A NOTE ON THE BIOSYNTHESIS OF LONG-CHAIN 3-METHYL-2-ALKANONES FROM THE ROOT ESSENTIAL OIL OF INULA HELENIUM L. (ASTERACEAE)

A predominantly odd-numbered, Gaussian-like distribution of the relative amounts of 3-methyl-2-alkanones, from I. helenium root essential oil, was observed. This distribution pattern indicates that their biosynthesis is related to that of fatty acids and related compounds. Simple (non-branched) 2-alkanones also show an odd carbon number prevalence in plants and other organisms, and it was shown that their biosynthesis indeed proceeds via the acetate pathway. In this paper, we propose three possible biosynthetic pathways by which 3-methyl-2-alkanones could be formed in the plant tissues. The essential distinction between them lies in the way the branching methyl group is introduced. The Gaussian parameter σ for the observed distribution of these ketones could be interpreted as the error introduced by the first elongase enzyme system involved in the biosynthesis of fatty acid-derived compounds. BIOSINTEZA 3-METIL-2-ALKANONA DUGOG UGLJOVODONIČNOG LANCA IZ ETARSKOG ULJA KORENA BILJNE VRSTE INULA HELENIUM L. (ASTERACEAE)3-Metil-2-alkanoni dugog ugljovodoničnog lanca su nađeni u etarskom ulju korena biljne vrste I. helenium L. Uočena je Gausova raspodela njihovih relativnih količina, pri čemu su homolozi sa neparnim brojem C-atoma bili zastupljeniji. Ovakva raspodela ukazuje na to da njihova biosinteza protiče veoma slično kao i biosinteza masnih kiselina i srodnih jedinjenja. 2-Alkanoni sa neparnim brojem C-atoma su, takođe, zastupljeniji kod biljaka i ostalih organizama, a za njih je dokazano da zaista nastaju po gore pomenutom acetatnom biosintetskom putu. Imajući sve ovo u vidu, predložili smo tri moguća biosintetska puta kojim bi 3-metil-2-alkanoni mogli nastati u biljnim tkivima. Osnovna razlika između predloženih puteva je u načinu na koji se uvodi metil račva. Gausov parametar σ uočenih raspodela količina alkana bi se mogao posmatrati kao greška prvog enzimskog sistema elongaze koji učestvuje u biosintezi masnih kiselina i jedinjenja koja se iz njih izvode. HIGHLIGHTSHomologous 3-methyl-2-alkanones (C11–C19) detected in Inula helenium root essential oil had a predominantly odd-numbered Gaussian-like distribution.This specific distribution pattern indicates that their biosynthesis most likely proceeds via the acetate pathway.There are three possible biosynthetic pathways, with a different mode of introducing the methyl branch, by which 3-methyl-2-alkanones could be produced.The observed Gaussian parameter σ could be interpreted as the error of the first elongase enzyme system involved in the biosynthesis of fatty acid-derived compounds

PREFACE TO THE SPECIAL ISSUE OF FU PHYS CHEM TECH, DEDICADED TO PROFESSOR RADOSAV M. PALIĆ ON THE OCCASION OF HIS 70TH BIRTHDAY

 This special issue of FU Phys Chem Tech is dedicated to Professor Radosav M. Palić on the occasion of his 70th birthday. Dr. Palić has made important contributions in many areas of chemistry, his main interest being the chemistry of volatile plant metabolites and their antimicrobial activity. He was the pioneer of the phytochemical research at the University of Niš. The authors of the papers published in this issue (all manuscripts underwent a rigorous peer-review process) are his former students and/or his scientific collaborators, who are grateful to him for his contribution to the development of chemistry not only at the University of Niš but also in Serbia. PREDGOVOR SPECIJALNOM BROJU ČASOPISA FU Phys Chem Tech, POSVEĆENOM PROFESORU RADOSAVU M. PALIĆU, U ČAST NJEGOVOG 70. ROĐENDANAOvaj specijalni broj časopisa FU Phys Chem Tech je posvećen profesoru Radosavu M. Paliću, u čast njegovog 70. rođendana. Dr Palić je dao značajan doprinos različitim oblastima hemije, a najviše se bavio proučavanjem hemije isparljivih biljnih metabolita i njihovom antimikrobnom aktivnošću. Profesor Palić je bio pionir fitohemijskih istraživanja na Univerzitetu u Nišu. Autori radova objavljenih u ovom broju (svi rukopisi su podvrgnuti naučnoj recenziji) su njegovi bivši studenti i/ili saradnici, koji su mu zahvalni na svemu što je on učinio za razvoj hemije ne samo na Univerzitetu u Nišu, već i u Srbiji uopšte

COMPLETE ASSIGNMENT OF 1H- AND 13C-NMR SPECTRA OF ANTHRANILIC ACID AND ITS HYDROXY DERIVATIVES AND SALICYLIC ACID AND ITS AMINO DERIVATIVES

