Three further dolabellane diterpenoids from Dictyota sp.

A brown alga of the genus Dictyota has yielded three new dolabellane diterpenoids the structures of which were elucidated mainly by spectroscopic methods.     

Seven sesquiterpene lactones from Ferreyanthus species

The investigation of two Ferreyanthus species afforded seven germacranolides which have not been isolated previously. Two derivatives of linalol were also present. The structures were elucidated by spectroscopic methods. Chemotaxonomic relationships are briefly discussed.     

Sesquiterpene lactones from the fruits of smyrnium rotundifolium

In addition to known compounds an investigation of the fruits of Smyrnium rotundifolium afforded four new germacrane derivatives, all closely related to glechomanolide, one being a secogermacrane anhydride. The new compounds were 8,9-epoxy-8,9-secoglechomanolide, 1β,10α-epoxy-4-methoxy-8-hydroxyglechomanolide and 8-oxo-8,9-secoglechomanolide. The structures were assigned by spectral methods as well as by some chemical reactions.     

Thymol derivatives from Eupatorium glechonophyllum

The known 10-acetoxy-8,9-epoxythymolisobutyrate and the new 8,9-dihydroxy-10-acetoxythymolisobutyrate and 8,9,10-trihydroxythymol have been isolated from the thallus of Eupatorium glechonophyllum. The acetonide of the last compound was also obtained. The possibility that the new compounds are artefacts is discussed.     

Eudesmanolides from Pluchea dioscoridis

Reinvestigation of the aerial parts of Pluchea dioscoridis afforded, in addition to known compounds, five new eudesmanolides and a new thiophene derivative. The stereochemistry of one of the eudesmanolides isolated previously has been corrected. The structures were elucidated by spectroscopic methods.     

cDNA macroarray analysis of gene expression changes in rat brain after a single administration of a 2-aminoadamantane derivative

The Atlas Rat cDNA Expression Array (BD Biosciences, United States) has been used to analyze changes in the expression of 588 genes in rat brain cells in response to a single administration of Ladasten, a 2-aminoadamantane derivative that has psychostimulating and anxiolytic effects. The analysis of hybridization on macroarrays, confirmed by the results of real-time quantitative RT-PCR, has demonstrated that Ladasten alters the expression of 12 genes in the rat brain. The GAT3 and CARBH genes are presumed to be pharmacologically important targets of Ladasten. The changes in their activity explain the mechanisms of the anxiolytic and mood-stabilizing effects of the drug. Ladasten has been shown to induce the genes whose products are involved in various signal pathways (APC, Rb, PKCIP, and PMCA), as well as the genes of cytoskeletal proteins (Tub1 and actin), synaptic proteins (SynIA&IB and PLP), and enzymes (Gapdh and NSE). The proteins encoded by these genes are presumably involved in compensatory and/or neuroplastic adaptation to the effects of Ladasten.__________Translated from Molekulyarnaya Biologiya, Vol. 39, No. 2, 2005, pp. 276–285.Original Russian Text Copyright © 2005 by Vakhitova, Yamidanov, Vakhitov, Seredenin.     

Polar acyclic diterpenoids from Bifurcaria bifurcata (Fucales, Phaeophyta)

From the lipophilic extract of the brown alga Bifurcaria bifurcata collected off the Atlantic coast of Southern Brittany (Quiberon, France), five polar linear diterpenoids have been isolated. These metabolites have been identified as hydroxylated derivatives of 13-oxo- and 13-hydroxygeranylgeraniol. Their structures were characterized on the basis of chemical and spectral evidence including two-dimensional NMR experiments and mass spectrometric techniques. The absolute configuration of the 13-position has been determined, for the 13-hydroxygeranylgeraniol derivatives, to be R by means of a modified Mosher's method and therefore that of 13-hydroxygeranylgeraniol (eleganediol) has been revised. Along with these compounds, three related known geranylgeraniol derivatives were also identified, and these data were used for chemotaxonomical purposes.     

Characterisation of polyphenols by HPLC-PAD-ESI/MS and antioxidant activity in Equisetum telmateia

The antioxidant activity of an aqueous extract (infusion) and respective ethyl acetate fraction of Equisetum telmateia Ehrh. (Equisetaceae), a plant used in traditional medicine for its anti-inflammatory and diuretic properties, has been evaluated by DPPH, TEAC and TBARS assays. A high and significant antioxidant activity was detected in the ethyl acetate fraction. Analysis of the aqueous extract and the ethyl acetate fraction by HPLC-PAD-ESI/MS allowed the identification of the major phenolic compounds as flavan-3-ol, kaempferol and phenolic acid derivatives. Among the flavan-3-ols, A-type proanthocyanidins and afzelechin derivatives were detected as well as the more common B-type procyanidins, B2 and C1, whose identification was further confirmed by HPLC using detection involving chemical reaction with p-dimethylamino-cinnamaldehyde. The results suggest that the anti-inflammatory activity of E. telmateia could be due, at least in part, to the presence of compounds with antioxidant activity.     

Recent advances in asymmetric synthesis of pipecolic acid and derivatives

Summary. This review covers the literature relating to asymmetric syntheses of pipecolic acid derivatives from 1997 to present. This review is organized according to the position and the degree of substitution of the piperidinic cycle. In a first section, syntheses of pipecolic acid itself are described. Then, successively, syntheses of C-3, C-4, C-5, C-6 substituted pipecolic acid derivatives are reported. Finally, syntheses of unsaturated pipecolic acid derivatives are presented before the last part devoted to the polysubstituted pipecolic acid derivatives.