Green chemistry approaches for the synthesis of metallic nanoparticles have become a new and promising field of research in recent years. Synthesis of metal nanoparticles [like gold (Au), silver (Ag), lead (Pb), platinum (Pt), copper (Cu), iron (Fe), cadmium (Cd), and other metal oxides such as titanium oxide (TiO), zinc oxide (ZnO), etc.] by various chemical and physical approaches as well as the biological approaches mediated by number of microorganisms have been actively found. Plant-mediated synthesis approaches are found to be more reliable and economic route to synthesize these metal nanoparticles. Owing to the biodiversity of plant biomasses, the actual mechanism by which the plant constituents have contributed to the synthetic process is yet to be fully known. Although the feasibility of controlling, the size and shape of nanoparticles by variation in reaction conditions have been demonstrated in many studies. Conventionally, nanoparticles are synthesized by chemicals and physicochemical methods using several chemicals which later on become accountable for various risk due to their general toxicity, so that solving the objective biological approaches is coming up to fill these gaps. The plant-mediated synthesis process undergoes highly controlled approaches for making them suitable for metal nanoparticle synthesis. In addition, biological synthesis of metallic nanoparticles is inexpensive, one-step, and eco-friendly method. In addition, the plant-mediated nanoparticles are used as potential pharmaceutical agents for various diseases such as malaria, HIV, cancer, hepatitis, and other diseases. Including this some other relevant information regarding nanopharmaceutical products, companies that are involve in the manufacturing and commercialization process and their clinical trial status are also discussed. This review article gives an overview of the plant-mediated synthesis of metal nanoparticles, possible compounds, and mechanisms that might be responsible for the reduction process as well as the potential pharmacological applications, currently available nanopharmaceutical products and their marketing status.

Nanotechnology mainly involves the fabrication, manipulation, and utilization of materials in nano size (materials having size less than a micron to that of individual atoms). However, nanoparticles can be synthesized by several chemical and physical approaches; now, it is also possible to integrate the use of biological entities. In recent years, mycogenesis of nanoparticles is considered as a prominent way where fungi can be used for the production of nanostructures with desirable shape and size intracellularly or extracellularly. Several researchers have reported that NADH-dependent nitrate reductase enzyme plays an important role in transformation of metal ions into metal nanoparticles. The size and shape of the nanoparticles depend on the microorganism utilized and experimental condition employed during synthesis process. Nanoparticles synthesized from microbes are safe, environmental benign and have several applications in agriculture, textile, medicine, drug delivery, biochemical sensors and allied areas. Future challenges may include large-scale production, enhancement of stability, reduced time to obtain desirable shape and size and their possible applications in several fields. In this review paper, we provide a brief overview on the emerging role of fungi in the synthesis of metal nanoparticles, possible mechanisms and their potential bio-prospective applications.

Due to progress in science and technology, several harmful polycyclic aromatic hydrocarbons are synthesized and released into the environment. In the present investigation, a phenanthrene- and pyrene-degrading white rot fungi Ganoderma lucidum strain CCG1 was isolated from the Janjgir Champa district of Chhattisgarh, India, and then the degradation of phenanthrene and pyrene was estimated by high-performance liquid chromatography. It was found that G. lucidum able to degrade 99.65% of 20 mg/L of phenanthrene and 99.58% of pyrene in mineral salt broth after 30th day of incubation at 27 °C. G. lucidum produced significant amounts (p < 0.0001) of ligninolytic enzymes (Laccase, lignin peroxidase and manganese peroxidase) in the phenanthrene- and pyrene-containing mineral salt broth. G. lucidum produced maximum 10,788.00 U/L laccase, 3283.00 U/L Lignin peroxidase and 47,444.00 U/L Manganese peroxidase enzymes in the presence of phenanthrene and produced maximum 10,166.00 U/L laccase, 3613.00 U/L lignin peroxidase and 50,977.00 U/L manganese peroxidase enzymes in the presence of pyrene. Therefore, G. lucidum will be a potent phenanthrene and pyrene degrader from the environment.

In the present study silver nanoparticles fabricated by using leaf extract of Alpinia calcarata. We have also studied the effect of various experimental parameters viz., metal ion concentration, pH and incubation period on nanoparticle biosynthesis. Results of optimization showed that metal ion concentration of 1.5 mM, alkaline pH and incubation period of 12 h were the optimum conditions for metal nanoparticle biosynthesis. Synthesized silver nanoparticles were characterized by UV–Visible spectroscopy, Dynamic light scattering (DLS), Zeta potential analysis, Fourier transform infrared spectroscopy (FTIR), Inductively coupled plasma-optical emission spectrometry (ICP-OES), Transmission electron microscopy (TEM) and X-ray diffraction analysis (XRD). The UV–visible spectrum shows a sharp peak at 420 nm which was due to the surface plasmon resonance of the silver nanoparticles. Effect of several phytochemicals present in A. calcarata, on synthesis of silver nanoparticles was studied by Fourier transform infrared spectroscopy. The results indicate that the flavonoids, phytosterol, quinones and phenolic compounds present in the plant extract plays a major role in formation of silver nanoparticles in their respective ions in solution. Results of TEM and XRD analysis showed that synthesized silver nanoparticles were mostly spherical in shape with an average diameter of 27.2 ± 0.2.5 nm and highly crystalline in nature. Moreover the synthesized silver nanoparticles were also evaluated for their potential antibacterial and antioxidant activities. It showed good antibacterial activity as well as antioxidant activity. Thus the obtained result provides a scientific support that leaf extract of A. calcarata can be used efficiently in the production of potential bioactive silver nanoparticles with several pharmaceutical applications.