Effect of light, oxygen and temperature on the stability of artepillin C and p-coumaric acid from Brazilian green propolis.

Brazilian Green Propolis (BGP) is an important bee product, which displays important biological activities, making it valuable in the international market. The major prenylated phenolic compound in BPG is (E)-artepillin C, along with its precursor (E)-p-coumaric acid, both contributing to the biological effects of BGP. Taking that into account, it was evaluated the effect of light, temperature and air oxygen in their content to establish the best storage and transport conditions for crude BGP and the pure compounds. For that, (E)-artepillin C and (E)-p-coumaric acid were initially submitted to degradation for five days under sunlight and high temperature (50 °C), furnishing three major (E)-Artepillin C isomers and one from (E)-p-coumaric acid. Then, it was developed and validated a Reverse Phase High Performance Liquid Chromatography (RP-HPLC) method for quantifying these compounds in crude BGP and in its extracts. In the stability studies, it was used a Full Factorial and Central Composite Design to establish the desirable storage conditions. (E)-Artepillin C, both pure and in BGP should be kept protected from light and storage below -2.5 °C. (E)-p-Coumaric acid can be stored at room temperature. Therefore, the best storage and transport conditions to keep the content of both compounds in BGP are protection from light at low temperatures.