Biogenic synthesis of gold nanoparticles using Heliotropium eichwaldi L and neuroprotective potential via anticholinesterase inhibition in rat brain

Abstract

Funding information Higher Education Commission of PakistanNanoparticles (NPs) are the fundamental backbone of nanotechnology due to their wide biomedical applications. Biogenic synthesis of gold NPs (AuNPs) using plant extracts are beneficial due to their nontoxicity, eco-friendliness, and simplicity. In this study, the HE-AuNPs were synthesized using Heliotropium eichwaldi L (HE) extract and then characterized by UV-visible (UV-vis) spectroscopy, Fourier transform-infrared (FT-IR), scanning electron microscope (SEM), X-ray diffractometer (XRD), and electron diffraction X-ray spectroscopy (EDX) analysis. UV-vis spectroscopy revealed a sharp peak λ max 567 nm, FT-IR analysis confirmed the existence of different coating and reducing organic molecules, SEM analysis showed the elongated rod-shaped morphologies with 20 nm size, XRD analysis authorized the crystalline structure of AuNPs with an average size of 11.11 nm for four key peaks (38.31 , 44.39 , 64.76 , and 77.65 ), and EDX analysis revealed that Au (44.33%) was the main element of AuNPs compared to other surface coated elements C (35.05%) and O (20.62%). The influence of various intrinsic factors like pH, temperature, metal salt, HE extract, contact time, and stability period was also studied by UV-vis spectroscopy. Moreover, the AuNps were evaluated for their anticholinesterase (anti-AChE) potential to treat Alzheimer's disease (AD). HE-AuNPs exhibited superb anti-AChE activity (67 ± 0.03%) with 88 ± 0.31 μg IC 50 , compared to pure Au salt, which showed 7 ± 0.22% inhibition. According to the Lineweaver-Burk plot, HE-AuNPs inhibit AChE noncompetitively, that is, K m remains unchanged, whereas V max decreased from 20 to 6.24 (42.4% to 82%). HE-AuNPs do not affect K Iapp , whereas increased V maxiapp from 17.5 to 29 (13% to 86.4%). The K m (Michaelis-Menten kinetic constants), K I (dissociation constant), and K i (inhibitory constant) were found to be 0.041 mM, 66 μg, and 25 μg, respectively. Overall, our results highlighted the HE-AuNPs promising latent as anti-AChE, and the green methodology allows us to suggest these NPs as suitable agents for the development of drugs helpful in the treatment of AD.

Bio‐fabrication and characterization of nano‐silver using Kickxia elatine plant and its anti‐diabetic effect on alloxan‐induced Sprague Dawley rats — An in vivo approach

“…The presence of AgNPs is confirmed by the SPR bands in the 400 to 460 nm range 89 . These results are also supported by earlier literature 90 …”

“…89 These results are also supported by earlier literature. 90 According to scientific studies, FTIR is the best method for predicting functional groups. In this study, numerous vibrational stretches were observed at varied peaks that are related to phenolic, alcoholic, aromatic, carbonyl compounds of the protein, alkynes, conjugated aldehydes, ester, ether, carboxylic acid, aliphatic amines and halo compounds.…”

Antioxidant, antidiabetic, and anti‐Alzheimer performance of green synthesized silver, gold, and silver/gold bimetallic nanoparticles

“…The significant AChE inhibition by BNPs as related to other tested inhibitors is due to their size, surface area, and shape, and AD is best treated by combining a mixture of two different metals due to their collaborative effect. Sher and Ahmed et al, Wang et al, and Sher and Alkhalifa et al [90][91][92] reported that NPs exhibited anti-AChE activity by adsorption or interaction with the enzyme. According to Sher and Ahmed et al and Rajakumar et al, 89,93 because of the NPs' lipophilicity and enzyme molecules' hydrophobicity, the NPs exhibited attraction to the AChE enzyme.…”

Acetylcholinesterase Activity in the Brain of Rats: Presence of an Inhibitor of Enzymatic Activity in Heliotropium eichwaldi L. Induced Silver/Gold Allied Bimetallic Nanoparticles

“…According to Ref. [53], Ag NPs have binding affinity to the AChE enzyme because of their lipophilicity and the hydrophobicity of the environment of the AChE molecules. The results of the present study are also in good accordance with a previous report [54].…”