Armin Presser

Sesquiterpenes and flavonoid aglycones from a Hungarian taxon of the Achillea millefolium group.

The investigation of a dichloromethane extract of flower heads of a Hungarian taxon of the Achillea millefolium group led to the isolation of three flavonoid aglycones, one triterpene, one germacranolide and five guaianolides. Their structures were elucidated by UV-VIS, EI- and CI-MS, 1H NMR and 13C NMR spectroscopic methods as well as by 2D-NMR studies and by selective 1D-NOE experiments. Besides apigenin, luteolin and centaureidin, β-sitosterol, 3β-hydroxy-11α,13-dihydro-costunolide, desacetylmatricarin, leucodin, achillin, 8α-angeloxy-leucodin and 8α-angeloxy-achillin were isolated. Both latter substances are reported here for the first time. Their NMR data were compared with those of the other guaianolides. The stereochemistry of 3β-hydroxy-11α,13-dihydro-costunolide was discussed and compared with data of the literature.

In Vitro Anti-inflammatory Activity of Larch (Larix decidua L.) Sawdust

The influence of larch (Larix decidua L.) sawdust extracts on arachidonate metabolism has been evaluated in vitro. Extracts of different polarities were tested for their ability to inhibit prostaglandin formation by COX-1 and COX-2 and LTB(4) formation by 5-LOX. The lipophilic n-heptane extract showed the highest activity (IC(50) values: COX-1, 5 microg/mL; COX-2, 0.1 microg/mL; LTB(4) assay, 11.1 microg/mL). A series of abietane, pimarane, and labdane type diterpenes isolated from this extract turned out to be potent inhibitors of LTB(4) product formation, whereas their COX inhibitory activity was less pronounced. From the abietane type diterpenes, compounds possessing a 7,13-abietadiene skeleton were better inhibitors of LTB(4) formation than those with an 8,11,13-abietatriene skeleton. Compounds bearing an OH group in position 4 were more active than those substituted with a COOH group, and methylation of the COOH group led to an almost complete loss of LTB(4) formation inhibitory activity.

Influence of structure and chirality of the selector on the chiral recognition of amino acids using ligand-exchange capillary electrophoresis.

The dependence of the chiral recognition ability and enantiomer migration order on the structure, substitution pattern and chirality of chiral selectors used in ligand‐exchange capillary electrophoresis is investigated. As chiral selectors different N‐alkyl derivatives of proline and hydroxyproline as their copper(II) complexes are used. The influence of the position and conformation of the hydroxy group in the hydroxyproline derivatives and of the structure and chirality of the side chain on enantioselectivity is investigated. Furthermore, the effect of surfactants such as sodium dodecyl sulfate and cetyl trimethyl ammonium bromide on resolution and enantiomer migration order is studied. The investigations were carried out with three aromatic amino acids as model compounds.

Highly hydroxylated guaianolides of Achillea asiatica and Middle European Achillea species.

From flower heads of Achillea asiatica (L.) Serg., three new guaianolides were isolated by repeated column chromatography and HPLC. The constitution and the stereochemistry of these new, labile compounds were determined by MS, one ((1)H, (13)C, selective (1)H-TOCSY and (1)H-NOESY) and two-dimensional NMR experiments ((1)H, (1)H-COSY, (1)H, (13)C-HSQC, (1)H, (13)C-HMBC). The substances were identified as 8 alpha-angeloxy-2 alpha, 4 alpha,10 beta-trihydroxy-6 beta H,7 alpha H, 11 beta H-1(5)-guaien-12,6 alpha-olide (1), 8 alpha-angeloxy-1 beta,2 beta:4 beta,5 beta-diepoxy-10 beta-hydroxy-6 beta H, 7 alpha H, 11 beta H-12,6 alpha-guaianolide (2) and 8 alpha-angeloxy-4 alpha,10 beta-dihydroxy-2-oxo-6 beta H,7 alpha H, 11 beta H-1(5)-guaien-12,6 alpha-olide (3). They were also detected in Middle European species (Achillea collina, Achillea ceretanica (2x and 4x), Achillea roseoalba, Achillea asplenifolia) by HPLC, TLC and off line MS and have not been described before. The possibility that these compounds might be products of an oxidation process is discussed.

Flavonoid C- and O-glycosides from the Mongolian medicinal plant Dianthus versicolor Fisch.