We report on the detailed NMR spectral analyses of amino- or/and hydroxy-substituted benzoic acids: anthranilic (AA), 3-hydroxyanthranilic (3-HAA), 5-hydroxyanthranilic (5-HAA), salicylic (SA), 4-aminosalicylic (4-ASA) and 5-aminosalicylic (5-ASA) acids. According to a literature survey, there are limited, unassigned or even incorrectly assigned spectral data to these benzoic acid derivatives. In order to amend the situation, a complete assignment of 1H- and 13C-NMR spectra of these compounds, recorded in perdeuteriodimethyl sulfoxide (DMSO-d6), based on a combination of 1D- and 2D-NMR experiments, including 1H-1H COSY, NOESY, HSQC and HMBC, was performed. POTPUNA ASIGNACIJA 1H- I 13C-NMR SPEKTARA ANTRANILNE KISELINE I NJENIH HIDROKSI-DERIVATA I SALICILNE KISELINE I NJENIH AMINO-DERIVATAU ovom radu dati su NMR podaci za antranilnu (AA), salicilnu (SA) i regioizomerne (amino)hidroksibenzoeve kiseline, 3-hidroksiantranilnu (3-HAA), 5-hidroksiantranilnu (5-HAA), 4-aminosalicilnu (4-ASA) i 5-aminosalicilnu (5-ASA) kiselinu. Kako je pretragom literature utvrđeno da su do sada objavljeni NMR podaci za pomenute derivate benzoeve kiseline nepotpuni, neasignirani ili čak i pogrešno asignirani, izvršena je kompletna asignacija signala u 1H- i 13C- NMR spektrima snimljenim u deuterisanom dimetil-sulfoksidu (DMSO-d6) kombinovanjem 1H- i 13C-NMR sa 1H-1H COSY, NOESY, HSQC i HMBC eksperimentima. HIGHLIGHTSThe NMR spectra of anthranilic, 3- and 5-hydroxyanthranilic, salicylic, 4- and 5-aminosalicylic acids were recorded in DMSO-d6.A literature survey revealed limited, unassigned or even incorrectly assigned spectral data for these amino- or/and hydroxy-substituted benzoic acids.Complete assignment of NMR spectral data was based on a combination of 1H-and 13C-NMR 1D- and 2D-experiments (1H–1H COSY, NOESY, HSQC, HMBC).The 13C-1H coupling constants, previously unavailable in the literature, were derived from the proton-coupled 13C NMR spectra.In the 1H-coupled 13C NMR spectrum of 5-aminosalicylic acid two signals appeared as second-order multiplets, although first-order ones were expected

Chemical composition and screening of the antimicrobial and antioxidative activity of extracts of Stachys species

GC and GC/MS analyses of the diethyl ether and ethyl acetate extracts obtained from the aerial parts of Stachys germanica subsp. heldreichii (Boiss) Hayek, Stachys iva Griseb., Stachys plumosa Griseb. and Stachys scardica Griseb., Balkan peninsula endemics, were performed. One hundred and seventy-nine constituents, accounting for 88.8–98.1% of the total composition of the extracts, were identified. The common feature of the diethyl ether extracts was the high content of terpenoids and fatty acid-derived compounds, while the common feature of the ethyl acetate extracts was the prevalence of fatty acid-derived compounds. A disk diffusion method was used for the evaluation of the antimicrobial activities of the extracts against a panel of microorganisms (bacteria: Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Salmonella enteritidis; fungi: Aspergillus niger and Candida albicans). The total antioxidant capacity of the extracts was evaluated by the phosphomolybdenum method. The preliminary bioassay results indicated that the diethyl ether extract of S. plumosa could be a possible source of antioxidant and antimicrobial compounds

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

The isovalerate and 2-methylbutanoate of artemisia alcohol–new compounds from Artemisia annua L. essential oil

Artemisia annua L. (sweet wormwood) is an essential oil (EO)-rich, medicinally valuable plant species from the Asteraceae family [1]. During the analysis of the biologically active A. annua EO sample (hydrodistilled from the dry aboveground parts of the plants; oil yield 0.2%, w/w; the main components (relative abundance): artemisia ketone (35.7%), a-pinene (16.7%), 1,8-cineole (5.5%), artemisyl alcohol (4.8%), and trans-pinocarveol (4.8%) [1]), we have detected two minor compounds, AA1 and AA2 (0.06% and less than 0.05% of the total oil, with RI (DB5-MS) values of 1367 and 1373, respectively) with practically identical mass spectral (MS) fragmentation patterns (EI, 70 eV; m/z (rel. int.)): 169(15), 85(100), 57(38), 41(17). The comparison of GC (≈300 unit higher RI values) and MS data of AA1 and AA2 with those of artemisyl acetate (often present in EOs containing artemisia ketone and artemisia alcohol) suggested these might be esters of artemisia alcohol and (isomers of) pentanoic acids. To confirm this tentative identification, and possibly detect some additional AA1 and AA2 homologs, we prepared esters of artemisia alcohol and valeric, isovaleric, 2-methylbutanoic, butanoic, isobutanoic and propanoic acids (Steglich esterification; the starting alcohol was obtained by LiAlH4 reduction of artemisia ketone isolated from the EO). Co-injection of the EO sample with synthetic standards confirmed AA1 and AA2 were artemisyl isovalerate and artemisyl 2-methylbutanoate (diastereomer not determined), respectively (Fig. 1). Detailed re-analysis of the EO revealed the presence of initially undetected trace amounts of artemisyl acetate. The results of this work once again confirm the importance of natural product-inspired libraries of synthetic compounds in the analysis of EOs, especially when it comes to the detection and identification of trace constituents

