total polyphenol contents, radical scavenging and cyclic voltammetry of Algerian propolis

Abstract

Objective: In this study, we will determine the antioxidant properties of methanolic extract of propolis from Ghardaia and Khanchla provinces of Algeria and will correlate the values with total levels of polyphenolic compounds. Methods: The total polyphenol contents of methanolic extract of propolis were measured by using Folin–Ciocalteu spectrophotometric method. Thereafter, the antioxidant properties of these polyphenols were determined by using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging. All polyphenols extracted were tested using cyclic voltammetry (CV) in aqueous media. The CV was realised to compare the results from spectroscopic method and to electrochemically characterise the propolis polyphenols. Results: The total polyphenolic content in methanolic extract of propolis from Ghardaia and Khanchla was 493.49 and 1423.32 mg gallic acid equivalent/100g of extract, respectively. The IC50 values for scavenging DPPH radical for Ghardaia and Khanchla propolis were 0.03917 mg/mL, 0.01211mg/mL respectively. Antioxidant activity measured by cyclic voltammetry method indicated that methanolic extract of Khanchla propolis had AEAC of 15,61 mg/g. Conclusion: Propolis samples had strong antioxidant activities, and the highest activities were found in Khanchla propolis. Also, among three assays employed in this study (DPPH, RP, CV), the cyclic voltammetry method was recommended as it represented a relatively clean chemical system