Bio-fabrication of Gold Nanoparticles by Root Extract of Asparagus racemosus and their Potential Biomedical Applications

Introduction: The biosynthesis of gold nanoparticles (AuNPs) is a rapidly developing field that integrates biological systems with nanotechnology to produce nanoparticles with unique properties. This study aimed to biosynthesize gold nanoparticles using Asparagus Racemosus root extract (popularly known as Shatavari root aqueous extract) (AR-AuNPs), to characterize the AuNPs spectrally, and to explore their potential applications. Methods: AuNPs were synthesized using Shatavari extract, leveraging its polyphenolic content for the reduction of gold ions. The formation of nanoparticles was confirmed using UV-Vis spectroscopy, with a surface plasmon resonance peak at 550 nm. Further characterization was performed using electron microscopy to assess size and morphology, X-Ray Diffraction (XRD) to analyse the crystalline structure, Fourier-Transform Infrared Spectroscopy (FTIR) to identify functional groups, and Dynamic Light Scattering (DLS) to determine particle size and zeta potential. Results: The bio-synthesized gold nanoparticles are spectrally characterized; the size of the gold nanoparticles is below 50 nm, and they reveal very good biomedical applications. The biosynthesized AR-AuNPs exhibited strong antioxidant activity, with the nitric oxide (NO) scavenging method proving superior to the DPPH and H2O2 assays. While the antimicrobial activity of ARAuNPs was limited against both Gram-positive and Gram-negative bacteria, they showed effective DNA binding activity. Discussion: The synthesized gold nanoparticles exhibited a characteristic UV-Vis absorption peak at 550 nm, confirming their successful formation. Dynamic Light Scattering (DLS) analysis revealed an average particle size of 44.7 nm, and the zeta potential was measured at -14.3 mV, indicating moderate stability. The polyphenols present in the aqueous extract of Shatavari plant roots likely played a role in both the reduction and stabilization of the AuNPs. When tested on A549 cell lines, the AR-AuNPs demonstrated significant antiproliferative activity, with an IC50 value of 68.99 μM, compared to Cisplatin. However, they lacked anticancer activity against MCF-7 cell lines. The biosynthesized AR-AuNPs exhibited strong antioxidant activity, moderate antimicrobial activity, and effective DNA binding activity. Conclusion: Biosynthesizing AuNPs using Shatavari extract is a green, sustainable method that produces nanoparticles with desirable properties for various applications. The synthesized AuNPs exhibit promising capabilities in the fields of medicine and environmental science, positioning them as valuable tools for future research. Further studies are needed to explore their potential in real-world applications.