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In this study, it was aimed to determine the in vitro antioxidant and enzyme inhibitory activities of methanol (MeOH) extracts isolated from Onosma gracilis (Trautv.) and O. oreodoxa (Boiss. & Heldr.). O. oreodoxa was found to be richer in both phenolics and flavonoids than O. gracilis. The amounts of total phenolics and flavonoids in O. oreodoxa were 53.76 mg GAEs/g and 25.29 mg QEs/g, respectively. In addition to spectrophometric analysis, in chromatographic analyzes, twenty-four and twenty-six compounds were identified in O. gracilis and O. oreodoxa, respectively. High amounts of hesperidin (6647.2 and 5260.75 µg/g extract, respectively), hyperoside (7153.26 and 10216.74 µg/g extract, respectively) and rosmarinic acid (21824.33 and 87493.19 µg/g extract, respectively) were found in O. gracilis and O. oreodoxa. While O. oreodoxa showed higher activity in cupric reducing antioxidant power (CUPRAC), ferric reducing antioxidant power (FRAP), phosphomolybdenum, 1, 1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging, and ferrous ion chelating assays (324.22, 175.41, 719.50, 125.60 mg TEs/g extract and 25.11 mg EDTAEs/g extract, respectively), ABTS radical scavenging activity of O. gracilis (164.55 mg TEs/g extract) was higher than that of O. oreodoxa. O. gracilis also exhibited higher inhibitory activity on acetylcholinesterase (AChE), butyrylcholinesterase (BChE) (2.57 mg GALAEs/g extract) and α-glucosidase (1674.24 mg ACEs/g extract). On the other hand, the sample showing the most effective inhibition on α-amylase and tyrosinase was O. oreodoxa (417.34 mg ACEs/g extract and 136.18 mg KAEs/g extract, respectively). As a result of the molecular docking analysis performed to determine the contribution of hesperidin, hyperoside and rosmarinic acid to the enzyme inhibitory activity, the binding affinity and inhibition constant of hyperoside to all enzymes were quite high and therefore it was concluded that it may be the compound that contribute to the activity.

Brown HT and carmoisine, which are the most used dyestuffs in pharmaceuticals, textiles, cosmetics and foods, are important components of the Azo family. Although the Azo group is not toxic or carcinogenic under normal conditions, these dyestuffs require great care due to the reduction of the Azo functional group to amines. In particular, fast, reliable, easy, on-site and precise determinations of these substances are extremely necessary and important. In this review, the properties, applications, and electrochemical determinations of brown HT and carmoisine, which are used as synthetic food colorants, are discussed in detail. Up to now, sensor types, detection limits (LOD and LOQ), and analytical applications in the developed electrochemical strategies for both substances were compared. In addition, the validation parameters such as the variety of the sensors, sensitivity, selectivity and electrochemical technique in these studies were clarified one by one. While the electrochemical techniques recommended for brown HT were mostly used for the removal of dyestuff, for carmoisine they included fully quantitative centered studies. The percentiles of voltammetric techniques, which are the most widely used among these electroanalytical methods, were determined. The benefits of a robust electrochemical strategy for the determination of both food colors are summed up in this review. Finally, the brown HT and carmoisine suggestions for future perspectives in electrochemical strategy are given according to all their applications.

Although there are many definitions of antioxidants, the most general description; antioxidants are carried a phenolic function in their structure and prevent the formation of free radicals or intercept from damage to the cell by scavenging existing radicals. Moreover, they are one of the most effective substances that contain essential nutrients for healthy individuals. The importance of these antioxidants, which have an incredible effect on the body and increase the body’s resistance, is increasing day by day for healthy individuals. Numerous studies have been carried out for antioxidants with excellent properties and however new, reliable, selective, sensitive and green analytical methods are sought for their determination at trace levels in food samples. Along with the latest developments, electrochemical methods are of great interest in the world of science because they are fast, reliable, sensitive and environmentally friendly. Electrochemical methods have been frequently applied to analyze antioxidant capacity in many nutrients samples found in different forms such as solid, liquid without any pretreatment applications in the last decade. Furthermore, these methods are preferred because of the short analysis time, the ability to lower detection limits, reduction in a solvent, high sensitivity, portability, low sample consumption, wide working range, and more economical than existing other traditional analytical methods. The antioxidant sensing applications by modern electrochemical methods such as cyclic, square wave, differential pulse, and combined with stripping voltammetric techniques were used to deduce antioxidant capacity (AC) in critical nutrients. Moreover, this chapter includes a description of the classification of electrochemical methods according to the working electrode type, dynamic working range, limit of determination (LOD), limit of quantification (LOQ), sample type, and using standard analyte and so forth for each voltammetric methods. While many articles applied for the determination of antioxidant sensing by electrochemistry have gained momentum in the last two decades, we focused on the studies conducted over the last 4 years in this chapter.

This study provides a comprehensive review of the latest developments in the electrochemical impressions of the important dyestuffs including amaranth and carminic acid. Food colors are organic substances that have important effects on human health and food safety. While these substances do not pose a problem when used in the daily intake (ADI) amounts, they harm human health when consumed excessively. Amaranth and carminic acid are synthetic and natural food colors ingredients, respectively. Analysis of these substances in food, pharmaceutical, cosmetic and textile samples is extremely important because of their genotoxicity, cytostatic and cytotoxic effects. Electroanalytical methods, which have great advantages over traditional analytical methods, shed light on the scientific world. Electrochemical monitoring modules, which are fast, simple, accurate, reliable, and highly selective, are promising for the determination of both substances. Until now, amaranth and carminic acid food determinations have been carried out successfully with electrochemical monitoring techniques in many numbers in the literature. Voltammetric techniques are the most widely used among these electroanalytical methods. In particular, square wave and differential pulse voltammetric techniques, which have extraordinary properties, have been heavily preferred. Limits of detection (LOD) comparable to the standard analytical method have been achieved using these methods, which have very quick analysis durations, high precision and accuracy, do not require long preprocessing, and have great selectivity. In addition, more sensitive and selective analyses of amaranth and carminic acid in natural samples were carried out with numerous indicator electrodes. The merits of powerful electrochemical monitoring studies for the determination of both food colors during the last decade are presented in this study. Moreover, parameters such as analytical applications, detection limits, electrochemical methods, selectivity, working electrodes, and working ranges are summarized in detail.