Clerodane diterpenoids from Pulicaria wightiana

Five clerodane diterpenoids have been isolated from the aerial parts of Pulicaria wightiana along with 3'5,6-trihydroxy-3,4',7-trimethoxyflavone and 2-methyl-5-hydroxy-chroman-4-one. The structures and stereochemistry of the compounds were established from spectral (mainly 1D and 2D NMR) studies. The last two compounds were not reported earlier from this plant. The antibacterial activity of the diterpenoids were studied.     

Sesquiterpene lactones from the endemic Cape Verdean Artemisia gorgonum

Leaves and flowers of Artemisia gorgonum (Asteraceae) collected in Fogo, Cape Verde islands, were phytochemically investigated and resulted in isolation and characterization of three guaianolides 1, 2, 5, and a secoguainolide 4, in addition to eight known guaianolides 6-11 and two known germacranolides 12, 13. Structures were elucidated by 1D and 2D NMR experiments. Careful examination of the ¹³C NMR spectrum led to revision of the structure of a previously described guaianolide from 2 to 3. Most compounds exhibited mild antiplasmodial activities, ridentin (13) being the most interesting with an IC₅₀ of 3.8 ± 0.7 μg ml⁻¹ against Plasmodium falciparum FcB1 and weak cytotoxicity in a vero cell line (IC₅₀ 71.0 ± 3.9 μg ml⁻¹).     

Three types of sesquiterpenes from rhizomes of Atractylodes lancea

Eight sesquiterpenes, including four guaiane-types containing an interesting epoxy unit (1-4), a rare tricyclic carbon skeleton-type (5) and three eudesmane-types (6-8), along with five known compounds, were isolated from rhizomes of Atractylodes lancea. The structures and relative configurations of 1-8 were determined by analysis of spectroscopic data, and the absolute configuration of 8 was assigned by application of the CD technique. Compounds 1, 2 and 4 were evaluated for their cytotoxic effects against P388 and A549 cells, but all were inactive. Possible biosynthetic pathways for sesquiterpenes (1-8) were discussed.     

Variations in lipophilic and vacuolar flavonoids among European Pulicaria species

Four European Pulicaria species, P. odora, P. paludosa, P. sicula and P. vulgare, were analysed for their surface and vacuolar constituents for comparison with previous data obtained for P. dysenterica. Each species had a distinct flavonoid pattern with notable differences between leaf and inflorescence. 6-Hydroxyflavonols were the major lipophilic components in all of the species and tissues except in the leaves of P. paludosa and P. vulgare, where scutellarein 6-methyl ether was the main constituent. In the leaves of P. sicula a more unusual flavone, 6-hydroxyluteolin 5,6,7,3',4'-pentamethyl ether, was a major component. Pulicaria odora was distinguished by the presence of a series of methylated 6-hydroxykaempferol derivatives including a 3,5,6,7,4'-pentamethyl ether. Quercetagetin hexamethyl ether occurred in both tissues of P. sicula together with the 3,7,3,4'-tetra methyl ether and other quercetagetin derivatives, which were 5-methylated. Quercetagetin 3,7,3'-methyl ether was present in all species except P. odora. Flavonol glucuronides were characteristic vacuolar constituents of all the taxa studied. Two rare glycosides, patuletin and 6-hydroxykaempferol 6-methyl ether 7-glucuronides were identified in the inflorescence of P. odora. Pulicaria vulgaris, a rare plant of southern England, had the vacuolar flavonoid profile most similar to the other more abundant British plant, P. dysenterica.     

Rare trisubstituted sesquiterpenes daucanes from the wild Daucus carota

Phytochemical and biological investigation of the roots of the wild Daucus carota ssp. carota afforded three new and four known compounds, including four sesquiterpenes daucane esters (1-3 [new], and 4), one polyacetylene (5), one sesquiterpene coumarin (6), and sitosterol glucoside. The structures of the new compounds were determined by comprehensive NMR studies, including DEPT, COSY, NOESY, HMQC and HMBC analyses. Based on an agar diffusion assay, 1, 2 and 4-6 were screened and found to contain a range of low antibacterial activities against four gram positive (Staphylococcus aureus, Streptomyces scabies, Bacillus subtilus, Bacillus cereus) and two gram negative species (Pseudomonas aeruginosa, Escherichia coli) as well as antifungal against Fusarium oxysporum and Aspergillus niger using cup agar diffusion assay.     

