Vlatka Vajs

Oxidation products of hyperforin from Hypericum perforatum

The isolation of two oxidation products of hyperforin from the aerial parts of Hypericum perforatum and their structure determination by means of 2D NMR methods is reported. The products had the same 1-(2-methyl-1-oxopropyl)-2,12-dioxo-3,10 beta-bis(3-methyl-2-butenyl)-11 beta-methyl-11 alpha-(4-methyl-3-pentenyl)-5-oxatricyclo[6.3.1.0(4,8)]-3-dodec ene skeleton. In addition, one of them, with the same number of carbons as hyperforin (C35H52O5), contained a 1-methyl-l-hydroxyethyl group in the 6 beta-position, whereas the other compound (a hemiacetal, C32H46O5), presumably a degradation product of hyperforin, exhibited a 6-hydroxy function. The latter was an inseparable mixture of 6 alpha- and 6 beta-hydroxy epimers undergoing (according to phase sensitive NOESY) mutual interconversion.

Guaianolides from Centaurea nicolai: antifungal activity

A new guaianolide, 3-deacetyl-9-O-acetylsalograviolide A, along with four known closely related lactones, salograviolide A, 9-O-acetylsalograviolide A, kandavanolide and salograviolide B were detected in the aerial parts of the flowering plant Centaurea nicolai. Antifungal tests performed on salograviolide A and its 9-O-acetyl and 3-O-deacetyl-9-O-acetyl derivatives revealed inhibitory activity against Aspergillus niger, A. ochraceus, Penicillium ochrochloron, Cladosporium cladosporoides, Fusarium tricinctum and Phomopsis helianthi. Neither of them was active against Trichoderma viride.

Xanthones from Swertia punctata

Isolation of 1-O-primeverosyl-3,8-dihydroxy-5-methoxyxanthone and 1-O-gentiobiosyl-3,7-dimethoxy-8-hydroxyxanthone, along with five known xanthones, isobellidifolin, methylbellidifolin, isoswertianin, methylswertianin and norswertianin-1-O-beta-D-glucoside, from the roots of Swertia punctata is reported. In the aerial parts four xanthones, bellidifolin, methylbellidifolin, swertianolin and mangiferin, and flavone-C-glucoside, isoorientin were identified. The chemotaxonomic and pharmacological significance of these results is discussed.

Isolation and Biological Evaluation of Jatrophane Diterpenoids from Euphorbia dendroides

From the Montenegrin spurge Euphorbia dendroides, seven new diterpenoids [jatrophanes (1-6) and a tigliane (7)] were isolated and their structures elucidated by spectroscopic techniques. The biological activity of the new compounds was studied against four human cancer cell lines. The most effective jatrophane-type compound (2) and its structurally closely related derivative (1) were evaluated for their interactions with paclitaxel and doxorubicin using a multi-drug-resistant cancer cell line. Both compounds exerted a strong reversal potential resulting from inhibition of P-glycoprotein transport.

Essential Oil of Anthemis montana

Abstract The essential oil of Anthemis montana L. (Asteraceae) has been analyzed using GC and GC/MS. Forty-two components were identified. The major fractions belonged to α-thujone (46.9%), β-thujone (16.0%), and trans-chrysanthemyl acetate (11.3%) amounting up to 74.2% of the total oil content.

Composition and Antibacterial Activity of Achillea asplenifolia Essential Oil

Abstract The oil of a wild growing population of Achillea asplenifolia Vent, was studied for yield, composition and antibacterial activity. The major components in the oil were β-caryophyllene (17.6%), germacrene D (15.6%) and chamazulene (13.3%). In an antibacterial diffusion assay, the oil showed activity against all tested Gram-negative bacteria (Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa) and Gram-positive Staphylococcus aureus.

Composition and Antibacterial Activity of Achillea chrysocoma Essential Oil

Abstract Essential oil of Achillea chrysocoma Friv. was investigated for composition and antibacterial activity. Twenty-eight identified compounds constituted 91.5% of the oil. The main compounds of the oil were borneol (10.1%), terpinen-4-ol (9.2%), cis-p-menth-2-en-1-ol (8.2%) and trans-p-menth-2-en-1-ol (7.9%). Antibacterial tests showed pronounced activity of the oil against Gram-negative bacteria Klebsiella pneumoniae and Pseudomonas aeruginosa.

Antioxidant properties of raspberry seed extracts on micronucleus distribution in peripheral blood lymphocytes

This study addresses in vitro effects of raspberry (Rubus idaeus) seed extracts (RSE) on the frequency of micronuclei. We evaluated the effects of three different extracts (50%, 80%, and 100% methanol) in doses of 1.4, 4.2, and 8.4 microg/mL, per 5 mL culture using cytochalasin-B micronucleus (CBMN) assay in peripheral human lymphocytes. The frequency of MN was scored in binucleated (BN) cells. The nuclear proliferation index was also calculated. The distribution of polyphenolic compounds in RSEs was determined using LC/UV/ESI-TOF MS. The identified 37 compounds comprised flavanol monomers and oligomers, as well as varieties of ellagitannin components. Treatment of lymphocytes with RSEs induced a significant decrease in the frequency of micronuclei by 80%. These results demonstrate that the constituents of RSEs may be important in the prevention of oxidative lymphocyte damage by reactive oxygen species and may also reduce the level of DNA damage. These findings support the potential benefits of polyphenolic compounds from raspberry seeds as efficient antioxidants.

Highly oxygenated guaianolides from Anthemis cretica subsp. cretica

Two new guaianolides, i.e. anthemolide B and 8-O-angeloyl-9-O-acetylanthemolide B, in addition to 12 known closely related guaianolides were identified in the aerial parts of the flowering plant Anthemis cretica subsp. cretica.

Study of forced degradation behavior of Eletriptan hydrobromide by LC and LC–MS and development of stability-indicating method

The objective of the present study was to report the stability profile of novel antimigrain drug Eletriptan hydrobromide based on the information obtained from forced degradation studies. The drug was subjected to acid (0.1-1 mol L(-1) HCl), neutral and base (0.1-1 mol L(-1) NaOH) hydrolysis and to oxidative decomposition (3-15% (v/v) H(2)O(2)). Photolysis and thermo degradation at 75 degrees C were carried out in methanol solution and in solid state with both Eletriptan hydrobromide bulk drug and the tablet formulation. The products formed under different stress conditions were investigated by LC and LC-MS. The experimental conditions for LC were chosen by employing experimental design and multicriteria decision making methodology. These powerful tools enabled the accomplishment of satisfactory resolution with the shortest possible analysis time. Analytes were separated on a C(18) column (XTerra, 150 mm x 3.9 mm, 5 microm) with the mobile phase composed of methanol-water solution of TEA (pH 6.52, 1%, v/v) (30:70, v/v) pumped at 1 mL min(-1) flow rate. The column temperature was set at 50 degrees C and the detection at 225 nm using DAD detector. The LC method was suitably modified for LC-MS analysis which was further used to characterize the arisen degradation products. The possible degradation pathway was outlined based on the results. The drug appeared to be instable towards every stress condition but oxidation. The stability was not jeopardized even under more exaggerated conditions such as increased temperature of the solutions to 75 degrees C, increased strength of acid/alkali solutions and prolonged testing period. Validation of the LC-DAD method was carried out in accordance with ICH guideline. The method met all required criteria and was applied when testing the commercially available tablets.