Probing the existence of chemotypes of Helleborus odorus Waldst. & Kit. ex Willd. by essential oil analysis: a multivariate approach

Helleborus species (family Ranunculaceae) are evergreen, rhizomatous plants with scientifically demonstrated biological/pharmacological activities [1]. Nonetheless, the essential oils of the genus are general poorly phytochemically and pharmacologically investigated. Helleborus odorus Waldst. & Kit. ex Willd. (‘fragrant hellebore’ or ‘kukurek’ in Serbian) is a highly toxic plant species growing on hillsides and in forests of the submediterranean region. Up to now, steroid-related compounds (saponins, ecdysteroids, bufadienolides), fatty acids and other lipids, and sugars of H. odorus were investigated. However, to the best of our knowledge, there are no previous studies of the essential oil of this species.                Analyses by GC and GC/MS of four essential-oil samples obtained from dry aerial parts and roots of H. odorus allowed the identification of 229 components, comprising 88.8-92.2% of the total oil composition. The major identified volatile compounds were 1-pentacosene (0.0-52.8%), tricosane (0.0-15.1%), linoleic acid (0.0-11.8%), trans-phytol (0.0-12.4%), hexadecanoic acid (3.7-16.8%), (2E,4E)-decadienal (tr-13.8%), linalool (0.5-6.0%) and hexanal (0.0-7.4%). In general, there were qualitative and quantitative variations noted in the compositions between the H. odorus essential-oil samples from different locations. The most discernable differences included a change in the content of the major constituent (1-pentacosene). These differences motivated us to explore (by multivariate statistical analysis (MVA)) the possible existence of several chemotypes of this species using essential-oil compositional data. Agglomerative hierarchical clustering and principal component analysis of the chemical data on the volatiles of the herein studied and additional 37 oil samples of Ranunculaceae showed a close relationship of Helleborus with other Ranunculaceae genera and the existence of only one chemotype of this species in the Serbian flora

Phytomedical investigation of Najas minor All. in the view of the chemical constituents

Plants are an abundant natural source of effective antibiotic compounds. Phytomedical investigations of certain plants haven’t still been conducted. One of them is Najas minor (N. minor), an aquatic plant with confirmed allelopathy. Research conducted in this study showed the influence of water and ethyl acetate extracts of N. minor on microorganisms, in the view of chemical profiling of volatile constituents and the concentrations of total phenols, flavonoids and tannins. Antimicrobial activity was defined by determining minimum inhibitory and minimum microbicidal concentrations using microdilution method. Influence on bacterial biofilm formation was performed by tissue culture plate method. The total phenolics, flavonoids and condensed tannins were determined by Folin-Ciocalteu, aluminum chloride and butanol-HCl colorimetric methods. Chemical profiling of volatile constituents was investigated by GC and GC-MS. Water extract didn't have antimicrobial activity below 5000 µg/mL. Ethyl acetate extract has shown strong antimicrobial activity on G+ bacteria - Staphylococcus aureus PMFKGB12 and Bacillus subtilis (MIC < 78.13 µg/mL). The best antibiofilm activity was obtained on Escherichia coli ATCC25922 (BIC50 at 719 µg/mL). Water extract had higher yield. Ethyl acetate extract had a significantly greater amount of total phenolics, flavonoids and tannins. As major constituent hexahydrofarnesyl acetone was identified. The ethyl acetate extract effected only G+ bacteria, but the biofilm formation of G-bacteria was suppressed. There was a connection between those in vivo and in vitro effects against pathogenic bacterial biofilm formation. All of this points to a so far unexplored potential of N. minor

