Implementation of National Education Policy -2020: Multidisciplinary Education ISBN: 978-93-94819-23-8 Pub. Date: 12/02/2023 Volume: I 39 “A Review on Biomedical Approaches of Green Synthesized Cerium Oxide Nanostructure” Sumaiyya M. Patel, Vaishali D.Murade, , Shobha A. Musmade,Dinesh P. Hase, Surekha K. Kadu, Gajanan R. Pandhare Padmashri Vikhe Patil College of Arts, Science and Commerce, Pravaranagar, Ahmednagar (MS) Corresponding Author : Sumaiyya M. Patel Abstract: CeO2 nanoparticles (NPs) have shown promising approaches as therapeutic agents in biology and medical sciences. Also CeO2 show the different antioxidant properties, this is mainly due to the self-regeneration of their surface, which is based on redox-cycling between 3+ and 4+ states for cerium, in response to their immediate environment.The aim of this review is to discuss the green synthesis methods and the different biomedical applications like antioxidant, anticancer, antibacterial activities and toxicological studies including the most recent studies carried out in vivo and in vitro to study the problems. The greener approach provides environment friendly, non- toxic, cost effective and efficient method for the production of metal oxide nanoparticles. This review focused on the biosynthesis of CeO2and its potential biological applications. Key Words: Cerium oxide, green synthesis of CeO2, biomedical applications Introduction: Nanotechnology is the branch of science which deals with particles ranging between 1–100 nm. These particles are called nanoparticlesand they exhibit unique electronic, optical, magnetic, and mechanical properties, which make them different from the bulk material. These properties of nanomaterials help them to find a variety of applications in the biomedical, agricultural, and environmental fields[1, 2, 3]. By considering variety of applications,different synthetic approaches have been used for the fabrication of nanoparticles with desired the morphology and size. To achieve nanoparticles of desired morphology, two different basic approaches of synthesis have been studied in the existing literature such as top- down approach and bottom-up approach [4]. Conventionally, nanoparticles are synthesized through a diverse range of preparation methods such as ball milling, sputtering, lithographic techniques, and etching The utilization of the bottom-up approach involves various protocols such as sol–gel process, molecular/atomic condensation, chemicals’ vapor deposition, laser pyrolysis, and spray pyrolysis[5]. Among the various approaches and protocols used for the synthesis of CeO2 NPs, the synthesis using biosources as a reducing agent has been generally accepted by researchers because of eco-friendliness, nonhazardous reagents, easy to operate procedures, low energy consumption, and cost effectiveness. Biomolecules and secondary metabolites present in plant extracts, such as tannins, flavanones, saponins, polyphenols, alkaloids, and terpenoids, have been reported to be responsible for the effective reduction of cerium precursors[6]. This green synthesis not only produces highly efficient Nano carriers but also performs its specified work without disturbing living organisms or the environment. This type of synthesis process is less time consuming as compared to physicochemical methods.CeO2 NPs mediated from plant extracts have better antimicrobial potential against human pathogens and infections caused by bacteria and fungi [7]. CeO2 nanoparticles (NPs) have attained significant consideration in Nanomedicine because of their promising applications in drug delivery, catalysis, bio-sensing, and medicine. CeO2 nanoparticles are relatively stable, have exceptional biocompatibility with little or no toxicity, low cost, and are environmentally friendly[8]. Cerium has two oxidation states such as tetravalent (Ce 4+ ) and trivalent (Ce 3+ ). Therefore, cerium oxide exists as two different oxides like Ce2O3 (Ce 3+ ) and CeO2 (Ce 4+ ) depending on the nature of the materials[9, 10]. Moreover, the emergence of drug-resistant microorganisms created serious problems in treating infections and other diseases. The need to develop different and effective bactericidal agents to deal with drug- resistant bacteria is a challenge and recent studies demonstrated that metal oxide