Ultrasonic assisted propolis extraction: characterization by ATR-FTIR and determination of its total antioxidant capacity and radical scavenging ability

Abstract

In the current study, ultrasonic assisted ethanolic extract of propolis was discussed in detail, including their total phenolic content, total antioxidant capacity and radical scavenging capacity. For this purpose, we determined the total antioxidant capacity of propolis extract by CUPRAC and FRAP) assay. At the same time, the free radical scavenging capacity of propolis extracts was investigated via the DPPH• and CUPRAC- hydroxyl radical scavenging (HRS) methods. The chemical constituents of propolis extract were characterized by ATR-FTIR. The results revealed that propolis is rich in total phenolic components (189 mg GAE /g extract). According to the CUPRAC assay, the total antioxidant capacity of propolis extract was calculated to be 2.43 ± 0.07 mmol TE/g-propolis extract. FRAP value of propolis extract was determined as 1.11 mmol TE/g-propolis extract. DPPH• scavenging activity of propolis extract was calculated to be 0.71± 0.002 mmol TE / g - extract. On the other hand, according to the CUPRAC method, HRS capacity of propolis extract at different concentrations (5-10 μg/mL) was determined as 68.1% and 77.64 %, respectively. Research findings showed that propolis extract has a strong radical scavenging potential. The FTIR spectra of the functional groups originating from the phenolic compounds in the propolis extract were as expected.