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

Abstract

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.

Optimizing hydroponic culture media and NO3−/NH4+ ratio for improving essential oil compositions of purple coneflower (Echinacea purpurea L.)

“…Nitrogen increases photosynthetic efficiency and plays an important role in increasing the amount of essential oil by increasing the number and area of leave and providing a suitable condition for receiving sunlight energy and also participating in the structure of chlorophyll and enzymes involved in photosynthetic carbon metabolism 31 . Nitrogen is an essential nutrient in plants used to synthesize many organic compounds in plants such as nucleic acids, enzymes, proteins, and amino acids, which are necessary for essential oil biosynthesis pathway 32 . Besides, essential oils are terpenoids compounds whose constituent units (isonoids) such as isopentenyl pyrophosphate and dimethyl ally pyrophosphate are strongly formed into adenosine triphosphate (ATP) and nicotinamide adenine dinucleotide phosphate (NADPH), and due to the effect of N in the production of these compounds, the amount of essential oil increased 33 .…”

Improving Essential Oil Compositions of Purple Coneflower (Echinacea Purpurea L.) Medicinal Plant Using Novel Growing Media and Nutrition Pattern in Hydroponics

“…Nitrogen increases photosynthetic e ciency and plays an important role in increasing the amount of essential oil by increasing the number and area of leave and providing a suitable condition for receiving sunlight energy and also participating in the structure of chlorophyll and enzymes involved in photosynthetic carbon metabolism (Hosseinpour et al, 2020). Nitrogen is an essential nutrient in plants used to synthesize many organic compounds in plants such as nucleic acids, enzymes, proteins, and amino acids, which are necessary for essential oil biosynthesis pathway (Banica et al, 2020). Besides, essential oils are terpenoids compounds whose constituent units (isonoids) such as isopentenyl pyrophosphate and dimethyl ally pyrophosphate are strongly formed into ATP and NADPH, and due to the effect of nitrogen in the production of these compounds, the amount of essential oil increased (Sitarek et al, 2017).…”

Increasing medicinal and phytochemical compounds of coneflower (Echinacea purpurea L.) as affected by NO3−/NH4+ ratio and perlite particle size in hydroponics

“…Besides, cichoric acid has exhibited antihyaluronidase activity, and a protective effect on the free radical-induced degradation of collagen. Cichoric acid has also been shown to have antiviral activity 5 , 6 and, recently, inhibit HIV-1 integrase and replication 7 , 8 . Echinacoside does not contribute towards the immunostimulant activity, but prospects collagen against reactive oxygen species, and also has antioxidant 9 , anti-inflammatory, and cicatrizing activities 10 .…”

“…Growing in hydroponic media may offer several advantages over field cultivation by controlling the plant nutrition requirement and facilitating the growth conditions 18 , 19 . Meanwhile, using artificial substrates in the hydroponic cultivation system reduce the cost of establishing advanced cultivation systems, and it enables the farmer to make practical use of it by using commonly raw materials such as cocopeat, sand, and vermiculite as an initial plant growing media 5 , 20 . Nevertheless, different inorganic and organic products such as peat moss, perlite, mixed materials, etc., are fully or partially used instead of initial substrates due to their useful physical properties 20 .…”