Isolation of polyphenols with anticancer activity from the Baltic Sea brown seaweed Fucus vesiculosus using bioassay-guided fractionation

Brown seaweeds have been used in phytotherapy since ancient times. A multitude of medical effects have been reported for their ingredients which also cover anticancer activities. Though being the most common brown seaweed in the Baltic Sea, nothing is known-apart from our recent publication (Geisen et al. Mar Drugs 13:4470-4491, 2015)-about the anticancer potential of the Bladderwrack, Fucus vesiculosus L., grown in this particular habitat with low salinity and nontidal shores. The aim of the present study was to investigate systematically the alga's cytotoxic potential against human pancreatic cancer cells and to develop a purification procedure for the active compounds by using a bioassay-guided fractionation approach. Four out of six crude extracts showed considerable cytotoxic activity against Panc89 cells, three of which were considerably active against PancTU1 cells, as well. The most active crude extract revealed an effective half maximal concentration (EC50) of 72 mu g mL(-1) against Panc89 and of 77 mu g mL(-1) against PancTU1 cells after 72 h of treatment. The multistep purification procedure established for this extract resulted in a fourfold reduction of the EC50. Monitoring of each crude extract and fraction via H-1-NMR spectroscopy revealed a characteristic fingerprint which was significantly correlated with the activity. Structural analysis of the most active fractions revealed two similar molecules belonging to the group of polyphenols. Further separation is needed to present the chemical structure in all molecular details. The results show that F. vesiculosus from the Baltic Sea holds potent and novel anticancer substances.