Comparison of genotoxicity potentials between crude Thai bee pollen and its extracts

Bee pollen is traditionally used as a food supplement and a natural medicine [1]. However, its genotoxicity and cytotoxicity studies are limited. This study investigated the genotoxicity and cytotoxicity of commercial crude bee pollen (CBP) from Northern Thailand using in vitro sister chromatid exchange (SCE) assay in human lymphocytes. The lipid fractions (LF) and defatted fractions (DF) obtained from CBP-Soxhlet extraction using diethyl ether, were also analysed. Human lymphocytes were treated with CBP at 5, 50, 500, and 5000 ng/ml, LF at 1.25, 12.5, 125 and 1250 ng/ml and DF at 5, 50, 500, and 5000 ng/ml for three hours and were then harvested, stained and scored for SCE. RPMI culture medium and doxorubicin were used as negative and positive controls, respectively. Results revealed that only CBP at 5000 ng/ml was cytotoxic to human cells as few mitotic cells were detected. SCE levels were significantly increased in human lymphocytes treated with 5 and 500 ng/ml CBP compared to the negative control (p < 0.05), indicating that the genetic damage was induced in these CBP groups. Treatment with LF at 1.25 ng/ml significantly increased SCE levels, but this genotoxicity was not observed in the higher concentrations. Treatment with DF at all concentrations significantly induced genetic damage. Chemical composition analyses revealed that flavonoid and phenolic acid contents were 2.5- and 8-fold higher in DF than in LF, respectively. Interestingly, LF contained 14 times higher amounts of ferulic acid than DF did. Moreover, vitamin E was only detected in LF. In summary, DF at all doses induced significant genotoxicity while CBP at 5 and 500 ng/ml as well as LF only at 1.25 ng/ml induced significant genetic damage. The underlying mechanisms may involve their different composition ratio such as ferulic acid, and vitamin E. Further studies of these molecular mechanisms underlying genotoxicity should be encouraged.

Acknowledgements: This work is supported by Research Fund, Thammasat University 2015 and Research Fund, National Research University Project of Thailand. Office of Higher Education Commission and Thammasat University, Thailand.

Keywords: Bee pollen, sister chromatid exchange, genotoxicity, ferulic acid, human lymphocyte.

References:

[1] Komosinska-Vassev K, Olczyk P, Kazmierczak J, Mencner L, Olczyk K. Bee pollen: chemical composition and therapeutic application. Evid Based Complement Alternat Med 2015; 297425

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