A low temperature efficient and effective method was investigated for phytochemical hydroethanolic extraction of Nasturtium officinale (Brassicaceae). The phytocompounds of the selected plant leaves were identified by high-performance liquid chromatography, gas chromatography-mass spectroscopy, Fourier transform infrared spectroscopy and ultraviolet-visible spectroscopy. Acetic acid, d-alanine, octodrine, decanoic acid, and cyclohexylethylamine were the major phytocompounds identified in N. officinale leaves with high similarity match and spectral purity. The reducing and stabilizing potential of the extracted phytochemicals was demonstrated by synthesizing the metal oxide nanoparticles (MoO NPs) by treating Ammonium heptamolybdate tetrahydrate (H MO N O .4H O) aqueous complex with bioactive compounds of the leaves. The bio-synthesized MoO nanoparticles were characterized by UV Visible spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction, energy dispersive X-ray spectroscopy, field emission-scanning electron microscopy and gas chromatography-mass spectroscopy. Gas chromatography-mass spectroscopy identified acetic acid, d-alanine, and octodrine as stabilizing agents in the synthesis of MoO NPs. This article is protected by copyright. All rights reserved.