Characterization of chemical compounds of fractions from four different bee pollens with chemometric classification

Bee pollen continues to increase its popularity as a ‘complete food’ among natural resources with its high health value and therapeutic chemical compounds. This study focused on HPLC-DAD (high-performance liquid chromatography-diode array detection) based on the identification of chemical compounds of Cistus creticus, Helianthus annuus, Papaver somniferum and Salix sp. bee pollens. Also, water extracts and the fractions (hexane, dichloromethane, ethyl acetate, butanol, water) obtained from the methanol extracts of all bee pollens were investigated for chemical compounds. A total of 29 chemical compounds were screened and kaempferol was detected in all studied bee pollen samples at concentration of 0.4 and 331.6 µg/g. Luteolin (68.7–694.8 µg/g), trans-aconitic acid (12.2–479.1 µg/g), myricetin (160.4–1534.2 µg/g), quercetin (162.1–608.1 µg/g), rosmarinic acid (273.8–435.6 µg/g), rutin (3.6–202.8 µg/g), and trans-cinnamic acid (5.1–1854.6 µg/g) were found as the most abundant chemical compounds. Additionally, nonpolar and polar fractions of the bee pollens were chemometrically clustered for similarities and differences of chemical compounds via principal component analysis (PCA) and hierarchical cluster analysis (HCA). In nonpolar fractions, C. creticus, H. annuus, P. somniferum, and Salix sp. ethyl acetate fractions (CEA, HEA, PEA, SEA) were separated from other fractions, while in polar fractions, C. creticus, H. annuus, P. somniferum, and Salix sp. butanol fractions (CB, HB, PB, SB) were separated from other fractions. This study provides additional data on the characterization of valuable chemical compounds in bee pollens and constitutes a beginning in the chemometric classification of chemical compounds.