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Isolation and identification of compounds with antioxidant activity in a novel variety of Brazilian propolis produced by bees from the species Apis mellifera Propolis is known for its wide range of biological activities, such as antioxidant, antibacterial, anti-inflammatory, antiviral, among others. Its composition varies according to the region where it is collected and there is a great chemical diversity among the different types of propolis. The main constituents of propolis are the phenolic compounds, which are responsible for several biological activities, such as the antioxidant activity. A novel type of propolis, which has never been reported in the literature before, named red propolis due to its intense characteristic color, was collected in a mangrove area in the state of Alagoas. This study aimed to evaluate the chemical composition, and fractionate and isolate the compounds with antioxidant activity of Brazilian red propolis. The Ethanolic Extract of Propolis (EEP) was first fractionated using the liquid-liquid extraction technique, yielding the hexanic (Hex-fr) and the chloroformic fractions (Chlo-fr). Chlo-fr showed great yield and a complex chemical composition and therefore was refractioned in silica gel open column, yielding 15 subfractions. The EEP, fractions and subfractions were evaluated for their chemical composition and antioxidant activity aiming to select the fractions destined for bioguided isolation. The EEP was also analyzed by the gas-chromatography-mass spectrometry (GC-MS) technique, and seven compounds, never reported for Brazilian propolis before, were identified, among which are four isoflavonoids. The amounts of total polyphenol and flavonoid compounds, tested for EEP, fractions and subfractions, ranged from 37,4 to 324,2 mg/g and 0,0 to 158 mg/g, respectively. The major free radical (DPPH) scavenging activity was found for Hex-fr, while subfraction 5 showed high yield and good antioxidant activity by β-carotene/linoleic acid system oxidation, and these fractions were selected for isolation of bioactive compounds by preparative High Performance Liquid Chromatography (HPLC). Three compounds, one from Hex-fr and two from subfraction 5, were isolated and analyzed by GC-MS. The compounds from subfraction 5 were identified as 2,7-diidroxi4metoxiisoflavan (vestitol) and 2,4-dihidroxi-7 metoxiisoflavan, both isoflavonoids. It was not possible to identify the compound from Hex-fr using GC-MS, although it was possible to verify that this compound is a mixture of two isomers presenting molecular weight of 466 g/mol. The results obtained in this study demonstrate that red propolis is a good source of bioactive compounds, among which are isoflavonoids, compounds that possess antioxidant activity.

Isolamento e identificação de compostos com atividade antioxidante de uma nova variedade de própolis brasileira produzida por abelhas da espécie Apis mellifera