NMR characterization of the structure of a beta-(1-->3)-D-glucan isolate from cultured fruit bodies of Sparassis crispa

SCG, a purified beta-d-glucan, obtained from Sparassis crispa, exhibits various biological activities including an antitumor effect, enhancement of the hematopoietic response in cyclophosphamide-induced leukopenic mice, and induction of the production of cytokines. The mechanisms of these effects have been extensively investigated; however, an unambiguous structural characterization of SCG is yet to be achieved. It is well accepted that the biological effects of beta-glucan depend on its primary structures, conformation, and molecular weight. In the present study, we examine the difference of biological effects among beta-glucans, elucidate the primary structure of SCG, and compare with SPG from Schizophyllum commune using NMR spectroscopy. Our data reveal that SCG but not SPG induce cytokine production from bone marrow-derived dendritic cells (BMDCs) and their major structural units are a beta-(1-->3)-d-glucan backbone with single beta-(1-->6)-d-glucosyl side branching units every three residues.     

Structural analysis of water-soluble glucans from the root of Angelica sinensis (Oliv.) Diels

Two water-soluble glucans (designated APS-1cI and APS-1cII) were extracted from the roots of Angelica sinensis (Oliv.) Diels and further purified by anion-exchange and gel-filtration chromatography. Their molecular weights were determined to be 1.7 x 10(5) and 3.9 x 10(4)Da, respectively. The structures of the purified glucans were investigated by a combination of chemical and instrumental analysis, such as methylation analysis, periodate oxidation, GC-MS, as well as FTIR and NMR spectroscopy ((1)H, (13)C, H-H COSY, HSQC, HMBC, TOCSY and NOESY). The data obtained indicated that APS-1cI was a linear alpha-glucan composed of only (1-->6)-alpha-D-Glcp, and APS-1cII had a repeating unit consisting of (1-->4)-alpha-D-Glcp and (1-->6)-alpha-D-Glcp in a molar ratio of 4:1. Such glucans isolated from A. sinensis (Oliv.) Diels have not been previously reported.     

Selection and micropropagation of nodulating and non-nodulating clones ofAlnus crispa (Ait.) Pursh

Summary 600,000 seedlings ofAlnus crispa were inoculated with a 111 mixture of theFrankia strains ACN1 ^AG , AGN1 _exo ^AG and MGP10i. After 3 successive inoculations and screenings, one individual, AC-4, was selected as non-nodulating (Nod^–) with Frankiae. This selected individual AC-4 (Nod^–) and two other clones ofA. crispa, AC-2 and AC-5, known for their ability to nodulate (Nod⁺) and two other clones ofA. crispa, AC-2 and AC-5, known for their ability to nodulate (Nod⁺) withFrankia werein vitro propagated. The different clones ofA. crispa in culture required different kinds and concentrations of sugar during the in vitro multiplication and rooting stages. Nodulation tests using 7Frankia strains indicated that the clone AC-4 (Nod^–) was non-nodulating with 6 of the 7Frankia strains tested. One strain,Frankia ANNI, isolated from one unique nodule produced on the mother-plant AC-4, induced 38% of the AC-4 plantlets to nodulate but with a number of nodules 10 to 20 times less than the clones AC-2 (Nod⁺) and AC-5 (Nod⁺). Morphological observations of the roots of AC-4 (Nod^–) indicated that this clone had few and abnormally short root hairs.     

Elemanolide sesquiterpenes and eudesmane sesquiterpene glycosides from Centaurea hierapolitana

Two elemanolide sesquiterpenes and two eudesmane-type sesquiterpene glycosides named hierapolitanins A-D, were isolated, together with five known compounds, two flavones; hispidulin and jaceosidin, a flavon-C-glycoside, shaftoside, a flavonol glycoside, kaempferol-3-O-rutinoside and a neolignan, dehydrodiconiferyl alcohol from the aerial parts of Centaurea hierapolitana Boiss. (Asteraceae). Structure elucidations were based on spectroscopic evidence.     

Guaiane sesquiterpenes from Amoora rohituka

The petroleum ether extract of the stem bark of Amoora rohituka afforded two novel guaiane-derived sesquiterpenoids, 6beta,7beta-epoxyguai-4-en-3-one (1) and 6beta,7beta-epoxy-4beta,5-dihydroxyguaiane (2). The structures of 1 and 2 were determined by extensive NMR and MS analyses and by comparison of their spectral data with related compounds. The relative stereochemistry of the asymmetric centers in 1 and 2, except at C-5 of 2, were determined by selective 1D-NOESY experiments.     

In vitro anti-influenza virus activity of a cardiotonic glycoside from Adenium obesum (Forssk.)

