Tatiane Luiza C. Oldonia, Ingridy S.R. Cabrala, Marisa A.B. Regitano d’Arcea, Pedro L. Rosalenb, Masaharu Ikegakic, Andrea M. Nascimentoa, Severino M. Alencara,∗
a Department of Agri-Food Industry, Food and Nutrition, “Luiz de Queiroz” College of Agriculture, University of Sao Paulo (USP), P.O. Box. 9, 13418-900, Piracicaba, SP, Brazil b Department of Physiological Sciences, Piracicaba Dental School, University of Campinas (UNICAMP), P.O. Box 52, 13414-903, Piracicaba, SP, Brazil
c Faculty of Pharmaceutical Sciences, Federal University of Alfenas, Av. Gabriel Monteiro da Silva, 700, 37130-000, Alfenas, MG, Brazil
Activity-directed fractionation and purification processes were employed to identify isoflavonoids with antioxidant and antimicrobial activities from Brazilian red propolis. Crude propolis was extracted with ethanol (80%, v/v) and fractioned by liquid–liquid extraction technique using hexane and chloroform. Since chloroform fraction showed strong antioxidant and antimicrobial activities it was purified and isolated using various chromatographic techniques. Comparing our spectral data (UV, NMR, and mass spectrometry) with values found in the literature, we identified two bioactive isoflavonoids (vestitol and neovestitol), together with one chalcone (isoliquiritigenin). Vestitol presented higher antioxidant activity against β-carotene consumption than neovestitol. The antimicrobial activity of these three compounds against Staphylococcus aureus, Streptococcus mutans, and Actinomyces naeslundii was evaluated and we concluded that isoliquiritigenin was the most active one with lower MIC, ranging from 15.6 to 62.5 μg/mL. Our results showed that Brazilian red propolis has biologically active isoflavonoids that may be used as a mild antioxidant and antimicrobial for food preservation.
* THESE STATEMENTS HAVE NOT BEEN EVALUATED BY THE FOOD AND DRUG ADMINISTRATION. THIS IS NOT INTENDED TO DIAGNOSE, TREAT CURE OR PREVENT ANY DISEASE.