In vitro chemopreventive potential of fucophlorethols from the brown alga Fucus vesiculosus L. by anti-oxidant activity and inhibition of selected cytochrome P450 enzymes.

Within a project focusing on the chemopreventive potential of algal phenols, two phloroglucinol derivatives, belonging to the class of fucophlorethols, and the known fucotriphlorethol A were obtained from the ethanolic extract of the brown alga Fucus vesiculosus L. The compounds trifucodiphlorethol A and trifucotriphlorethol A are composed of six and seven units of phloroglucinol, respectively. The compounds were examined for their cancer chemopreventive potential, in comparison with the monomer phloroglucinol.

Evaluation of quantitative methods for the determination of polyphenols in algal extracts.

Marine brown algae such as Ascophyllum nodosum and Fucus vesiculosus accumulate polyphenols composed of phloroglucinol units. These compounds are of ecological importance and, due to their antioxidative activity, of pharmacological value as well. In this study four methods for the quantitative determination of phlorotannins are compared: spectrophotometric determinations using Folin-Ciocalteu's phenol reagent or 2,4-dimethoxybenzaldehyde (DMBA), quantitative (1)H NMR spectroscopy (qHNMR), and gravimetrical measurements.

Nonhalogenated and halogenated phlorotannins from the brown alga carpophyllum angustifolium.

Using HPLC, forty-five phloroglucinol derivatives were obtained from an ethanolic extract of the brown alga Carpophyllum angustifolium after peracetylation. Compounds of the fuhalol-B series are described. The structure of hydroxyheptafuhalol-B nonadecaacetate is confirmed by the addition of (13)C NMR spectral data, octafuhalol-C heneicosaacetate is described for the first time.

Halogenated phlorethols and fucophlorethols from the brown alga Cystophora retroflexa.

From an ethyl acetate fraction of the brown alga Cystophora retroflexa several halogenated phlorotannins were isolated. Most of the compounds are derivatives of diphlorethol penta-acetate and triphlorethol-A hepta-acetate. The majority turned out to be chlorinated and/or brominated.