Methanolic extracts of six Saudi plants were screened for their in vitro antiviral activity using influenza virus A/PR/8/34 (H1N1) and MDCK cells in an MTT assay. The results indicated that the extracts of Adeniumobesum and Tephorosianubica possessed antiviral activity (99.3 and 93.3% inhibition at the concentration of 10 μg/ml, respectively). Based on these results A. obesum was selected for further study by applying bioactivity-guided fractionation to isolate its antiviral principle. The antiviral principle was isolated from the chloroform fraction through solvent fractionation, combined open liquid chromatography and HPLC. The isolated active compound A was identified as oleandrigenin-β-d-glucosyl (1 → 4)-β-d-digitalose, on the basis of its spectral analysis (MS, 1D and 2D NMR). The isolated glycoside showed reduction of virus titre by 69.3% inhibition at concentration of 1 μg/ml (IC₅₀ = 0.86 μg/ml).     

Chemical Composition and Antimicrobial Activity of Essential Oils from the Aerial Parts of Asteriscus graveolens (Forssk.) Less. and Pulicaria incisa (Lam.) DC.: Two Asteraceae Herbs Growing Wild in the Hoggar

In recent years, antimicrobial activities of essential oils have been intensively explored, mainly in researching and developing new antimicrobial agents to overcome microbial resistance. The present study investigates the chemical composition and antimicrobial activities of essential oils obtained from two Asteraceae: Asteriscus graveolens (Forssk .) Less . and Pulicaria incisa (Lam .) DC. Chemical analysis was performed using a combination of capillary GC‐FID and GC/MS analytical techniques. The major component of Asteriscus graveolens were cis‐chrysanthenyl acetate (31.1%), myrtenyl acetate (15.1%), and kessane (11.5%), while for Pulicaria incisa the main components were chrysanthenone (45.3%) and 2,6‐dimethylphenol (12.6%). The oils obtained from the aerial parts were tested against sixteen microbial strains by agar well diffusion technique and dilution methods and showed minimum inhibitory concentrations (MIC) in the range of 19 – 1250 μg/ml. A good antibacterial activity against a common nosocomial pathogen, Acinetobacter baumanniiATCC 19606 was observed, especially from Pulicaria incisa essential oil, with a MIC value up to 19 μg/ml. These results give significant information about the pharmacological activity of these essential oils, which suggest their benefits to human health, having the potential to be used for medical purposes.     

Four illudane sesquiterpenes from Coprinopsis episcopalis

Four new illudane derivatives with antibiotic and cytotoxic properties, illudins I (1), I(2) (2), J (3) and J(2) (4), have been isolated from the fungus Coprinopsis episcopalis (syn. Coprinus episcopalis). These sesquiterpenes are stereoisomers, and their relative structures have been determined taking into consideration 2D NMR data.     

Salinity tolerance of Avicennia marina (Forssk.) Vierh. from Gujarat coasts of India

Greenhouse experiments were conducted to assess the effects of soil salinity on emergence, growth, water status, proline content and mineral accumulation of seedlings of Avicennia marina (Forssk.) Vierh. NaCl was added to the soil and salinity was maintained at 0.2, 2.5, 5.1, 7.7, 10.3, 12.6, 15.4, 17.9, 20.5, 23.0, 25.6 and 28.2 psu. A negative relationship between seedling emergence and salt concentration was obtained. Nevertheless, this mangrove is highly salt tolerant during germination. Growth of seedlings was significantly promoted by low salinity and optimum growth was obtained at 15.4 psu. Higher salinities inhibited plant growth. Growth and dry matter accumulation in tissues followed the same optimum curve. Water potential of tissues became significantly more negative with increasing salinity, and proline content significantly increased. Moreover, water potential and proline content of tissues displayed an S-curve with the inflection point below ∼10 psu. The concentration of Na in tissues increased significantly, whereas K, Ca, Mg, N and P content decreased.     

Antileishmanial activity of a guaianolide from Tanacetum parthenium (L.) Schultz Bip

Leishmaniasis is one of the major infectious diseases affecting the poorest regions of the world. The present study evaluated the antileishmanial activity of a guaianolide purified from the hydroalcoholic extract of aerial parts of Tanacetum parthenium (L.) Schultz Bip. The isolated compound showed activity against the promastigote form of Leishmania amazonensis, with 50% inhibition (IC₅₀) of cell growth at a concentration of 2.6 μg/ml. For the intracellular amastigote form, this guaianolide reduced by 10% the survival index of parasites in macrophages when it was used at 20.0 μg/ml. The selective index (SI) ratio (CC₅₀ for J774G8 cells/IC₅₀ for protozoans) was 385, showing that it is more selective against the parasite than mammalian cells. Morphological alterations of protozoans treated with IC₅₀ included changes in size, shape, and structure (more than one nucleus and flagellum) under both light and scanning electron microscopies.     

