Karl-Werner Glombitza

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. Trifucodiphlorethol A, trifucotriphlorethol A as well as fucotriphlorethol A were identified as strong radical scavengers, with IC(50) values for scavenging of 1,1-diphenyl-2 picrylhydrazyl radicals (DPPH) in the range of 10.0-14.4 microg/ml. All three compounds potently scavenged peroxyl radicals in the oxygen radical absorbance capacity (ORAC) assay. In addition, the compounds were shown to inhibit cytochrome P450 1A activity with IC(50) values in the range of 17.9-33 microg/ml, and aromatase (Cyp19) activity with IC(50) values in the range of 1.2-5.6 microg/ml.

Phlorotannins with dibenzodioxin structural elements from the brown alga Eisenia arborea

Abstract Twenty-one polyhydroxyphenols, which can all be derived from phloroglucinol, were isolated from Canadian Eisenia arborea (Alariaceae). Most of these compounds contain dibenzo[1,4]dioxin elements and also others benzofuran moieties. The basic component is eckol, a hexahydroxyphenoxydibenzo[1,4]dioxin consisting of three phloroglucinol units. Dioxinodehydroeckol is a benzo[1′,4′]benzodioxino[1,4]benzodioxin derived from eckol. 7,7′-Bieckol, 7,9′-bieckol and 7,2″-bieckol are dimers of eckol with biaryl linkages. 8,4·-Dieckol is a dimeric diphenyl ether. 7-Hydroxyeckol contains one and 7,7′-dihydroxy-9,9′-bieckol two additional hydroxyl groups. 3-Phloroeckol and the dehydro derivatives furodehydroeckol A,B and C are composed of four phloroglucinol rings. Halogenated compounds also occur: monobromo- and monoiodophloroglucinol, 4′-bromo- and 4′-iodoeckol as well as one bromo- and one iodophloroeckol.

Bifuhalol und diphlorethol aus Cystoseira tamariscifolia

Abstract From an acetylated fraction of the extract of Cystoseira tamariscifolia two phenol acetates could be isolated and their structure established as: 2,4,6,3′,5′-pentaacetoxydiphenyl ether (1, diphlorethol pentaacetate) and 3,4,5,2′,4′,6′-hexaacetoxydiphenyl ether (2, bifuhalol hexaacetate).

Fucole, polyhydroxyoligophenyle aus Fucus vesiculosus

Abstract From the fraction of acetylated phenols of Fucus vesiculosus were isolated: phloroglucinol triacetate, difucol hexaacetate (2,2′,4,4′,6,6′-hexaacetoxydiphenyl), trifucol nonaacetate [1,5-di (2,4,6-triacetoxyphenyl)-2,4,6-triacetoxybenzene] and a mixture of two isomeric tetrafucol dodecaacetates A and B.

