Flower-Based Green Synthesis of Metallic Nanoparticles: Applications beyond Fragrance

Abstract

Green synthesis has gained wide attention as a sustainable, reliable, and eco-friendly approach to the synthesis of a variety of nanomaterials, including hybrid materials, metal/metal oxide nanoparticles, and bioinspired materials. Plant flowers contain diverse secondary compounds, including pigments, volatile substances contributing to fragrance, and other phenolics that have a profound ethnobotanical relevance, particularly in relation to the curing of diseases by 'Pushpa Ayurveda' or floral therapy. These compounds can be utilized as potent reducing agents for the synthesis of a variety of metal/metal oxide nanoparticles (NPs), such as gold, silver, copper, zinc, iron, and cadmium. Phytochemicals from flowers can act both as reducing and stabilizing agents, besides having a role as precursor molecules for the formation of NPs. Furthermore, the synthesis is mostly performed at ambient room temperatures and is eco-friendly, as no toxic derivatives are formed. The NPs obtained exhibit unique and diverse properties, which can be harnessed for a variety of applications in different fields. This review reports the use of a variety of flower extracts for the green synthesis of several types of metallic nanoparticles and their applications. This review shows that flower extract was mainly used to design gold and silver nanoparticles, while other metals and metal oxides were less explored in relation to this synthesis. Flower-derived silver nanoparticles show good antibacterial, antioxidant, and insecticidal activities and can be used in different applications.

Fruit Extract Mediated Green Synthesis of Metallic Nanoparticles: A New Avenue in Pomology Applications

“…Substantial growth in this field has inclined the interest of researchers to synthesize green nanoparticles (NPs) using different parts of plants. The primary reason for synthesizing metallic nanoparticles from different parts of the plants is that the procedures are cost-effective, eco-friendly, sustainable and straightforward [ 1 , 3 ]. Metal and metal oxide NPs are considered as efficient nanoparticles as they show remarkable biomedical activity and have a high surface area to volume ratio [ 1 ].…”

“…Lately, numerous herbal species and plant extracts have been used as capping and reducing agent for synthesizing NPs, which has improved the field of nanoscience [ 1 ]. Various bacterial cells, as well as their extracts, have been comprehended for synthesizing varieties of NPs of silver (Ag), gold (Au), silver oxide (AgO), cadmium sulfide (CdS), and titanium dioxide (TiO 2 ) [ 3 ]. A few fungal species have also been reported for synthesizing NPs of Ag, CdS and TiO 2 .…”

Antioxidant Functionalized Nanoparticles: A Combat against Oxidative Stress

“…The silver nanoparticles (AgNPs), show a substantial biochemical and catalytic activity, which can be attributed to their significantly large surface area, as compared with other particles with similar chemical structures [134]. The AgNPs synthesis occurs via two steps, at first, Ag + ions are reduced to Ag • , followed by the agglomeration of colloidal silver nanoparticles, to form the oligomeric clusters which are finally stabilized [134]. Biological catalysts (enzymes) are required to reduce the Ag + ions, and the production of AgNPs with characteristic antioxidant properties can be achieved with a variety of plant extracts, as shown in Table 3.…”

“…Gold nanoparticles (AuNPs) have attained significant attention, owing to their physical characteristics (size and shape), optical properties and biocompatibility [134]. Gold nanoparticles of varied sizes and diverse morphologies have been employed in the medical sector for various purposes, such as the detection of tumors, and as a carrier for drugs etc.…”

“…Gold nanoparticles of varied sizes and diverse morphologies have been employed in the medical sector for various purposes, such as the detection of tumors, and as a carrier for drugs etc. (e.g., Paclitaxel) [134]. Antioxidant AuNPs are mostly derived from extracts of plant parts like leaves and fruits, as shown in Table 3.…”