oleifera seed extract: antioxidant, antibacterial and anticarcinogenic activity on lung cancer

Plant-mediated biosynthesis of nanoparticles is a green method that allows synthesis in one-pot process. Synthesis of gold nanoparticles with plant extracts has gained interest in the field of biomedicine due to its variety of applications. This study presents the synthesis via green chemistry of gold nanoparticles (AuNPs) using the methanol extract of Moringa oleifera seeds. The AuNPs were synthesized at room temperature. UV-Vis spectroscopy confirmed the formation of AuNPs by identifying the surface plasmon resonance located at 546 nm. TEM analysis shows spherical nanoparticles. FTIR analysis demonstrated the presence of specific bioactive molecules responsible for the Au3+ ion reduction process. The antioxidant activity of the nanoparticles was evaluated on the stabilization of the DPPH radical (1,1-diphenyl-2-picrylhydrazyl, 2,2-diphenyl-1-(2,4,6-trinitrophenyl) hydrazyl). The antimicrobial activity analysis was developed by broth microdilution method at different concentrations against Escherichia coli and Staphylococcus aureus. Minimum inhibitory concentration were 400 µg/mL and 200 µg/mL, respectively. A549 lung cancer cell proliferation was measured according to the MTT protocol, indicating a dose-dependent response and a IC50 of 163.9 ± 13.27 µg/mL. The AuNPs synthesized using M. oleifera seeds showed promise as active materials for antimicrobial or anticancer products.

Biosynthesis, Characterization, and Biomedical Applications of Gold Nanoparticles with Cucurbita moschata Duchesne Ex Poiret Peel Aqueous Extracts

In this study, AuNPs were biosynthesized from Cucurbita moschata fruit peel extracts. Biosynthesized AuNPs exhibited maximum absorbance at a 555 nm wavelength, and XRD analysis indicated that the CM-AuNPs had a particle size of less than 100 nm and a cubic crystal structure. TEM scans revealed that the gold particles exhibited a spherical morphology, with an average size of 18.10 nm. FTIR analysis revealed strong peaks indicating the presence of functional groups involved in the reduction reactions. The surface charge of the biosynthesized AuNPs was determined to be -19.7 mV. The antibacterial and antifungal activities of AuNPs against pathogen strains were assessed by the minimum inhibitory concentration (MIC) method. The cytotoxic effects of CM-AuNPs on cancer cell lines (Sk-Ov-3, CaCo2, and A549) and healthy cell lines (HUVEC) were investigated using the MTT method. The findings indicated that AuNPs biosynthesized by the green synthesis method using C. moschata peel aqueous extract had high inhibition on the growth of pathogenic microorganisms and effective cytotoxic activity against cancerous cell lines at low doses. As a result, it can be concluded that CM-AuNPs will be eminently effective in the production of antibacterial and/or anticancer drugs in the pharmaceutical, food, and cosmetic industries.

A comprehensive review on antibacterial analysis of natural extract-based metal and metal oxide nanoparticles

Pharmaceutical, food packing, cosmetics, agriculture, energy storage devices widely utilize metal and metal oxide nanoparticles prepared via different physical and chemical methods. It resulted in the release of several dangerous compounds and solvents as the nanoparticles were being formed. Currently, Researchers interested in preparing nanoparticles (NPs) via biological approach due to their unique physiochemical properties which took part in reducing the environmental risks. However, a number of microbial species are causing dangerous illnesses and are a threat to the entire planet. The metal and metal oxide nanoparticles played a significant role in the identification and elimination of microbes when prepared using natural extract. Its biological performance is thus also becoming exponentially more apparent than it was using in conventional techniques. Despite the fact that they hurt germs, their small size and well-defined shape encourage surface contact with them. The generation of Reactive Oxygen Species (ROS), weakens the bacterial cell membrane by allowing internal cellular components to seep out. The bacterium dies as a result of this. Numerous studies on different nanoparticles and their antibacterial efficacy against various diseases are still accessible. The main objective of the biogenic research on the synthesis of key metals and metal oxides (such as gold, silver, titanium dioxide, nickel oxide, and zinc oxide) using various plant extracts is reviewed in this study along with the process of nanoparticle formation and the importance of phytochemicals found in the plant extract.

