Abstract
Saponins are bioactive compounds belonging to the secondary metabolism of plants widely used for their beneficial actions to human health. In this work the association of the saponin from Glycyrrhiza glabra with a matrix of multi-walled carbon nanotubes was promoted to obtain a composite material with improved functional characteristics. For this investigation, chemically modified electrodes (CME) based on carbon paste were developed. Firstly, a carbon paste electrode (CPE) modified with the addition of saponin (SAP) was developed. For the electrochemical optimization of this system, CPE/SAP, studies were carried out using cyclic voltammetry. The determination of parameters such as formal potential (Eo) and potential separation (?E) indicated that the saponin used as a carbon paste modifying agent generated a matrix that favors the transfer of electrons even at low applied potentials. The second step was performed by preparing the modified carbon paste electrode with the carbon nanotube matrix (CPE/CNT). This material, surprisingly, showed a redox pair probably due to the presence of iron atoms from the preparation method, something very beneficial for the purposes of this work. Next the saponin was associated to the carbon nanotube matrix in order to investigate the behavior of the hybrid material formed (CPE/SAP-CNT), which evidenced a significant improvement in the electron transfer process when the saponin interacts with the carbon nanotube matrix, increasing the anodic peak current by more than 3.6 times in relation to the CPE/SAP and 2.1 times when compared to the CPE/CNT. Another important issue concerns the stability of the systems, with the saponin associated with the carbon nanotube matrix presenting significantly improved stability, being able to be used for more than 8 hours or 200 voltammetric cycles with loss of signal of the order of only 2%, while the CPE/SAP showed a 60% loss of signal under the same conditions of use.
Highlights
The study of the electrochemical behavior of bioactive compounds has grown significantly in recent years, especially as a modifying agent in working electrodes, so-called chemically modified electrodes (CME) often associated with matrices of materials such as carbon nanotubes and other nanomaterials used in the development of amperometric sensors or biosensors
De Oliveira et al [27] investigated the interaction between the triblock copolymer Pluronic F127 and a natural bioactive amphiphilic saponin extracted from Glycyrrhiza glabra roots
These results indicate the formation of micelle-like complexes, with structure dependent on the SAP concentration, as highly promising agents in nanobiotechnology applications
Summary
The study of the electrochemical behavior of bioactive compounds has grown significantly in recent years, especially as a modifying agent in working electrodes, so-called chemically modified electrodes (CME) often associated with matrices of materials such as carbon nanotubes and other nanomaterials used in the development of amperometric sensors or biosensors. The great effort that is made in the search for better electrochemical sensors occurs, since they are devices with peculiar characteristics, which present themselves with increasing use, with data in experimental conditions obtained, with good precision and accuracy, possibilities of miniaturization and, allow obtaining important information in different systems, increasing its applicability ranging from the detection of gas molecule to the study of the kinetics of chemical signals from a biological cell to implanted sensors [4, 6, 7]. In terms of chemical structure they are described as a group of triterpenic or steroidal glycosides predominantly found in the plant kingdom, in different parts of plants, including roots, shoots, flowers, seeds and leaves and to a lesser extent in marine animals [10,11,12,13]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
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 call
