Ionic liquid based extraction of flavonoids from Elaeis guineensis leaves and their applications for gold nanoparticles synthesis

A review on green approaches utilizing phytochemicals in the synthesis of vanadium nano particles and their applications

In the modern era, inorganic nanoparticles have received profound attention as they possess boundless applications in various fields. Among these, vanadium-based nanoparticles (VNPs) are highly remarkable due to their inherent physiological and biological properties with many therapeutic and other applications, such as drug delivery systems for diseases like cancer, environmental remediation, energy storage, energy conversion, and photocatalysis. Moreover, physically, and chemically synthesized VNPs are very versatile, however, these synthesis routes cause concern to health and the environment due to the highly savage reaction conditions, using highly toxic and harsh chemicals, which compel the researchers to develop an eco-friendly, greener, and sustainable route for synthesis. In this outlook, to avoid the innumerable limitations, a bio approach is used over chemical and physical methods. This present review emphasis on the role of various biological components in the synthesis, especially Phyto-molecules that acts as capping and reducing agent, and solvent system for the nanoparticles synthesis. Furthermore, the influence of various factors on the biogenic synthesized nanoparticles has also been discussed. Finally, potential applications of as-synthesized VNPs, principally as an antimicrobial agent and their role as a nanomedicine, energy applications as a supercapacitor, and photocatalytic agents, have been discussed.

Radix Pueraria Flavonoids Assisted Green Synthesis of Reduced Gold Nanoparticles: Application for Electrochemical Nonenzymatic Detection of Cholesterol in Food Samples

Using radix pueraria flavonoids (RPFs) as a reducing and stabilizing agent, we report a simple, cost-effective, and ecologically friendly green synthesis technique for gold nanoparticles (AuNPs) in the present study. Ultraviolet-visible (UV) spectroscopy, transmission electron microscopy (TEM), Fourier transform infrared (FTIR), and X-ray diffraction (XRD) investigations were used to characterize the AuNPs. The results demonstrated that the produced AuNPs were nearly spherical and that their particle sizes had a mean diameter of 4.85 ± 0.75 nm. The "Green" AuNPs, exhibiting remarkable peroxidase-like activity and Michaelis-Menten kinetics with high affinity for H2O2 and 3,3',5,5'-tetramethylbenzidine (TMB), were effectively applied to the fabrication of a sensitive nonenzymatic enhanced electrochemical sensor for the detection of cholesterol (Cho). Under optimum circumstances, it was possible to establish two linear ranges of 1-100 and 250-5000 μmol/L with a detection limit of 0.259 μmol/L (signal/noise ratio (S/N) = 3). The suggested sensor was utilized with satisfactory findings to determine the amount of Cho in food samples.

Microbe-mediated sustainable bio-recovery of gold from low-grade precious solid waste: A microbiological overview

In an era of electronics, recovering the precious metal such as gold from ever increasing piles of electronic-wastes and metal-ion infested soil has become one of the prime concerns for researchers worldwide. Biological mining is an attractive, economical and non-hazardous to recover gold from the low-grade auriferous ore containing waste or soil. This review represents the recent major biological gold retrieval methods used to bio-mine gold. The biomining methods discussed in this review include, bioleaching, bio-oxidation, bio-precipitation, bio-flotation, bio-flocculation, bio-sorption, bio-reduction, bio-electrometallurgical technologies and bioaccumulation. The mechanism of gold biorecovery by microbes is explained in detail to explore its intracellular mechanistic, which help it withstand high concentrations of gold without causing any fatal consequences. Major challenges and future opportunities associated with each method and how they will dictate the fate of gold bio-metallurgy from metal wastes or metal infested soil bioremediation in the coming future are also discussed. With the help of concurrent advancements in high-throughput technologies, the gold bio-exploratory methods will speed up our ways to ensure maximum gold retrieval out of such low-grade ores containing sources, while keeping the gold mining clean and more sustainable.

Green synthesis of copper nanoparticle using ionic liquid-based extraction from Polygonum minus and their applications

The present work reports the extraction of phenolic compounds from Polygonum minus using ionic liquid as extracting solvent. In this work, 1-Butyl-3-methylimidazolium hydrogen sulfate [BMIM][HSO₄] was used for the extraction of bioactive compounds. Accordingly, ionic liquids based microwave-assisted extraction treatment for separating of bioactive compounds from polygonum minus was first performed in the present study. The results obtained in this work have high extraction yield in comparison with conventional solvent. UV/Vis results showed that microwave synthesis was fast, well dispersed and nanosized copper nanoparticle (CuNPs) in comparison with conventional synthesis. CuNPs was characterised by X-Rays diffractometer (XRD), Fourier transform infrared (FTIR), dynamic light scattering (DLS), field emission scanning electron microscopy combined with energy dispersive x-rays (FESEM-EDX), and thermogravimetric analysis (TGA). All the instrumental analyses confirmed the particles were nanosized. Furthermore, the antibacterial activity of as-synthesised CuNPs showed effective inhibitory zone against three different bacteria. The photocatalytic degradation of copper nanoparticles was studied using methylene blue (MB) and methyl orange (MO) dyes under UV light and degraded 99.9% within short time 8 and 7 min.

Ionic Liquid Solutions as a Green Tool for the Extraction and Isolation of Natural Products

In the past few years, the application of ionic liquids (ILs) had attracted more attention of the researchers. Many studies focused on extracting active components from traditional herbals using ILs as alternative solvents so as to address the issue caused by the traditional methods for extraction of natural products (NPs) with organic chemical reagents. Through the summary of reported research work, an overview was presented for the application of ILs or IL-based materials in the extraction of NPs, including flavonoids, alkaloids, terpenoids, phenylpropanoids and so on. Here, we mainly describe the application of ILs to rich the extraction of critical bioactive constituents that were reported possessing multiple therapeutic effects or pharmacological activities, from medicinal plants. This review could shed some light on the wide use of ILs in the field of natural products chemistry to further reduce the environmental damage caused by large quantity of organic chemical reagents.