Cytotoxic sesquiterpenes from Ligularia platyglossa

Four sesquiterpene lactones including an eremophilenolide dimer, named as biligulaplenolide, 1, 8beta-hydroxy-1-oxo-(14alpha,15alpha eremophil-7(11),9(10)-dien-12,8alpha-olide, 2, 1-hydroxy-2-oxo-(14alpha,15alpha eremophil-1(10),7(11),8(9)-trien-12,8-olide, 3, 4alpha,8beta,9alpha-trihydroxy- 5alphaEta-7(11)-eudesmen-12,8alpha-olide, 4, along with two known ones, 10alpha-hydroxy-1-oxo-eremophil-7(11),8(9)-dien-12,8-olide, 5, and furanoeremophil-1(10)-ene-2,9-dione, 6, were isolated from the underground organs of Ligularia platyglossa (Franch.) Hand.-Mazz. Their structures were elucidated by spectroscopic methods including single-crystal X-ray diffraction analysis (2 and 3). Their in vitro cytotoxicities against seven cancer cell lines (BGC-823, A549, HL-60, B16, SMMC-7721, BEL7402, Hela) were evaluated. Compounds 2, 3, 5 showed cytotoxic activities on HL-60 cancer cells with IC50 in the range of 24.0 to 51.1 microM, whereas compound 3 exhibited only weak cytotoxic activity against the B16, BEL7402 and Hela cancer cells. Flow cytometric analysis indicated that compound 3 induces Hela cells to apoptotic death after 48 h treatment with 0.38 mM of this compound.     

Strobilols A-D: four cadinane-type sesquiterpenes from the edible mushroom Strobilurus ohshimae

Four sesquiterpenoids--strobilols A (1), B (2), C (3), and D (4)--were isolated from the organic extracts of fruiting bodies of the edible mushroom Strobilurus ohshimae. Their structures were determined by spectroscopic methods. Compound 1 exhibited moderate activity against the brine shrimp Artemia salina. This paper is the first report on isolation of cadinane-type sesquiterpenoids from S. ohshimae.     

Cloning and expression of sesquiterpene synthase genes from lettuce (Lactuca sativa L.)

Sesquiterpenoid lactones (SLs) from lettuce (Lactuca sativa L.) include constitutive components of latex such as lactucin and the induced phytoalexin, lettucenin A. A redundant primer strategy was used to recover two full length cDNA clones (LTC1 and LTC2) encoding sesquiterpene synthases from a cDNA library derived from seedlings with the red spot disorder, which accumulate phytoalexins. Recombinant enzymes produced from LTC1 and LTC2 in Escherichia coli catalysed the cyclisation of farnesyl diphosphate to germacrene A, potentially an early step in the biosynthesis of SLs. RT-PCR analysis showed LTC1 and LTC2 were expressed constitutively in roots, hypocotyls and true leaves but not in cotyledons. Expression in cotyledons was induced by challenge with the downy mildew pathogen Bremia lactucae in the disease resistant cultivar Diana. Southern hybridisation experiments showed that LTC1 and LTC2 were not part of a multigene family. The germacrene A synthases provide targets for modified expression to generate beneficial modifications to the SL profile in lettuce.     

Chromenes from Peperomia serpens (Sw.) Loudon (Piperaceae)

Chromatographic separation of the CH2Cl2 extract from leaves of Peperomia serpens yielded two chromenes [5-hydroxy-8-(3',7'-dimethylocta-2',6'-dienyl)-2,2,7-trimethyl-2H-1-chromene (1) and 5-hydroxy-8-(3'-methyl-2'-butenyl)-2,2,7-trimethyl-2H-1-chromene-6-carboxylic acid (2)], besides the known chromene [methyl 5-hydroxy-2,2,7-trimethyl-2H-1-chromene-6-carboxylate (3)] and the flavonoid, dihydrooroxylin (4). Their structural elucidation were achieved by spectroscopic analyses. The antifungal activities of the CH2Cl2 extract and the isolated chromenes were measured bioautographically against Cladosporium cladosporioides and C. sphaerospermum, when it was found that the crude extract showed higher activity as compared to the pure compounds.