A. Karioti

Secondary metabolites from Stachys ionica

Nine flavonoids, two iridoids, and one sesquiterpene were isolated from Stachys ionica. Its chemical profile appears to be completely different from other species of Stachys growing in Greece. This differentiation is correlated to the distribution of S. ionica, confined to the Ionian Islands, and therefore, well-isolated from the rest of the species.

Trypanocidal, leishmanicidal and cytotoxic effects of anthecotulide-type linear sesquiterpene lactones from Anthemis auriculata

Trypanosomiasis and leishmaniasis pose major public health threats for many countries, particularly those in sub-Saharan Africa and South America. In the present study, we evaluated the in vitro antiprotozoal activity of three irregular, linear sesquiterpene lactones recently isolated from Greek Anthemis auriculata, namely anthecotulide (1), 4-hydroxyanthecotulide (2) and 4-acetoxyanthecotulide (3). Trypomastigote forms of Trypanosoma brucei rhodesiense and T. cruzi as well as axenic amastigotes of Leishmania donovani were used for testing. The cytotoxic potential of the compounds was also assessed against mammalian (rat) skeletal myoblasts (L6 cells). All compounds showed potent trypanocidal and leishmanicidal activity. 4-Hydroxyanthecotulide (2) appeared to be the most active compound against all parasites, particularly towards T. b. rhodesiense (IC(50) 0.56 microg/ml), whereas 4-acetoxyanthecotulide (3) was the least active. All three metabolites possessed toxicity on mammalian cells, which might limit their use as antiprotozoal agents.

Chemical and principal-component analyses of the essential oils of Apioideae taxa (Apiaceae) from central Balkan.

The volatile constituents of the essential oils of 23 taxa belonging to the Apioideae subfamily were studied in detail. The investigated taxa were Pimpinella serbica (Vis.) Bentham & Hooker, Libanotis montana Cr., Cnidium silaifolium (Jacq.) Simk. ssp. orientale (Boiss.) Tutin, Bupleurum praealtum L., B. sibthorpianum S.u2005S. var. diversifolium (Roch.) Hay, Aegopodium podagraria L., Torilis anthriscus (L.) Gmel., Orlaya grandiflora (L.) Hoffm., Laserpitium siler L., Laser trilobum (L.) Brokh., Chaerophyllum aureum L., C. hirsutum L., C. temulum L., Pastinaca sativa L., P. hirsuta Pancic., Tordylium maximum L., Physospermum cornubiense (L.) DC., Peucedanum alsaticum L., P. oreoselinum (L.) Moench, P. cervaria (L.) Cuss., P. austriacum (Jacq.) Koch, P. longifolium W. et K., and P. officinale L. All of these species grow wild in the central part of the Balkan Peninsula. The essential oils were found to be complex mixtures of various compounds, more than 100u2005constituents being in each taxon, with contributions of main products never exceeding 25% of the total content. Sesquiterpene hydrocarbons were found to be the main group of constituents of all taxa, except for Peucedanum species, where monoterpene hydrocarbons were identified as the main components. The chemotaxonomic value of the essential‐oil composition is discussed according to results of principal‐component analysis (PCA). The essential‐oil composition mainly reflects current taxonomic relationships between the investigated taxa.

Inhibiting enoyl-ACP reductase (FabI) across pathogenic microorganisms by linear sesquiterpene lactones from Anthemis auriculata

Enoyl-ACP reductase (FabI) is a key enzyme of the type II fatty acid biosynthesis (FAS-II) pathway and a validated antimicrobial target. In the current study, three linear sesquiterpene lactones obtained from Anthemis auriculata, namely anthecotulide (1), 4-hydroxyanthecotulide (2) and 4-acetoxyanthecotulide (3) were evaluated for specific inhibitory effects against the FabI enzyme from three pathogenic microorganisms, Plasmodium falciparum (PfFabI), Mycobacterium tuberculosis (MtFabI) and Escherichia coli (EcFabI). In addition, the compounds were also tested against two elongation enzymes from the plasmodial FAS-II system, beta-ketoacyl-ACP reductase (PfFabG) and beta-hydroxyacyl-ACP deydratase (PfFabZ). The compounds showed clear differentiation in inhibition of FabI enzymes from different microorganisms. Anthecotulide (1) was most active against MtFabI (IC(50) 4.5 microg/ml), whereas the oxygenated derivatives thereof (compounds 2 and 3) specifically inhibited plasmodial FAS-II enzymes, PfFabI and PfFabG (IC(50) values 20-75 microg/ml). All compounds were inactive towards EcFabI. In whole cell assays, all three compounds exhibited antimalarial and antibacterial activities.

Secondary metabolites from Centaurea deusta with antimicrobial activity

The aerial parts of Centaurea deusta Ten. afforded in addition to several known compounds, mainly sesquiterpene lactones, one new eudesmanolide and one new elemane derivative. Structures of the new compounds were elucidated by spectroscopic methods. The in vitro antifungal and antibacterial activities of the isolated compounds was tested, using the microdilution method. All compounds tested showed high antifungal activity.

A novel sesquiterpene lactone from Centaurea pullata: Structure elucidation, antimicrobial activity, and prediction of pharmacokinetic properties

A novel elemanolide with an alpha-methyl-gamma-lactone moiety, 8alpha-O-(4-hydroxy-2-methylenebutanoyloxy)melitensine, in addition to four known sesquiterpene lactones also bearing the same lactone ring, melitensin, 11beta,13 dihydrosalonitenolide, 8alpha-hydroxy-11beta,13-dihydro-4-epi-sonchucarpolide, and 8alpha-hydroxy-11beta,13-dihydro-onopordaldehyde have been isolated from the aerial parts of Centaurea pullata. The in vitro antibacterial and antifungal activities of the isolated sesquiterpene lactones were tested against six bacteria and eight fungal species, using a microdilution method. All compounds tested showed greater antibacterial and antifungal activities than the positive controls used. Moreover, the pharmacokinetic profile of these compounds was investigated using computational methods.