SYNTHESIS OF NEW CONDENSED COUMARIN DERIVATIVES UDC 537.569/.534.8

Abstract. Reactions of 4-chloro-2-oxo-2H-chromene-3-carbonitrile (1) with 4-methylpyridin-2-ylamine (2) and 6-methoxy-benzothiazol-2-ylamine (3) in acetonitrile containing a catalytic amount of triethylamine gave the new coumarin derivatives 7-imino-10-methyl-7H-5-oxa-7a,12-diaza-benzo[a]anthracen-6-one (4) and 7-imino-10-methoxy-7H-5-oxa-12thia-7a,13-diaza-indeno[1,2-b]phenanthren-6-one (5) in 52 and 39 % yields, respectively. The novel compounds were subjected to acid hydrolysis giving the corresponding oxoderivatives 10-methyl-5-oxa-7a,12-diaza-benzo[a]anthracene-6,7-dione (6) and 10methoxy-5-oxa-12-thia-7a,13-diaza-indeno[1,2-b]phenanthrene-6,7-dione (7) in 64 and 58 % yields, respectively. The structural assignments of the synthesized compounds were based on elemental analyses, IR and proton NMR spectra. Key words: synthesis, hydrolysis, structural determinatio

Synthesis of Small Libraries of Natural Products: Part II: Identification of a New Natural Product from the Essential Oil of <i>Pleurospermum austriacum</i> (L.) Hoffm. (Apiaceae)

Herein, comprehensive data of NMR, MS, IR, and gas chromatography (RI) obtained by GC-MS on commonly used capillary columns of different polarity (non-polar DB-5MS and polar HP-Innowax) of a series of esters of all constitutional isomers of hexanoic acid with a homologous series of ω-phenylalkan-1-ols (phenylmethanol, 2-phenylethanol, 3-phenylpropan-1-ol, 4-phenylbutan-1-ol, and 5-phenylpentan-1-ol) and phenol, in total 48 chemical entities, were collected. The created synthetic library allowed the identification of a new constituent of the P. austriacum essential oil (3-phenylpropyl 2-methylpentanoate). The accumulated spectral and chromatographical data, as well as the established correlation between RI values and structures of regioisomeric hexanoates, provide (phyto)chemists with a tool that will make future identification of related natural compounds a straightforward task

isparljivi PROIZVODI razlaganja glukozinolata i ETARSKO ULJE VRSTE dESCURAINIA SOPHIA WEB EX PRANTL (BRASSICACEAE)

Volatile constituents obtained by autolysis of aerial and underground parts of D. sophia and the essential oil obtained by hydrodistillation of whole plant samples were analyzed in detail by GC and GC-MS. In total, 71 constituents were identified, accounting for more than 90% of the total peak areas in the chromatograms. Both aerial and underground autolysates contained considerable amounts of lignan arctigenin and cuticular wax compounds. The essential oil was dominated by glucosinolate breakdown product 4-pentenenitrile. Glucosinolate degradation products identified in the essential oil and autolysates, 3-butenyl isothiocyanate, 4-pentenenitrile and allyl isothiocyanate, suggested the presence of gluconapin and sinigrin in this species as the most likely “mustard oil” precursors.HIGHLIGHTSVolatile constituents of Descurainia sophia essential oil and autolysates were analyzed in detail by GC and GC-MS.The analyses allowed the identification of 71 compounds in total.Descurainia sophia contains glucosinolates gluconapin and sinigrin and lignan arctigenin. Detaljnim GC i GC-MS analizama etarskog ulja i isparljivih sastojaka dobijenih autolizom nadzemnog dela i korena vrste Descurainia sophia identifikovano je ukupno 71 jedinjenje, odnosno više od 90% ukupno detektovanih pikova hromatograma. Oba autolizata su sadržala znatne količine sastojaka kutikularnog voska i lignana arktigenina. Najzastupljeniji sastojak etarskog ulja je bio proizvod razlaganja glukozinolata 4-pentenonitril. Degradacioni proizvodi glukozinolata identifikovani u autolizatima i etarskom ulju, 3-butenil-izotiocijanat, 4-pentenonitril i alil-izotiocijanat, ukazuju na prisustvo glukonapina i sinigrina u tkivima ove biljne vrste