Selective treatment to reduce contamination of propolis by polycyclic aromatic hydrocarbons (PAHs) still preserving its active polyphenol component and antioxidant activity

The adverse effects on health and environment caused by polycyclic aromatic hydrocarbons (PAHs) are critical problems. EFSA has defined 16 priority PAHs that are both genotoxic and carcinogenic, and identified eight (PAH8) priority PAHs as good indicators of the toxicity and occurrence in food. Food supplements containing propolis were also found to contain relatively high quantities of PAHs. We report about an extractive procedure which is able to purify propolis from a high content of PAHs using a balanced mixture of ethanol and water solvents. Extracts were characterised for total content of polyphenols, for in vitro antioxidant activity, and single classes of polyphenols evaluated by HPLC-ESI-MS. Obtained propolis extracts were found to have PAH8 and specific benzo[a]pyrene content below limits recommended by EFSA. The reported extractive procedure is easily applicable for possible industrial productions and may also be adopted to the purification of polyphenols from other plant extracts and natural sources.