Flavonoids, bioactive components of propolis, exhibit cytotoxic activity and induce cell cycle arrest and apoptosis in human breast cancer cells MDA-MB-231 and MCF-7 : A comparative study

Breast cancer is one of the most common causes of mortality in women. Flavonoids, among other compounds, are bioactive constituents of propolis. In this comparative study, we investigated the effects of flavonoids apigenin (API), genistein (GEN), hesperidin (HES), naringin (NAR) and quercetin (QUE) on the proliferation, apoptosis, and cell cycle of two different human cancer cells - MDA-MB-231, estrogen-negative, and MCF-7, estrogen-positive receptor breast carcinoma cells. Many cytotoxic reports of flavonoids were performed by MTT assay. However, it's reported that MTT is reduced in metabolically active cells and yields an insoluble purple formazan, which indicates that obtained cytotoxic results of flavonoids could be inconsistent. Cell viability was measured by NR, neutral red assay, while the percentage of apoptotic cells and cell cycle arrest were determined by flow cytometry and Muse cell cycle assay, respectively. The results showed a high dose-dependent effect in cell viability tests. IC50 values were as follows (MCF-7/MDA-MB-231, for 48 h, in \u3bcM): 9.39/50.83 for HES, 25.19/88.17 for API, 40.26/333.51 for NAR, 49.49/47.50 for GEN and 95.12/130.10 for QUE. Flavonoid-induced apoptosis was dose- and time-dependent, for both cancer cell lines, though flavonoids were more active on MCF-7 cells. The flavonoids also induced cell cycle arrest in cancer cells

Long-term microbiological and chemical changes in bee pollen for human consumption: influence of time and storage conditions

In order to evaluate if bee pollen properly processed could be conserved for more than 12 months without suffering alterations on its microbiological and chemical qualities, 48 dried bee pollen samples from Argentina were stored at room (23 ± 2 °C) and at refrigerated temperatures (4 °C) during two years. The microbiological (culturable heterotrophic mesophilic bacteria, yeasts and filamentous fungi, Enterobacteriaceae, coliforms, spore-forming bacteria, Salmonella sp., Escherichia coli, Staphylococcus aureus and Clostridium perfringens) and chemical qualities (moisture, pH, ash, proteins and carbohydrates) of three samples from each treatment were evaluated every three months over two years. In bee pollen samples, human pathogenic bacteria were not detected. In general, the count of yeasts, culturable heterotrophic mesophilic bacteria and filamentous fungi were statistically lower at room temperature compared to refrigerated temperature over the storage period. Aerobic spore-forming bacteria populations did not show significant changes at the different storage periods neither at room nor at refrigerated temperatures. The protein and the ash content did not differ while carbohydrate content, moisture and pH changed over the storage period. The results show that microorganisms do not multiply in dried bee pollen although they can be present after a long period of storage at both studied temperatures. Bee pollen has maintained its microbiological and chemical qualities for more than six months at both temperatures, however, at room temperature, its sensory properties were altered after nine months from the beginning of the storage. The shelf life could be longer if it was preserved at fridge temperature.Fil: Fernandez, Leticia Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca; Argentina. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; Argentina. Universidad Nacional del Sur. Departamento de Agronomía. Laboratorio de Estudios Apícolas; ArgentinaFil: Rodríguez, María Agustina. Universidad Nacional del Sur. Departamento de Agronomía. Laboratorio de Estudios Apícolas; ArgentinaFil: Sanchez, Romina Magali. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; ArgentinaFil: Perez, Monica Beatriz. Universidad Nacional del Sur. Departamento de Química; ArgentinaFil: Gallez, Liliana María. Universidad Nacional del Sur. Departamento de Agronomía. Laboratorio de Estudios Apícolas; Argentin