Constituents of the Distilled Essential Oils of Citrus reticulata and C. paradisi from Nigeria

Abstract Hydrodistilled essential oils from the fruit of Citrus paradisi Macfad. (Rutaceae), and fruit peel and leaf of Citrus reticulata L. occurring in Nigeria, were studied by GC and GC/MS on two separate columns. All oils yielded predominantly comparable amounts of monoterpene hydrocarbons (81.0–98.0%). Limonene was the main constituent in mandarin (67.0%) and grapefruit (94.2%) peel oils, while γ-terpinene (53.0%) and linalool (16.1%) were the chief constituents of mandarin leaf oil. Marked differences existed in the composition of the major and minor constituents of tangerine oils. Aliphatic aldehydes and alcohols were also detected in all oils.

Essential oil constituents of Klainedoxa gabonensis Pierre ex Engl (Irvingiaceae), Brachystegia nigerica Hoyle et A. Jones (Caesalpinioideae) and Acalypha segetalis (Muell.) Arg., (Euphorbiaceae)

Abstract The volatile composition of Klainedoxa gabonensis Pierre ex Engl., Brachystegia nigerica Hoyle et A. Jones and Acalypha segetalis Muell Arg., has been studied. The essential oils were obtained by hydrodistillation in a modified Clevenger-type apparatus while the analyses were performed by GC and GC/MS. The main constituents of K. gabonensis oils were geranyl acetone (13.8%), β-bourbonene (11.1%) and (?)-α-ionone (10.5%) from the leaves; linalool (17.4%), 1, 8-cineole (9.9%) and 1-octen-3-ol (8.0%) from the stem bark, with 1, 2, 3-trimethylbenzene (9.8%), 1-ethyl-2-methyl benzene (9.1%), pentyl benzene(9.1%) and methyl salicylate (9.1%) occurring in higher proportions in the root oil. The leaf oil of B. nigerica was dominated by α-pinene (17.7%), β-selinene (12.5%) and α-gurjunene (8.8%). The main compounds identified in the oil of A. segetalis were α-pinene (29.8%), 1, 8-cineole (16.2%), (?)-phytol (11.8%) and δ-3-carene (9.8%). The present investigation may represent the first of its kind on the characterization of the volatile constituents of the studied plant samples

Analysis of the leaf Oil of Syzygium malaccense Merr. et Perry from Nigeria

Abstract The hydrodistilled essential oil from fresh leaves of Syzygium malaccense Merr. et Perry. grown in Nigeria has been studied by GC and GC/MS for the first time. Identification of the substances was made by comparison of mass spectra and retention indices with literature records. The oil was largely composed of monoterpenes (61.1%) characterized mainly by (+)-α-pinene (7.3%), (−)-β-pinene (8.0%), p-cymene (13.5%), and α-terpineol (7.5%). The sesquiterpenes constituted 30.8% of the oil with (−)-β-caryophyllene (9.0%) as the major component.

Essential Oils of Nigeria II: Analysis of the leaf Oil of Securidaca longependuculata Fers

Nigeria is blessed with a diversity of flora, most of which has remained unexploited for their chemical constituents and biological potentials. Securidaca longepedunculata Fers. (Polygalaceae) is commonly used as a medicine in many parts of Africa. In Nigeria, the plant is commonly employed for the treatment of inflammatory conditions and as purgative. An oral administration of a decoction of the root has been shown to produce a sedative effect, mainly attributed to its content of oleanolic acid glycoside (1). Extracts of the plants from Nigeria has been reported to possess both gastrointestinal and trypanocidal effects (2,3). Elsewhere considerable antimalarial (4), insecticidal (5) and insect repellent activities (6) have been confirmed for extracts from various parts of the plant. On the chemical point of view, ergonine alkaloids (7) and tannins of the presenegamine skeleton (8) have been characterized from the plant. Two minor bitter principles: β-D-(3, 4-disinapoyl)-fructofuranosyl-α-D-(6-sinapoyl)-glucopyranoside and β-D-(3-disinapoyl)-fructofuranosyl-α-D-(6-sinapoyl)glucopyranoside have been described from the bark extracts (9). The seed oils have an abundant of hydroxydienoic fatty acids and acetotriacylglycerols (10). Previous research works on the volatile oils have been focused on the root. Costa et al. (11) identified methyl 4-hydroxybenzoate (methyl paraben) as the dominant volatile compound of the ether extract of the root oil of the plant. In addition, nine others compounds of the benzoic acid derivatives were also characterized. Lognay et al. (12) reported the occurrence of methyl salicylate and 2-hydroxy6-methoxybenzoic acid methyl ester in S. longepedunculata root bark from Senegal. Later Jayasekara et al. also identified methyl salicylate (2-hydroxy benzoic acid methyl ester) as the principal volatile component in the methanol extract of the root bark of the plant from Ghana (13). Methyl salicylate was also reported by Nebe and coworkers (14), as the dominant compound in the root bark oil of the plant from Burkina Faso. Methyl salicylate was identified as the compound responsible for the fumigant property of the root of the plant (12). To the best of our knowledge, there is no report in the literature on the constituents of the volatile fraction of the leaf of the plant from Nigeria and elsewhere. This paper reports on the compounds identified from the oil of the leaf of S. longependuculata grown in Nigeria.