A study on free-radical scavenging activity, individual phenolic compounds and element concentration of propolis

The aim of this study was to assess the quality of five propolis samples obtained from Turkey (TP), China (CP), Brazil (BP1, BP2), and Ethiopia (EP). The phenolic compounds of the propolis were identified and quantified using the liquid chromatography-tandem mass spectrometry technique (LC-MS/MS). In addition, quality parameters such as total flavonoid content, total phenolic content, free-radical scavenging activity and element contents were investigated. As a result of LC-MS/MS analysis, the extracts were sorted as TP> BP1> BP2> CP> EP in terms of the total concentration of individual phenolic compounds. Chlorogenic acid was determined as the dominant compound in BP1 and EP, p-coumaric acid as the dominant compound in the BP2 and trans-ferulic acid as the dominant compound in the samples from CP and TP. The concentration of DPPH was higher in TP whereas the ABTS concentration was almost similar to other propolis extracts. The contents of potassium (K), calcium (Ca), iron (Fe), magnesium (Mg) and sodium (Na) in the propolis samples were in the range of 2416.75-14416.02 mg/kg, 8.52-613.25 mg/kg, 102.66-1425.82 mg/kg, 523.84-7336.74 mg/kg and 57.65-191.15 mg/kg, respectively. Consequently, it is again supported that chemical characteristics and activity of propolis varies according to its geographical origin with this study.