Bioactive compounds from medicinal plants can enhance the therapeutic potential of trace metal-oxide nanoparticles. This study contributed to identifying the main volatile compounds and synthesizing manganese dioxide nanoparticles (MnO2 NPs) using Moringa oleifera (MO) leaf extract and explored their biological applications. Gas chromatography-mass spectrometry (GC-MS) analysis identified 21 volatile compounds with known bioactivities from the leaves of MO. Transmission electron microscopy (TEM) and x-ray diffraction analysis showed that MnO2 NPs were spherical and crystalline, averaging ∼8.3 nm in size. Antioxidant activity, assessed by 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assays, revealed high potency (IC50 = 9.08 ± 0.11 and 6.62 ± 0.12 µg/mL). Cell viability assays indicated relative non-toxicity, with IC50 values greater than 20 µg/mL for human embryonic kidney (HEK 293) and liver (HEPG2) cells. The antidiabetic effects were evaluated against α-amylase and α-glucosidase enzymes, showing IC50 values of 36.58 ± 0.74 and 55.03 ± 1.68 µg/mL, respectively, compared to FDA-approved acarbose. Docking studies yielded scores of -6.10 and -7.32 kcal/mol. Overall, these results highlight that the MO-synthesized MnO2 NPs can be explored as potential antioxidant, cytoprotective, and antidiabetic agents for therapeutic uses.
Mahlo et al. (Sun,) studied this question.