Email updates

Keep up to date with the latest news and content from BMC Complementary and Alternative Medicine and BioMed Central.

Open Access Research article

Portuguese propolis disturbs glycolytic metabolism of human colorectal cancer in vitro

Isabel Valença123, Filipa Morais-Santos12, Vera Miranda-Gonçalves12, Ana Margarida Ferreira4, Cristina Almeida-Aguiar3 and Fátima Baltazar12*

Author Affiliations

1 Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho, Braga, Portugal

2 ICVS/3B’s - PT Government Associate Laboratory, Braga/Guimarães, Portugal

3 CBMA - Centre of Molecular and Environmental Biology, Biology Department, University of Minho, Braga, Portugal

4 Chemistry Centre Vila Real (CQVR), University of Trás-os-Montes e Alto Douro, Vila Real, Portugal

For all author emails, please log on.

BMC Complementary and Alternative Medicine 2013, 13:184  doi:10.1186/1472-6882-13-184

Published: 19 July 2013

Abstract

Background

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.

Keywords:
Antitumor activity; Colorectal cancer; Glycolytic metabolism; HCT-15 cells; Propolis