Facile Green Synthesis of Titanium Dioxide Nanoparticles by Upcycling Mangosteen (Garcinia mangostana) Pericarp Extract

In the present report, green synthesis of titanium dioxide nanoparticles (TiO 2 NPs) was performed by upcycling mangosteen ( Garcinia mangostana ) pericarp extract (methanol and ethyl acetate extracts). Field emission scanning electron microscopy images revealed an aggregated structure with a highly porous network of TiO 2 NPs. TiO 2 NPs synthesized with ethyl acetate extract (EtOAc-TiO 2 NPs) exhibited more monodispersity and possessed smoother surfaces than the control TiO 2 NPs (Con-TiO 2 NPs) and TiO 2 NPs synthesized with methanol extract (MeOH-TiO 2 NPs). High-resolution X-ray diffraction patterns clearly confirmed that TiO 2 NPs had a crystalline nature. A mixture of anatase and rutile was observed in Con-TiO 2 NPs and MeOH-TiO 2 NPs, while EtOAc-TiO 2 NPs had only anatase with the smallest size (12.50 ± 1.81 nm). Ethyl acetate extract contained the highest amount of α-mangostin; thus, the surface of TiO 2 NPs was functionalized with ethyl acetate extract. The functionalized TiO 2 NPs synthesized with ethyl acetate extract (EtOAc-TiO 2 -αm) showed the highest 2,2-diphenyl-1-(2,4,6-trinitrophenyl)hydrazyl (DPPH) radical scavenging activity. In vitro cell viability on mouse fibroblast cells (NIH3T3) indicated that the newly synthesized TiO 2 NPs did not show any significant cytotoxicity. Therefore, the TiO 2 NPs in the present report have the potential to be used in cosmetic applications such as sunscreens.