Analysis of different geographic origin beecollected pollen using spectrophotometric and chromatographic techniques

Abstract

The main aim of this study was to investigate and to identify biologically active compounds in bee-collected pollen from different geographic origin by means of spectrophotometric and chromatographic techniques. Bee pollen extractions were prepared by adding 20 ml of 80% methanol to 2 gram of raw material and 24 hour shaking in orbital shaker. The methanol extracts were filtered. Spectrophotometric methods were used to determine the total amount of phenolic compounds, flavonoids and antioxidant activity. The phenolic compounds content was determined using Folin–Ciocalteu method. It varied between 24.11 and 43.89 mg RE/g. The highest content of phenolic compounds was found in monofloral CHN_1 pollen 43.89 mg RE/g. The lowest content was found in polyfloral CHN_2 pollen - 24.11 mg RE/1 g. Similar tendency was observed for spectrophotometrically determined flavonoids content and total 2,2 – diphenyl – picrylhydrazyl (DPPH•) radical scavenging activity. Flavonoids content varied from 6.62 to 12.30 mg RE/g, free radical scavenging activity was in the range from 7.89 to 35.59 mg RE/g. Total amount of phenolic compounds showed strong correlation with antioxidant activity (correlation coefficient was 0.8507). For qualitative and quantitative analysis of bee pollen flavonoids a high performance liquid chromatography with electrochemical detection (HPLC-ED) was used. Four flavonoids were identified in all bee pollen samples: rutin, 2-hydroxycinnamic acid, naringenin and quercetin.