Further sesquiterpene lactones from Viguiera robusta and the potential anti-inflammatory activity of a heliangolide: inhibition of human neutrophil elastase release.

In addition to known heliangolides, a new eudesmanolide was isolated from the leaf rinse extract of Viguiera robusta (Asteraceae). Structural elucidation was based on spectral analysis. It is the first report on eudesmanolides in members of the subgenus Calanticaria of Viguiera. In this work, the main isolated compound, the furanoheliangolide budlein A, besides its previously reported in vitro and in vivo anti-inflammatory activities, inhibited human neutrophil elastase release. The inhibition was at the concentration of (16.83 +/- 1.96) microM for formylated bacterial tripeptide (fMLP) stimulation and (11.84 +/- 1.62) microM for platelet aggregation factor (PAF) stimulation, being slightly less active than the reference drug parthenolide. The results are important to demonstrate the potential anti-inflammatory activities of sesquiterpene lactones and corroborate the previous studies using other targets.

Detection of flavonoids in glandular trichomes of Chromolaena species (Eupatorieae, Asteraceae) by reversed-phase high-performance liquid chromatography

In this work, twelve flavonoids were detected in glandular trichomes of two species of Chromolaena through the glandular microsampling technique and HPLC-UV-DAD analysis. This is the first time that the accumulation of flavonoids in glandular trichomes of the genus Chromolaena is reported. Based on the results, we suggest that this technique can be an useful tool in the search of new compounds with medicinal properties as well as in chemotaxonomic studies of Eupatorieae.

Neste trabalho 12 flavonóides foram detectados nos tricomas glandulares de duas espécies de Chromolaena através do emprego da técnica de microamostragem de tricomas glandulares, associada à análise por CLAE. Esta é a primeira vez que se relata o acúmulo de flavonóides em tricomas glandulares no gênero. Com base nos resultados obtidos, podemos sugerir que esta técnica pode ser uma ferramenta útil na busca de substâncias com propriedades medicinais e em estudos quimiotaxonômicos de Eupatorieae.

Sesquiterpene lactones from Dimerostemma species (Asteraceae) and in vitro potential anti-inflammatory activities.

Two Brazilian species of Dimerostemma (Asteraceae) were chemically investigated. Two known sesquiterpene lactones (STLs), a germacrolide and an eudesmanolide, were isolated from D. episcopale while D. brasilianum afforded the new germacranolide 1beta,5beta/10alpha-trihy-droxy-8alpha-angeloyloxy-germacra-3,11(13)-dien-6alpha,12-olide in addition to a known one. Structure identification based on NMR and MS analyses. 1beta,10alpha,4alpha,5beta-Diepoxy-8alpha-angeloyloxy-costunolide isolated from D. brasilianum was studied for its anti-inflammatory activity. This STL completely inhibited DNA binding of the transcription factor NF-kappaB at a concentration of 5 microm and 10 microM in Jurkat T and Raw 264.7 cells, respectively. Elastase release from human neutrophils was reduced to 50% at a concentrations of 23 microM after stimulation with PAF and of 27 microM after stimulation with fMLP without showing cytotoxic effects. Additionally, elastase was also directly inhibited.

Optimisation of a human neutrophil elastase assay and investigation of the effect of sesquiterpene lactones.

Neutrophil granulocytes are effector cells in innate and humoral immunity. They are involved in inflammatory processes by releasing pro-inflammatory enzymes, such as the human neutrophil elastase (HNE). We here report an optimisation of an HNE release assay using microplates. Special attention has been directed to overcome the often observed activation of neutrophils during isolation from fresh blood. This so-called basal stimulation can take place without addition of external stimulants and can cause severe problems during the assay. We demonstrated that bovine serum albumin (BSA), lipopolysaccharide (LPS), use of different blood donors, heparin and ethylenediaminetetraacetic acid (EDTA) do not cause basal stimulation, but may be due to mechanical stress and the immune system of the blood donor. Here, the number of eosinophils may play a role in the induction of activation. Basal stimulation was overcome when a hypertonic solution, such as sucrose- with N-(2-hydroxyethyl)-piperazine-N'-2-ethanesulfonic acid (HEPES) buffer, was used during centrifugation and the isolated granulocytes were left in phosphate buffered saline (PBS) for 30 min before stimulation. Sesquiterpene lactones (SLs), known for their anti-inflammatory activity were used for evaluation of the assay and were observed to inhibit HNE release at micromolar concentrations. Whereas N-formyl-methionyl-leucylphenylalanine (fMLP), platelet-activating factor (PAF) and basal stimulation resulted in similar IC50 values, phorbol-12-myristate-13-acetate (PMA) as a stimulant needed higher concentrations of SLs. The molecular inhibitory mechanism of SLs is discussed.

Quantitative determination of enhydrin in leaf rinse extracts and in glandular trichomes of Smallanthus sonchifolius (Asteraceae) by reversed-phase high-performance liquid chromatography.

A simple, reliable and rapid reversed-phase HPLC-PAD procedure for the characterisation and quantitative determination of the anti-diabetic sesquiterpene lactone enhydrin (1) from Smallanthus sonchifolius (yacón) has been evaluated and validated. The approach focused on the analysis of various leaf rinse extracts, as well as the glandular trichomes of intact leaves, in which 1 was the major compound detected. The best sample preparation of a rinse extract yielded 0.67 mg/mL of 1, whilst a rapid rinse of a small piece of one dried leaf gave 0.09 mg/mL of 1; the highest concentration obtained from a glandular extract was 0.07 mg/mL. The dried leaves of S. sonchifolius were found to contain a total of 0.97% of 1.

Guaianolides from Viguiera gardneri inhibit the transcription factor NF-kappaB.

Five guaianolides and a germacrolide were isolated from the leaf rinse extract of Viguiera gardneri (Asteraceae), together with known compounds. All compounds were detected in glandular trichomes collected from the leaves and were analyzed by HPLC. Structure elucidation was based on the analysis of spectroscopic data. Low energy conformations were obtained by quantum mechanical calculations. Three closely related guaianolides which were isolated as the main compounds were studied for their anti-inflammatory activity using the transcription factor NF-kappaB as molecular target. NF-kappaB DNA binding was inhibited at sesquiterpene lactones concentrations of 10 or 50 microM.