Green Synthesis of Silver Nanoparticles Derived from Papaver rhoeas L. Leaf Extract: Cytotoxic and Antimicrobial Properties

In the last few decades, the search for metal nanoparticles as an alternative to cancer treatments and antibiotics has increased. In this article, the spectroscopic (ultraviolet-visible (UV-vis), electron-dispersing X-ray (EDX), and Fourier transform infrared (FT-IR)), microscopic (field emission scanning electron microscope (FE-SEM), transmission electron microscope (TEM), and atomic force microscope (AFM)), structural (X-ray diffractometer (XRD) and zetasizer), and analytic (thermogravimetric/differential thermal analyzer (TGA-DTA)) characterization of the silver nanoparticles (AgNPs) produced from Papaver rhoeas (PR) L. leaf extract are presented. PR-AgNPs are generally spherical and have a maximum surface plasmon resonance of 464.03 nm. The dimensions of the manufactured nanomaterial are in the range of 1.47-7.31 nm. PR-AgNPs have high thermal stability and a zeta potential of -36.1 mV. The minimum inhibitory concentration (MIC) values (mg L-1) of PR-AgNPs on Staphylococcus aureus, Escherichia coli, Bacillus subtilis, Pseudomonas aeruginosa, and Candida albicans are 1.50, 0.75, 3.00, 6.00, and 0.37, respectively. In the study, the cytotoxic and proliferative effects of PR-AgNPs using the MTT (3-(4,5-dimethylthiazol-2-yl)-diphenyltetrazolium bromide) method on various cancer cell lines (CACO-2 (human colon adenocarcinoma cell), MCF-7 (human breast cancer cell), T98-G (glioblastoma multiforme cell), and healthy HUVEC (human umbilical vein endothelial cell)) cell lines are presented. After 24 and 48 h of the application, the half-maximum inhibitory concentration (IC50) values (μg mL-1) of PR-AgNPs on HUVEC, CACO-2, MCF-7, and T98-G lines are 2.365 and 2.380; 2.526 and 2.521; 3.274 and 3.318; 3.472 and 3.526, respectively. Comprehensive in vivo research of PR-AgNPs is proposed to reveal their potential for usage in sectors such as nanomedicine and nanochemistry.

Investigation of Antimicrobial and Cytotoxic Properties and Specification of Silver Nanoparticles (AgNPs) Derived From Cicer arietinum L. Green Leaf Extract

Using biological materials to synthesize metallic nanoparticles has become a frequently preferred method by researchers. This synthesis method is both fast and inexpensive. In this study, an aqueous extract obtained from chickpea (Cicer arietinum L.) (CA) leaves was used in order to synthesize silver nanoparticles (AgNPs). For specification of the synthesized AgNPs, UV-vis spectrophotometer, Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction analysis (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), electron dispersive X-ray (EDX), and zeta potential (ZP) analyses data were used. Biologically synthesized AgNPs demonstrated a maximum surface plasmon resonance of 417.47 nm after 3 h. With the powder XRD model, the mean crystallite dimension of nanoparticles was determined as 12.17 mm with a cubic structure. According to the TEM results, the dimensions of the obtained silver nanoparticles were found to be 6.11-9.66 nm. The ZP of the electric charge on the surface of AgNPs was measured as -19.6 mV. The inhibition effect of AgNPs on food pathogen strains and yeast was determined with the minimum inhibition concentration (MIC) method. AgNPs demonstrated highly effective inhibition at low concentrations especially against the growth of B. subtilis (0.0625) and S. aureus (0.125) strains. The cytotoxic effects of silver nanoparticles on cancerous cell lines (CaCo-2, U118, Sk-ov-3) and healthy cell lines (HDF) were revealed. Despite the increase of AgNPs used against cancerous and healthy cell lines, no significant decrease in the percentage of viability was detected.

