SYNTHESIS AND CHARACTERIZATION OF MANGANESE OXIDE NANOPARTICLES USING RAPHIA HOOKERI EXTRACT AND ITS APPLICATIONS FOR ANTI-MICROBIAL, ANTI-INFLAMMATORY AND ANTI-OXIDANT ACTIVITIES.

ABTRACT This study focuses on the synthesis and characterization of manganese oxide nanoparticles (MnO₂NPs) and evaluates their potential applications in antimicrobial, anti-inflammatory, and antioxidant activities. MnO₂NPs were synthesized using a green synthesis approach, ensuring environmentally friendly and cost-effective production. The MnO2NPs was characterized using the UV-Visible spectrophotometry, Fourier Transform Infrared Spectrophotometry (FTIR), Energy Dispersive Spectrometry (EDX), Powdered X-ray Diffractometry (PXRD), Scanning electron microscpopy (SEM) and Transmission Electron Microscopy (TEM). UV-Visible spectrum revealed that MnO2NPs showed maximum absorption at wavelength of 402 nm in the visible region. FTIR results showed prominent reactive functional groups for hydroxyl (-OH) at 3391.30 cm−1 and a weak carbonyl (-C=O) at 1743.00 cm−1. The EDX results revealed the elemental composition in percentages of the elements in the nanoparticles, showing Mn (83.17 %), O (14.31 %) and C (5.54%) respectively. PXRD revealed that the manganese dioxide nanoparticle is in a crystalline state with respect to its intense multiple peaks. The morphology of the synthesized nanoparticle was found regularly spherical and with porous surface for SEM. The average particle size of the nanoparticles as characterized by TEM was found to be 25.2 nm. The nanoparticles demonstrated significant antimicrobial efficacy against a range of pathogenic microorganisms, underscoring when compared to conventional antibiotics. Additionally, MnO₂NPs exhibited strong anti-inflammatory properties at the highest concentration of 150 μg/mL for both the nanoparticle and the diclofenac control showing 57.96 % and 89.13 % respectively. Their antioxidant activity was also prominent, as evidenced by their ability to scavenge free radicals and mitigate oxidative stress by scavenging excellently with an IC50 of 64.92 ± 0.04 μg/mL which is considerably lower and thus more active than the standard ascorbic acid: 527.17 ± 0.29 μg/mL at highest concentration of 500 μg/mL. The study highlights the multifunctional properties of MnO₂NPs and their potential use in biomedical and pharmaceutical applications, offering a promising avenue for developing novel therapeutic agents.