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

FOUR CASES OF APPENDICEAL NEUROMA MIMICKING ACUTE APPENDICITIS

Herein we report four cases of appendiceal neuroma found during a short (one month) monitoring period in patients with severe pain in the lower right abdominal quadrant that underwent appendectomies. Tissue samples were routinely processed to obtain histological sections that were stained with hematoxylin and eosin (H&E) and further with anti-S100 protein antibody. Characteristics of appendiceal neuroma were noted in these cases and they included the absence of mucosal and lymphoid tissue of the appendices, stroma with spindle-shaped cells that were positively stained with anti-S100 protein antibody. This clinical entity is important due to a possible misdiagnosis with acute appendicitis or exacerbation of inflammatory bowel disease and great attention should be paid during the clinical evaluation of similar symptoms.Key words: appendiceal neuroma, misdiagnosis, lumen obliteration, immunohistochemistry, S100 protei

Volatiles of Pulicaria vulgaris Gaertn. (Asteraceae)

The genus Pulicaria (tribe Inuleae of the Compositae family) consists of ca. 100 species with a distribution from Europe to North Africa and Asia, particularly around the Mediterranean [1]. A number of compounds from Pulicaria species (flavonoids, sesquiterpenoids, and diterpenoids) possess significant bioactivities, and they could be promising candidates for the development of potential drugs [1]. In the continuation of our investigations of the secondary metabolites of plant taxa from the Serbian flora, we have studied the chemical composition of Pulicaria vulgaris Gaertn. essential oil. Pulicaria vulgaris is a rare plant species, with golden-yellow flowers, growing on sandy, stony places. To the best of our knowledge, there are no previous studies on either the volatile or nonvolatile secondary metabolites of this species. Analyses by GC and GC/MS of an essential-oil sample obtained from air-dried aerial parts allowed the identification of 106 components (most of which were identified by at least two independent means (mass spectrum and retention index matching)). Sesquiterpenes constituted the most abundant compound class, representing 86.4% of the total essential oil. The remaining part of the essential-oil sample was comprised of monoterpenes and fatty acid-related compounds, 5.5 and 2.5%, respectively. The bulk of the oil was comprised of two oxygenated sesquiterpenoids–epi-α-cadinol (23.3%) and presilphiperfolane-7,8-diol (46.4%). No plant species other than P. vulgaris are characterized by the presence of presilphiperfolane-7,8-diol. This fact may be of chemotaxonomic/biosynthetic significance since presilphiperfolanes belong to rare triquinane-type sesquiterpenes that represent precursors of angular and propellane triquinane sesquiterpenes

The floral scent of Dianthus cruentus Griseb. (Caryophyllaceae)

The genus Dianthus L. (Caryophyllaceae) comprises over 300 species of herbaceous plants that are spread over a vast area, especially in the Mediterranean region. Species of this genus, represented with 38 taxa in the Serbian flora, have attracted attention due to the very beautiful flower color combinations ranging from white to deep purple [1]. This characteristic pigmentation, among several other morphological traits, distinguishes Dianthus from other genera within the family Caryophyllaceae, although the evolutionary progress, diversification and the subdivision of the genus still remain controversial [1].                Although Dianthus species, especially the flowers, are utilized ethnopharmacologically, only few secondary metabolites, besides pigments, have been studied in detail [1]. A SciFinder search gives back around 4,000 reports dealing with Dianthus species, however, less than forty dealt with the analysis of secondary metabolites of the taxa from this genus. Some of the identified constituents displayed a great biological/pharmacological potential, as well as a huge significance for the pollination biology and taxonomy.                Dianthus cruentus Griseb. is a highly valued plant species due to the fragrance and blood-red color of its flowers. Strangely, there are no previous reports on its chemical composition in the literature. In this study, we performed the first GC-MS analysis of the volatile constituents of D. cruentus flowers in order to possibly detect and identify its odoriferous components.                Only 24 constituents were identified, many of which were easily recognized as having odorous properties. The floral volatiles were made up mainly of fatty acid-derived compounds and shikimate metabolites. The major identified volatile compounds were heptanal, benzyl alcohol, heptanoic acid, maltol, and phenethyl alcohol. All major constituents are well known for its characteristic scent e.g. maltol (odor of cotton candy and caramel), phenethyl alcohol (pleasant floral odor), heptanal (strong fruity odor) etc. Although, maltol might also be an artifact of the analytical procedure and not a true constituent of D. cruentus flowers