Plant-mediated synthesis of iron oxide nanoparticles has been increasingly drawing attention due to its ecofriendly nature and cost effectiveness. The biosynthesis technique engages plant secondary metabolites such as alkaloids, flavonoids, saponins, phenols, proteins, carbohydrates, glycosides, quinine, steroids, and tannins as reducers and/or stabilizers in the process of forming nanoparticles thereby replacing hazardous chemicals known with physical and chemical methods of nanomaterial synthesis. Biosynthesis method of nano particles has helped to a great extent to overcome some drawbacks, such as high energy and space requirement as well as high cost and hazard associated with various known physical and chemical methods. This work reviewed the biosynthesis of plant mediated iron oxide nanoparticles and their applications in water and wastewater treatment. Much work has been done to explore the effective, safe and cheap method for the dye removal in recent years. However, in future, more methods need to be explored to study and check the removal of dyes from wastewater using plant-mediated iron oxide nanoparticles for safer, cheaper and more efficient performance.

The present investigation on this study was to assess the antioxidant and toxicological potentials of Tapinanthus globiferus leaf extract and its effects on inherent antioxidant enzymes. The leaf extracts of the plant were prepared with both aqueous and ethanolic solvents at 5% concentration levels. Antioxidant indices such as free radical scavenging ability [DPPH], iron chelation ability [Fe 2+ ], hydroxyl radical scavenging ability [OH*], which are indices for radical scavenging potential of Tapinanthus globiferus were assessed. Toxicological effect of the plant extract was equally investigated on defensive antioxidant enzymes in rat liver. The results indicate that the extracts exhibited antioxidant properties at significant (P<0.05) levels where the radical scavenging ability of the extracts were ascertained with percentage inhibition in the range (65-41.1) % DPPH, (60-77.5) % Fe 2+ chelation, (17.5-34.2) % OH*. Hence, highest percentage inhibition was observed against Fe 2+ where the extract demonstrated high level of iron chelating ability at relatively low extract concentration (1.0mg/ml). Also the results from toxicological assay indicate synergistic effect of the extract on defensive antioxidant enzymes with concomitant increase in their activities corresponding to increase in extract concentration. The results suggest that Tapinanthus globiferus could serve as reliable antioxidant dietary supplement and perhaps not toxic at the concentrations investigated.