Eighteen flavonoids were identified from an aqueous extract of the aerial parts of Dianthus versicolor, a plant used in traditional Mongolian medicine against liver diseases. The flavonoid C- and O-glycosides isoorientin-7-O-rutinoside, isoorientin-7-O-rhamnosyl-galactoside, isovitexin-7-O-rutinoside, isovitexin-7-O-rhamnosyl-galactoside, isoscoparin-7-O-rutinoside, isoscoparin-7-O-rhamnosyl-galactoside, isoscoparin-7-O-galactoside, and isoorientin-7-O-galactoside were isolated and structurally elucidated. Their structures were established on the basis of extensive spectroscopic techniques including LC-UV-DAD, LC-MS(n), LC-HRMS, 1D and 2D NMR spectroscopy, and by GC-MS analysis after hydrolysis. Flavonoids with such a high glycosylation pattern are rare within the genus Dianthus. Furthermore, isovitexin-7-O-glucoside (saponarin), isovitexin-2″-O-rhamnoside, apigenin-6-glucoside (isovitexin), luteolin-7-O-glucoside, apigenin-7-O-glucoside, as well as the aglycons luteolin, apigenin, chrysoeriol, diosmetin, and acacetin were identified by TLC and LC-DAD-MS(n) in comparison to reference substances or literature data. The NMR data of seven structures have not been reported in the literature to date.

Sesquiterpenes from Achillea pannonica Scheele

Abstract From dichloromethane extracts of flowerheads of Achillea pannonica Scheele three sesquiterpenes were isolated and identified: 11,13-dehydrodesacetylmatricarin, (6E)-5-tigloxy- 9-hydroxynerolidol and α-longipin-2-en-1-one. The structures were determined by MS, IR and NMR spectroscopic analyses. (6E)-5-Tigloxy-9-hydroxynerolidol is reported here for the first time. Additionally spathulenol, a compound of the essential oil was identified using GC-MS and GC-FTIR.

SYNTHESIS AND HAEMOLYTIC ACTIVITY OF RANDIANIN ISOMERS

Summary. Randianin, a haemolytic active saponin from Randia dumetorum, and some of its isomers with different carbohydrate side chains have been synthesized from oleanolic acid. The influence of the linkage within the disaccharide residue on the haemolytic activity of these glycosides has been investigated.Zusammenfassung. Randianin, ein hämolytisches Saponin aus Randia dumetorum, sowie einige dazu isomere Glycoside wurden ausgehend von Oleanolsäure synthetisiert. Der Einfluß der Verknüpfung in der Dissaccharidseitenkette auf die hämolytische Wirkung dieser Glycoside wurde untersucht.

Synthetic Transformations of Abietic Acid IV [1]. B- and C-Ring Oxidation

Summary. Selective oxidations at the B- or C-ring of abietic acid are described. The products can be used as educts for the synthesis of higher terpenes. Carbon side chains are attached to the B-ring via Michael additions and Reformatzky reactions.Zusammenfassung. Es werden selektive Oxidationsreaktionen am Abietinsäuregerüst beschrieben, die zur Einführung von Sauerstoffunktionen am B-bzw. C-Ring führen. Die Oxidationsprodukte können zur Synthese höherer Terpenderivate verwendet werden. An einzelnen Verbindungen werden Aufbaureaktionen beschrieben (Michael-Addition, Reformatzky-Reaktion), die es gestatten, Kohlenstoffketten an den B-Ring zu knüpfen.

Synthesis of new 4-phenylpyrimidine-2(1H)-thiones and their potency to inhibit COX-1 and COX-2

Several new 4-phenylpyrimidine-2(1H)-thiones have been prepared and investigated for their potencies to inhibit COX-1 and COX-2 enzymes, and COX-2 expression in THP-1 cells. Structure-activity-relationships and physicochemical parameters are discussed. Pharmacophore screening and docking studies were carried out for the most active compound.

Sesquiterpenes and Phenolic Compounds from Achillea clypeolata Sesquiterpenes and Phenolic Compounds from Achillea clypeolata

The investigation of a dichloromethane extract of flower heads of Achillea clypeolata collected in Bulgaria led to the isolation of one guaiane (4,10,11-trihydroxy-guaiane, 1), four eudesmanes (4(15)-eudesmene-1β ,11-diol, 2, clypeotriol, 3, 3-epi-clypeotriol, 4, cryptomeridiol, 5), one diterpene (sugeroside, 6) and two phenolic compounds (centaureidin, 7 and scopoletin, 8). Their structures were elucidated by UV/vis, EI- and CI-MS as well as by one- and two-dimensional NMR experiments. 4,10,11-Trihydroxy-guaiane (1) and 3-epi-clypeotriol (4) are reported here for the first time.