Isolation and Quantification of the Main Prenylated Compounds from Brazilian Green Propolis with Antioxidant Properties

Brazilian green propolis is produced by Apis mellifera L. in the Southeast region of the country. It is known for its wide spectrum of biological activities, such as antimicrobial, cytotoxic, and antioxidant. Brazilian green propolis is composed of prenylated cinnamic acids collected from Baccharis dracunculifolia DC, with Artepillin C serving as a biomarker for identification and quality control. This study aimed to identify and quantify the main prenylated substances found in hexane and ethanol extracts of Brazilian green propolis. Total phenolic and flavonoid contents were determined by colorimetric methods, and DPPH free radical scavenging was used to measure the antioxidative activities. Fractionation of crude hexane extract by flash chromatography led to a sub-fraction rich in prenylated substances, characterized by 1H and 13C NMR. Analytic HPLC-PDA was used to quantify prenylated substances in crude propolis extracts and the results were used to compare the antioxidant properties of each substance to crude extracts.