Der Tryptophanabbau bei Endomycopsis Vernalis und Anderen Hefen

Summary1.The degradation of tryptophan (Try) and some of its potential intermediates has been studied in Endomycopsis vernalis. The following degradation products were identified in surface-cultures of Endomycopsis which had been fed with C-14-labeled d,l-Try for 12–24 hrs: β-(indolyl-3)-pyruvic acid (IBS); β-(indolyl-3-)lactic acid (IMS); α-(indolyl-3-)acetic acid (IES); indolyl-3-carboxylic acid (ICS); β-(indolyl-3-)ethanol (β-IÄ); indole-3-aldehyde (IAld); Nα-acetyl-tryptophan (Ac-Try). Indole-3-acetaldehyde (IAAld) could be demonstrated only in experiments in which cell-free extracts were used.2.IMS was isolated from the culture medium and was identified by means of chemical methods and IR- and mass-spectra. Feeding of both d- and l-Try yielded L-(-)-indolyllactic acid exclusively.3.The first step in the breakdown of Try has been shown to be a transamination-reaction leading to the formation of IBS. The NH2-group can be transferred to α-ketoglutaric acid as well as to phenylpyruvic acid.4.The degradation products of Try were determined quantitatively by feeding C-14-(3-alanyl-)d,l-Try to Endomycopsis cultures. After 10 hrs nearly 60% of the original radioactivity of Try was found in IMS. In comparison to IMS the concentrations of the other degradation products formed were rather small: Ac-Try (about 1/7 of the IMS-concentration), IES (1/10), β-IÄ (1/12), ICS (1/80), IAld (1/220).5.The following pathways in the degradation of Try in Endomycopsis vernalis are assumed to be of physiological, i.e., enzymatic, nature: Try→IBS→IAAld→β-IÄ, and Try→Ac-Try, and IBS→IMS. IMS and β-IÄ appear to be metabolic end products.Zusammenfassung1.Nach Verfütterung von d,l-Tryptophan (d,l-Try) und anderen Indolkörpern an Oberflächenkulturen von Endomycopsis vernalis konnten folgende Abbauprodukte nachgewiesen werden: Nα-Acetyl-tryptophan (Ac-Try), β-(Indolyl-3-)brenztraubensäure (IBS), β-(Indolyl-3-) milchsäure (IMS), α-(Indolyl-3-)essigsäure (IES), Indol-3-carbonsäure (ICS), β-(Indolyl-3-)äthanol (β-IÄ), Indol-3-aldehyd (IAld). Der Nachweis von Indolyl-3-acetaldehyd (IAAld) gelang nur in Versuchen mit zellfreien Extrakten.2.IMS wurde präparativ isoliert und mit Hilfe chemischer und physikalischer Methoden identifiziert. Sowohl die Verfütterung von d- als auch von l-Try lieferten ausschließlich l-(-)-Indolylmilchsäure.3.Der erste Schritt im Try-Abban ist eine Transaminierung, die zur Bildung von IBS führt. Die NH2-Gruppe kann sowohl auf α-Ketoglutarsäure als auch auf Phenylbrenztraubensäure übertragen werden.4.Eine quantitative Bestimmung der Try-Abbauprodukte mit Hilfe von 14C(3-Alanyl)-d,l-Try ergab, daß der überwiegende Teil des Try zu IMS abgebaut wird. Es folgen in abnehmendem Mengenverhältnis: Ac-Try, IES, β-IÄ, ICS, IAld.5.Auf Grund der Ergebnisse wird angenommen, daß folgende Reaktionen im Try-Abbau bei Endomycopsis physiologisch, d.h. enzymatisch bedingt sind: Try→IBS→IAAld→β-IÄ sowie Try→Ac-Try und IBS→IMS.1. The degradation of tryptophan (Try) and some of its potential intermediates has been studied in Endomycopsis vernalis. The following degradation products were identified in surface-cultures of Endomycopsis which had been fed with C-14-labeled D,L-Try for 12-24 hrs: β-(indolyl-3)-pyruvic acid (IBS); β-(indolyl-3-)lactic acid (IMS); α-(indolyl-3-)acetic acid (IES); indolyl-3-carboxylic acid (ICS); β-(indolyl-3-)ethanol (β-IÄ); indole-3-aldehyde (IAld); Nα-acetyl-tryptophan (Ac-Try). Indole-3-acetaldehyde (IAAld) could be demonstrated only in experiments in which cell-free extracts were used. 2. IMS was isolated from the culture medium and was identified by means of chemical methods and IR- and mass-spectra. Feeding of both D- and L-Try yielded L-(-)-indolyllactic acid exclusively. 3. The first step in the breakdown of Try has been shown to be a transamination-reaction leading to the formation of IBS. The NH2-group can be transferred to α-ketoglutaric acid as well as to phenylpyruvic acid. 4. The degradation products of Try were determined quantitatively by feeding C-14-(3-alanyl-) D,L-Try to Endomycopsis cultures. After 10 hrs nearly 60% of the original radioactivity of Try was found in IMS. In comparison to IMS the concentrations of the other degradation products formed were rather small: Ac-Try (about 1/7 of the IMS-concentration), IES (1/10), β-IÄ (1/12), ICS (1/80), IAld (1/220). 5. The following pathways in the degradation of Try in Endomycopsis vernalis are assumed to be of physiological, i.e., enzymatic, nature: Try→IBS→IAAld→β-IÄ, and Try→Ac-Try, and IBS→IMS. IMS and β-IÄ appear to be metabolic end products.