Green Synthesis of Gold and Silver Nanoparticles Using Leaf Extract of Capsicum chinense Plant

So far, several studies have focused on the synthesis of metallic nanoparticles making use of extracts from the fruit of the plants from the genus Capsicum. However, as the fruit is the edible, and highly commercial, part of the plant, in this work we focused on the leaves, a part of the plant that is considered agro-industrial waste. The biological synthesis of gold (AuNPs) and silver (AgNPs) nanoparticles using aqueous extracts of root, stem and leaf of Capsicum chinense was evaluated, obtaining the best results with the leaf extract. Gold and silver nanoparticles synthesized using leaf extract (AuNPs-leaf and AgNPs-leaf, respectively) were characterized by UV-visible spectrophotometry (UV-Vis), Fourier Transform Infrared Spectroscopy with Attenuated Total Reflection (FTIR-ATR), X-ray Photoelectron Spectroscopy (XPS), Ultra Hight Resolution Scanning Electron Microscopy coupled to Energy-Dispersive X-ray spectroscopy (UHR-SEM-EDX) and Transmission Electron Microscopy (TEM), and tested for their antioxidant and antimicrobial activities. In addition, different metabolites involved in the synthesis of nanoparticles were analyzed. We found that by the use of extracts derived from the leaf, we could generate stable and easy to synthesize AuNPs and AgNPs. The AuNPs-leaf were synthesized using microwave radiation, while the AgNPs-leaf were synthesized using UV light radiation. The antioxidant activity of the extract, determined by ABTS, showed a decrease of 44.7% and 60.7% after the synthesis of the AuNPs-leaf and AgNPs-leaf, respectively. After the AgNPs-leaf synthesis, the concentration of polyphenols, reducing sugars and amino acids decreased by 15.4%, 38.7% and 46.8% in the leaf extract, respectively, while after the AuNPs-leaf synthesis only reducing sugars decreased by 67.7%. These results suggest that these groups of molecules are implicated in the reduction/stabilization of the nanoparticles. Although the contribution of these compounds in the synthesis of the AuNPs-leaf and the AgNPs-leaf was different. Finally, the AgNPs-leaf inhibited the growth of S. aureus, E. coli, S. marcescens and E. faecalis. All of them are bacterial strains of clinical importance due to their fast antibiotic resistance development.

Ecofriendly Synthesis of Silver Nanoparticles Using Ananas comosus Fruit Peels: Anticancer and Antimicrobial Activities

Metallic nanoparticles are valuable materials and have a range of uses. Nanoparticles synthesized from plant wastes by environment-friendly methods have attracted the attention of researchers in recent years. Also, the advantages of biological resources and synthesis methods are attracting attention. In this study, silver nanoparticles were synthesized from Ananas comosus fruit peels using ecofriendly method steps. The characterization of the particles obtained was determined by using a UV-visible spectrophotometer (UV-Vis.), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction diffractometer (XRD), Fourier scanning electron microscope (FESEM), and transmission electron microscopy (TEM). The nanoparticles showed maximum absorbance at 463 nm, measuring 11.61 in crystal nanosize, and presented spherical in appearance. An antimicrobial activity test was determined with the minimum inhibition concentration (MIC) method. The nanoparticles showed promising inhibitory activity on the Gram-positive and Gram-negative pathogen microorganisms (Escherichia coli ATCC25922, Staphylococcus aureus ATCC29213, Bacillus subtilis ATCC11774, Pseudomonas aeruginosa ATCC27833 bacteria, and Candida albicans yeast) at low concentrations. The cytotoxic and growth inhibitory effects of silver nanoparticles on different cancer cell lines were examined via the MTT assay.

Methods of green synthesis of Au NCs with emphasis on their morphology: A mini-review

Greener synthetic methods are becoming more popular as a means of reducing environmental pollution caused by reaction byproducts. Another important advantage of green methods is their low cost and the abundance of raw materials. Herein, we investigate the green Au nanoclusters (NCs) using microorganisms (bacteria and fungi) and plant extraction with various shapes and development routes. Natural products derived from plants, tea, coffee, banana, simple amino acids, enzyme, sugar, and glucose have been used as reductants and as capping agents during synthesis in literature. The synthesis techniques are generally chemical, physical and green methods. Green synthesis of Au NCs using bacteria and fungi can be divided into intracellular and extracellular. In an intracellular manner, bacterial cells are implanted in a culture medium containing salt and heated under suitable growth conditions. However, in an extracellular manner, the Au ions are directed from the outside into the cell. Thus, these methods are considered as a better alternative to chemical and physical synthesis. The research on green synthesis of Au nanoparticles (NPs) and its influence on their size and morphology are summarized in this review.