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

Ethyl 3-methyl-1-oxo-4H-1,4-benzothiazine-2-carboxylate

The crystal structure of the title compound, C12H13NO3S, is stabilized by intermolecular N - H (. . .) O hydrogen bonds, which are formed between the NH groups and the sulfoxide O atoms

Crystal structure and Hirshfeld surface analysis of (2E)-3-(4-chloro-3-fluorophenyl)-1-(3,4-dimethoxyphenyl)prop-2-en-1-one

The molecular structure of the title compound, C17H14ClFO3, consists of a 4-chloro-3-fluorophenyl ring and a 3,4-dimethoxyphenyl ring linked via a prop-2-en-1-one spacer. The molecule has an E configuration about the C=C bond and the carbonyl group is syn with respect to the C=C bond. The Fand H atoms at the meta positions of the 4-chloro-3-fluorophenyl ring are disordered over two orientations, with an occupancy ratio of 0.785 (3):0.215 (3). In the crystal, molecules are linked via pairs of C-H center dot center dot center dot O interactions with an R-2(2)(14) ring motif, forming inversion dimers. The dimers are linked into a tape structure running along [10 (1) over bar] by a C-H center dot center dot center dot pi interaction. The intermolecular contacts in the crystal were further analysed using Hirshfield surface analysis, which indicates that the most significant contacts are H center dot center dot center dot H (25.0%), followed by C center dot center dot center dot H/H center dot center dot center dot C (20.6%), O center dot center dot center dot H/H center dot center dot center dot O (15.6%), Cl center dot center dot center dot H/H center dot center dot center dot Cl (10.7%), F center dot center dot center dot H/H center dot center dot center dot F (10.4%), F center dot center dot center dot C/C center dot center dot center dot F (7.2%) and C center dot center dot center dot C (3.0%)