Polyhydroxyoligophenyle und phenyläther aus Bifurcaria bifurcata

Abstract From the acetylated phenol fraction of Bifurcaria bifurcata were isolated: diphlorethol pentaacetate, difucol hexaacetate, trifuhalol octaacetate, trifucol nonaacetate, heptafuhalol octadecaacetate and the new tetrafuhalol undecaacetate and pentafuhalol tridecaacetate.

Bifuhalol: Ein diphenyläther aus Bifurcaria bifurcata☆

Abstract The structure of bifuhalol, a polyhydroxyphenyl ether isolated from Bifurcaria bifurcata Ross has been established from the peracetyl derivativ

Fuhalols and deshydroxyfuhalols from the brown alga sargassum spinuligerum

Abstract Using a highly sophisticated HPLC method, 20 fuhalols and deshydroxyfuhalols were isolated from the ethanolic extract of the brown alga Sargassum spinuligerum. Because of their instability they were peracetylated before isolation. In addition to well known phlorotannins like deshydroxytetrafuhalol-A, tetrafuhalol-A, pentafuhalol-A, hexafuhalol-A, heptafuhalol-A, octafuhalol-A, nonafuhalol-A and undecafuhalol-A, the acetylated derivatives of deshydroxytetrafuhalol-C, deshydroxyhexafuhalol-A,-C and -D, deshydroxyoctafuhalol-C, octafuhalol-B, decafuhalol-A, dodecafuhalol-A, tetradecafuhalol-A, hexadecafuhalol-A, octadecafuhalol-A and eicosafuhalol-A are described for the first time. The last of them, containing twenty phloroglucinol units, is the largest phlorotannin isolated in purified form to date. The structural elucidation was carried out on the basis of 1H, 13C NMR and mass spectral data.

Fucols and Phlorethols from the Brown Alga Scytothamnus australis Hook. et Harv.(Chnoosporaceae)

Abstract Eight fucols and two phlorethols were isolated by HPLC from the ethanolic extract of the brown alga Scytothamnus australis,. Because of their instability the substances were peracetylated before isolation. The phlorotannins trifucolnonaacetate, tetrafucol-A-dodecaacetate, tetrafucol-B-dodecaacetate, cis-pentafucol-A-pentadecaacetate, diphlorethol-A-pentaacetate and triphlorethol-A-heptaacetate have been characterized previously. In addition to these substances we found hydroxytetrafucol-B-tridecaacetate, pentafucol-B-pentadecaacetate, cis, trans-pentafucol-A-pentadecaacetate and hexafucol-B-octadecaacetate all of which are described for the first time. The elucidation of their structure was achieved by 1H NMR, 13C NMR, 1H 1H ROESY NMR and mass spectral data.

Der Tryptophanabbau bei Rhizobium leguminosarum

SummaryThe degradation of tryptophan (Try) and some of its potential intermediates has been studied in nodule bacteria (Rhizobium leguminosarum Frank, ATCC 10324). In feeding experiments with washed suspensions the following degradation products of Try could be identified by thin-layer chromatography: indolyl-3-pyruvic acid (IBS); indolyl-3-acetic acid (IES); β-(indolyl-3)-lactic acid (IMS); indole-carboxylic acid-(3) (ICS); β-(indolyl-3)-ethanol (β-IÄ); indole-aldehyde-(3) (IAld); indolyl-3-acetaldehyde (IAAld); Nα-acetyl-tryptophan (Ac-Try).An active Try-transaminase leading to the formation of IBS has been demonstrated. Phenylpyruvic acid as well as α-ketoglutaric acid served as amino group acceptors.The breakdown of Try was followed quantitatively by using C-14(2-alanyl-)D,L-tryptophan. After 16 hrs nearly 16% of the original radioactivity was found in the ether-extractable material. IES and IMS were formed in much the highest concentrations.Indole-3-acetonitrile (IAN), although not a Try-metabolite in Rhizobium leguminosarum was converted to IES via indole-3-acetamide (IAAm). The following physiological pathways in the breakdown of Try in Rhizobium leguminosarum have been confirmed: Try → Ac-Try and IBS; IBS → IAAld; IAAld → β-IÄ and IES; no further degradation of IES was observed.