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Open AccessArticle

Determination of the Total Polyphenols Content and Antioxidant Activity of Echinacea Purpurea Extracts Using Newly Manufactured Glassy Carbon Electrodes Modified with Carbon Nanotubes

1
Department of Pharmacy, Faculty of Medicine and Pharmacy, University of Oradea, 29 N. Jiga St., 410028 Oradea, Romania
2
Chitkara College of Pharmacy, Chitkara University, Punjab 140401, India
3
Faculty of the Physical Culture, Palacký University Olomouc, 77111 Olomouc, Czech Republic
4
Department of Analytical Chemistry, Faculty of Applied Chemistry and Materials Science University Politehnica of Bucharest,1-7 Polizu St., 011061 Bucharest, Romania
5
Department of Preclinical Disciplines, Faculty of Medicine and Pharmacy, University of Oradea, 410073 Oradea, Romania
*
Authors to whom correspondence should be addressed.
Processes 2020, 8(7), 833; https://doi.org/10.3390/pr8070833
Received: 17 June 2020 / Revised: 7 July 2020 / Accepted: 8 July 2020 / Published: 13 July 2020
A sensitive electrochemical method was used for the determination of the total phenolic content and antioxidant activity of Echinacea purpurea extracts. In this study, 3 glassy carbon electrodes (GCE) were used: one unmodified and the other two newly manufactured glassy carbon electrodes modified with carbon nanotubes (CNTs) and chitosan (CS) in different concentrations, having the following composition: 1 mg/mL CNTs/CS 5%/GCE and 20 mg/mL CNTs/CS 0.5%/GCE. The determinations were performed on 3 different pharmaceutical forms (capsules, tablets and tincture), which contain E. pururea extract from the root or aerial part of the plant. Standard chicoric and caftaric polyphenolic acids, as well as food supplements extracts, were characterized using voltammetry, in a Britton-Robinson (B-R) electrolyte buffer. The modified 1 mg/mL CNTs/CS 5%/GCE electrode has superior properties compared to the other two (the unmodified and 20 mg/mL CNTs/CS 0.5%/GCE-modified) electrodes used in the study. Echinacea tincture had the highest antioxidant capacity and the biggest total amount of polyphenols (28.72 mg/equivalent of 500 mg powder). Echinacea capsules had the lowest antioxidant capacity, but also the lowest total amount of polyphenols (19.50 mg/500 mg powder); similarly, tablets had approximately the same values of polyphenols content (19.80 mg/500 mg powder), and also antioxidant capacity. The total polyphenol content was consistent with the one indicated by the manufacturers. Pulse-differential cyclic voltammetry represents a rapid, simple and sensitive technique to establish the entire polyphenolic amount and the antioxidant activity of the E. purpurea extracts. View Full-Text
Keywords: polyphenols; antioxidant activity; Echinacea purpurea extracts; glassy carbon electrode (GCE); carbon nanotubes (CNTs) polyphenols; antioxidant activity; Echinacea purpurea extracts; glassy carbon electrode (GCE); carbon nanotubes (CNTs)
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MDPI and ACS Style

Banica, F.; Bungau, S.; Tit, D.M.; Behl, T.; Otrisal, P.; Nechifor, A.C.; Gitea, D.; Pavel, F.-M.; Nemeth, S. Determination of the Total Polyphenols Content and Antioxidant Activity of Echinacea Purpurea Extracts Using Newly Manufactured Glassy Carbon Electrodes Modified with Carbon Nanotubes. Processes 2020, 8, 833. https://doi.org/10.3390/pr8070833

AMA Style

Banica F, Bungau S, Tit DM, Behl T, Otrisal P, Nechifor AC, Gitea D, Pavel F-M, Nemeth S. Determination of the Total Polyphenols Content and Antioxidant Activity of Echinacea Purpurea Extracts Using Newly Manufactured Glassy Carbon Electrodes Modified with Carbon Nanotubes. Processes. 2020; 8(7):833. https://doi.org/10.3390/pr8070833

Chicago/Turabian Style

Banica, Florin; Bungau, Simona; Tit, Delia M.; Behl, Tapan; Otrisal, Pavel; Nechifor, Aurelia C.; Gitea, Daniela; Pavel, Flavia-Maria; Nemeth, Sebastian. 2020. "Determination of the Total Polyphenols Content and Antioxidant Activity of Echinacea Purpurea Extracts Using Newly Manufactured Glassy Carbon Electrodes Modified with Carbon Nanotubes" Processes 8, no. 7: 833. https://doi.org/10.3390/pr8070833

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