Abstract
One of the most important aspects of the detection of antioxidant compounds is developing a fast screening method. The screening of the overall relative antioxidant capacity (RAC) of several Romanian hydrosoluble plant extracts is the focus of this work. This is important because of the presence of increasing levels of reactive oxygen species (such as H2O2) generates oxidative stress in the human body. The consequences are a large number of medical conditions that can be helped by a larger consumption of plant extracts as food supplements, which do not necessarily contain the specified antioxidant contents. By exploiting the catalytic properties of gold nanoparticles, a specific and sensitive nanoparticle-based label-free electrochemical sensor was developed, where the working parameters were optimized for RAC screening of hydrosoluble plant extracts. First, electrochemical measurements (cyclic voltammetry and amperometry) were used to characterize different nanoparticle-based sensors, revealing the best performance of gold nanoparticle-based sensors, obtaining a RAC of 98% for lavender extracts. The sensing principle is based on the quenching effect of antioxidants for H2O2 amperometric detection, where the decrease in electrical signal suggests an increasing antioxidant capacity. The obtained results were expressed in terms of ascorbic acid and Trolox equivalents in order to be able to correlate our results with classical methods like chemiluminescence and UV-Vis spectrophotometry, where a correlation coefficient of 0.907 was achieved, suggesting a good correlation between electrochemistry and spectrophotometry. Considering these results, the optimized gold nanoparticle-based label-free sensor can be used as a simple, rapid alternative towards classical methods for relative antioxidant capacity detection of hydrosoluble plant extracts.
Highlights
Free radicals are molecules containing oxygen or nitrogen, and one or more unpaired electrons, making them very reactive
All the above biosensors have an elaborated architecture making use of several chemicals and contain enzymes or cells, which have a limited lifetime; we propose the use of a simple system, based on sensors modified with nanoparticles, towards antioxidant capacity (AC) detection, as illustrated in the graphical abstract
CNTs are the most used in electrochemical applications as they show great electrical conductivity [25], while AuNPs have the ability of electron transfer among different electroactive
Summary
Free radicals are molecules containing oxygen or nitrogen, and one or more unpaired electrons, making them very reactive. In organisms, they are referred to as reactive oxygen/nitrogen species (ROS/RNS) and are generated in metabolic and physiological processes. ROS are the radicals of hydroxyl, superoxide anion, peroxynitrite or hydrogen peroxide (H2 O2 ) and singlet oxygen [1]. The imbalance between ROS and antioxidant molecules (AOx) leads to oxidative stress (OS), which has been correlated to various disorders and medical conditions caused by damage to healthy cells, DNA and protein molecules. Oxidative stress will initiate lipid peroxidation [2].
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
