DETERMINATION OF ANTIOXIDANT CAPACITY (ORAC) OF GREIGIA SPHACELATA AND CORRELATION WITH VOLTAMMETRIC METHODS

Background: Dopamine agonists are useful drugs for the management of patients with Parkinson's disease in the early stages and in later stages of the disease. Parkinson's disease is a progressive neurodegenerative disease that primarily affects dopamine-producing nerve cells in the brain. They bind to dopamine receptors in nerve cells that regulate body movement and motor function. Electroanalytical methods are used in medicinal, clinical and pharmaceutical research. The voltammetry is one of the most commonly used electroanalytical methods. The aims of this review are to gather and discuss studies of voltammetric methods used in determination of dopamine agonists. Method: This review includes the use of various voltammetric methods for determination studies of dopamine agonists from pharmaceutical dosage forms and biological samples. These studies were examined in terms of used voltammetric method or methods, working electrode, buffer, pH and validation parameters. Results: Cabergoline, pramipexole, ropinirole have more studies, while bromocriptine and apomorphine have fewer studies in the literature. Differential pulse voltammetry and square wave voltammetry methods were the most applied methods for determination of dopamine agonist drugs from pharmaceuticals and biological samples. But, stripping, cyclic and lineer sweep voltammetry methods are less applied methods. In this studies, a lot of modified electrodes were developed and used to analyse of dopamine agonists. Conclusion: The voltammetric methods supply determination of therapeutic agents and/or their metabolites in clinical samples at extremely low concentrations without the necessity for the sample pre-treatment or time consuming extraction steps. Also the modified electrodes and validated voltammetric methods provide good stability, repeatability, reproducibility and high recovery for the analysis of the analyte.

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Determination of antioxidant activity and phenolic compounds for basic standardization of Turkish propolis

Applied Biological Chemistry ◽

10.1186/s13765-021-00608-3 ◽

2021 ◽

Vol 64 (1) ◽

Author(s):

Aslı Özkök ◽

Merve Keskin ◽

Aslı Elif Tanuğur Samancı ◽

Elif Yorulmaz Önder ◽

Çiğdem Takma

Keyword(s):

Antioxidant Capacity ◽

Caffeic Acid ◽

Caffeic Acid Phenethyl Ester ◽

Total Phenolic ◽

Scaling Analysis ◽

Flavonoid Content ◽

Multidimensional Scaling Analysis ◽

Flavonoid Quercetin ◽

Phenolic And Flavonoid

AbstractThis study aimed to determine the standard amount of antioxidant content and compounds of the propolis for the standardization of propolis. For this purpose, the total flavonoids, total phenolic, CUPRAC antioxidant capacity content and the diversity of phenolic and flavonoid components of these propolis samples were found by HPLC determined at the 23 propolis samples which were collected different regions of Turkey. Beside that, the similarities and differences of these 23 provinces to each other according to their antioxidant capacities were investigated by multidimensional scaling analysis. The total flavonoid content in the propolis samples were determined between 21.28 and 152.56 mg CE/g. The total phenolic content in the propolis samples was found between 34.53 mg and 259.4 mg GAE/g. CUPRAC antioxidant capacity of the propolis samples and antioxidant range was found from 95.35 to 710.43 mg TE/g. Also, 4 flavonoid [Quercetin (min.1.12–max.4.14 mg/g), Galangin (min.0.72–max.40.79 mg/g), Apigenin (min.1.07–max.17.35 mg/g), Pinocembrin (min.1.32–max.39.92 mg/g] and 6 phenolic acid [Caffeic acid (min.1.20–max.7.6 mg/g), p-Coumaric acid (min.1.26–max.4.47 mg/g), trans-Ferulic acid (min.1.28–max.4.92 mg/g), Protocatechuic acid (1.78 mg/g), trans-Cinnamic acid (min.1.05–max.3.83 mg/g), Caffeic Acid Phenethyl Ester (CAPE) (min.1.41–max.30.15 mg/g)] components were detected as mg/g, in different ratios in propolis samples collected from different regions. The feature of this study, so far, is to have the maximum number of samples representing the Turkish propolis, and so is thought to help to national and international propolis standard workings.

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