Active Antioxidant Phenolics from Brazilian Red Propolis: An Optimization Study for Their Recovery and Identification by LC-ESI-QTOF-MS/MS

Brazilian red propolis (BRP) is a natural product widely known for its phenolic composition and strong antioxidant properties. In this study, we used the Box-Behnken Design (BBD) with Surface Response Methodology to optimize the extraction conditions for total phenolic content (TPC) and Trolox equivalent antioxidant capacity(TEAC) of bioactive phenolics from BRP. The extraction time, ethanol/water concentration and temperature, were tested. All variables had significant effects (p <= 0.05), with a desirability coefficient of 0.88. Under optimized conditions (90% ethanol at 80 degrees C for 30 min), the BRP extract showed a TPC of 129.00 +/- 2.16 mg GAE/g and a TEAC of 3471.76 +/- 53.86 mu mol TE/g. Moreover, FRAP and ORAC assays revealed that the optimized BRP extract had 1472.86 +/- 72.37 mu mol Fe2+/g and 4339.61 +/- 114.65 mu mol TE/gof dry weight, respectively. Thirty-two phenolic compounds were tentatively identified by LC-QTOF-ESI-MS/MS, of which thirteen were found for the first time in BRP, including four flavones, one flavanol, two flavanones, two chalcones, and four isoflavonoids. Thus, our results highlight the importance of BRP as a source of a wide variety of phenolic compounds with significant antioxidant properties.

Automated summary

The study optimized the extraction conditions for bioactive phenolics from BRP using Box-Behnken Design and Surface Response Methodology, resulting in BRP extract with significant antioxidant properties and a wide variety of phenolic compounds.