Portuguese propolis disturbs glycolytic metabolism of human colorectal cancer in vitro

Propolis is a resin collected by bees from plant buds and exudates, which is further processed through the activity of bee enzymes. Propolis has been shown to possess many biological and pharmacological properties, such as antimicrobial, antioxidant, immunostimulant and antitumor activities. Due to this bioactivity profile, this resin can become an alternative, economic and safe source of natural bioactive compounds.Antitumor action has been reported in vitro and in vivo for propolis extracts or its isolated compounds; however, Portuguese propolis has been little explored. The aim of this work was to evaluate the in vitro antitumor activity of Portuguese propolis on the human colon carcinoma cell line HCT-15, assessing the effect of different fractions (hexane, chloroform and ethanol residual) of a propolis ethanol extract on cell viability, proliferation, metabolism and death. METHODS: Propolis from Angra do Heroísmo (Azores) was extracted with ethanol and sequentially fractionated in solvents with increasing polarity, n-hexane and chloroform. To assess cell viability, cell proliferation and cell death, Sulforhodamine B, BrDU incorporation assay and Anexin V/Propidium iodide were used, respectively. Glycolytic metabolism was estimated using specific kits. RESULTS: All propolis samples exhibited a cytotoxic effect against tumor cells, in a dose- and time-dependent way. Chloroform fraction, the most enriched in phenolic compounds, appears to be the most active, both in terms of inhibition of viability and cell death. Data also show that this cytotoxicity involves disturbance in tumor cell glycolytic metabolism, seen by a decrease in glucose consumption and lactate production. CONCLUSION: Our results show that Portuguese propolis from Angra do Heroísmo (Azores) can be a potential therapeutic agent against human colorectal cancer.We thank the Portuguese Science and Technology Foundation (FCT) for VMG fellowship (ref. SFRH/BI/33503/2008). The authors thank Mr. Antonio Marques from Frutercoop - Azores, who kindly collected and provided the propolis sample for the study

In vivo sexual discrimination in Salamandrina perspicillata: a cros-check analysis of annual changes in external cloacal morphology and spermic urine release

In Salamandrina, the lack of visible external sexual dimorphism makes the sexing of individuals difficult without sacrifice. The cloaca of Salamandrina in both males and females appears externally as a slit on an unswollen surface, a trait which is consistent throughout the year. Nonetheless, a slight divarication of its borders allows the recognition of three morphs (A, B and C), respectively characterizing male cloaca (all phases), female cloaca without protruding oviductal papillae (courtship phase) and female cloaca with prolapsed oviductal papillae (oviposition phase). Figures and schematic diagrams are provided to illustrate the differences in detail, which are all recognizable to the naked eye or by means of a hand magnifier. In addition to morphology, another reliable method of sexing salamanders is urine examination, albeit only during the courtship and post-courtship phases. Applying these methods for sex determination, we found a malebiased operational sex ratio in two populations, ranging from 6.6:1 (autumn–winter) to 14:1 (May). Males were confined to terrestrial environments, whereas females were also found in water during oviposition. Salamandrina perspicillata was active throughout the year, except during the hottest months (July–August)

Antioxidant activities of honeybee products and their mixtures

In this study, the total phenolic content (TPC), antioxidant activity, and free radical scavenging activities (FRSA) of 70 samples comprising honeybee products (honey, pollen, royal jelly, and propolis) and their mixtures were determined. The TPC was determined in accordance with the Folin-Ciocalteu method, antioxidant activity with phosphomolybdenum, and FRSA with the 1,1-diphenyl-2-picryl hydrazyl (DPPH) assays. Honeybee propolis showed the greatest TPC, antioxidant activity, and FRSA followed by pollen, honey, and royal jelly, respectively. A positive correlation was observed between TPC and antioxidant activity of honey, pollen and mixed samples (respectively, r=0.91, r=0.93 and r=0.92) (p < 0.01). Similarly, honey and mixed samples exhibited positive correlations with TPC and FRSA (respectively, r=0.98 and r=0.92) (p < 0.01). It was concluded that honeybee products and their mixtures have antioxidant activity and FRSA and these effects may be attributed to their phenolic content