Chemometric Tools to Characterize Phenolic Compounds with Antioxidant Activity of Melipona quadrifasciata Propolis from Brazil

Propolis is an apicultural product whose composition depends on the climate conditions, geographical region, source of the resinous substance, and bee species. It is rich in phenolic compounds with antioxidant potential. This study aimed to establish better extraction conditions of bioactive compounds from Melipona quadrifasciata (MQ) propolis using a central composite rotational design (CCRD) and multivariate statistical tools. The solvent concentration and extraction time effects on the phenolic compounds profile with antioxidant activity (AA) were evaluated. The total phenolic compounds (TPC) and AA varied from 20.43 to 56.03 mg GAE g(-1) (gallic acid equivalent) and 95.89 to 154.67 mmol Trolox g(-1), respectively. The best condition for TPC and AA was 50% ethanol and 60 min of the extraction. However, each phenolic compound identified had a different best extraction condition, probably due to the molecules' polarity and solvent interaction. The cinnamic acid was the highest content identified, followed by ferulic acid, gallic acid, epicatechin, p-coumaric acid, and catechin. Anyway, more extended times of extraction and solvent concentration closer to 50% ethanol can maximise the extraction of compounds with antioxidant potential. Thus, the Brazilian stingless bee propolis could be considered a potential source of bioactive compounds with potent antioxidant capacity, which could be further explored for future applications as natural antioxidants in several products.