Cyclic voltammetry and UV/Vis spectroscopy in combination with multivariate data analysis for the assessment of authenticity of poplar type propolis

Electrochemical Methods for Evaluation of Antioxidant Properties of Propolis Extract Incorporated in Chitosan Nanoparticles

“…Three anodic peaks and one cathodic peak appeared in the CVs registered for nanopropolis, similar results being also reported by other authors for different propolis extracts [26][27][28]30]. The oxidation peaks from around 400 mV, 600 mV and 800 mV, respectively were assigned to the flavonoids electrochemical oxidation, while the first oxidation peak having the highest intensity was assigned to the catechol groups, as already reported by other authors [27][28]30]. The antioxidant potential of nanopropolis was evaluated based on the ascorbic acid equivalent antioxidant capacity (AEAC).…”

“…Meanwhile ascorbic acid presents absorbance at 260 nm [53]. The peaks from the UV-Vis spectra confirmed the phenolic compounds from propolis extract and nanopropolis revealed by the HPLC analysis, knowing from the literature that these compounds are visible in the range 280-350 nm [2,[26][27]. According to the classification of propolis types mentioned by Marghitas et al [2], the propolis extract could be integrated in type 3 (with a total flavonoid content of 5-8%), meanwhile the nanopropolis could be included in type 2 (with approximatively 5% of total flavonoid content).…”

“…UV-Vis spectra of propolis extract and nanopropolis were recorded observing peaks at 300 nm (corresponding to the aqueous propolis extract) and at 290 nm and 310 nm (for the nanopropolis sample) (Figure 8), similarly with other types of propolis from some studies [2,[26][27]. Meanwhile ascorbic acid presents absorbance at 260 nm [53].…”

“…The main drawbacks of these methods are related to the high cost of reactants and different interferences with other colorful compounds in the sample. Another spectroscopic approach is the determination of total content of flavonoids by UV-Vis analysis [22][23][24][25], while the UV-Vis characterization of the propolis extract pointed out the content of phenolic compounds with π conjugated aromatic rings [26][27]. The advantages of electrochemical methods result from the relationship between electrochemical behavior and antioxidant power of phenolic compounds: a low oxidation potential is associated with a high antioxidant power [28].…”

“…The advantages of electrochemical methods result from the relationship between electrochemical behavior and antioxidant power of phenolic compounds: a low oxidation potential is associated with a high antioxidant power [28]. The electrochemical method is based on the measurement of anodic current intensity, which is related to the total content of the reducing species present in the sample, and hence, is considered a rapid, easy and low cost tool for evaluation of antioxidant capacity of propolis extracts from different origins [26][27][28][29][30][31].…”