Nanoparticle production is nanotechnology's most important feature. In recent years, physical and chemical techniques to nanoparticle synthesis have shown severe flaws, necessitating the creation of an environmentally benign nanoparticle synthesis methodology. As a result, in this paper, we will detail how to synthesise magnesium oxide nanoparticles (MgONPs) from Rhizophora lamarckii and secondary chemicals found in the plant's leaf broth.