Sesquiterpenoids from Artemisia gilvescens and an anti-MRSA compound

A new secoguaianolide sesquiterpene (1) was isolated along with its three stereoisomers (2-4) from the nonmedicinal plant Artemisia gilvescens. The structure of 1 was elucidated to be (4S,5S)-dihydro-5-[(1R,2S)-2-hydroxy-2-methyl-5-oxo-3-cyclopenten-1-yl]-3-methylene-4-(3-oxobutyl)-2(3H)-furanone on the basis of 2D NMR and other spectroscopic evidence. Five known sesquiterpenoids were also isolated from this plant, and one of them (5) showed activity against methicillin-resistant Staphylococcus aureus (MRSA).     

New cytotoxic constituents from the Formosan soft corals Clavularia viridis and Clavularia violacea

Three new cytotoxic prostanoids, claviridenone E-G (1-3), and three new cytotoxic steroids, stoloniferone E-G (4-6), were isolated from the methylene chloride solubles of the Formosan soft coral Clavulariaviridis. A cytotoxic cembranoid, claviolide (7), was isolated from the methylene chloride solubles of the Formosan soft coral Clavularia violacea. The structures were elucidated by 1D and 2D NMR spectral analysis, and their cytotoxicity against selected cancer cells was measured in vitro.     

Antimicrobial prenylated anthracene derivatives from the leaves of Harungana madagascariensis

Three new prenylated anthranoids, harunmadagascarins C (1) and D (2) and kenganthranol D (3), together with three known compounds (4-6) were isolated from the leaves of Harungana madagascariensis. Their structures were assigned by spectroscopic methods and by comparison with literature data. In the three new natural products 1-3, one or two prenyl groups are incorporated in furan, pyran, or cyclohexane rings in four different modes of annulation. Compounds 2, 4, and 6 were strongly active against the Gram-positive Bacillus megaterium.     

The antibacterial ent-eusynstyelamide B and eusynstyelamides D, E, and F from the Arctic bryozoan Tegella cf. spitzbergensis

The brominated tryptophan-derived ent-eusynstyelamide B (1) and three new derivatives, eusynstyelamides D, E, and F (2-4), were isolated from the Arctic bryozoan Tegella cf. spitzbergensis. The structures were elucidated by spectroscopic methods including 1D and 2D NMR and analysis of mass spectrometric data. The enantiomer of 1, eusynstyelamide B, has previously been isolated from the Australian ascidian Eusynstyela latericius. Antimicrobial activities are here reported for 1-4, with minimum inhibitory concentrations (MIC) as low as 6.25 μg/mL for 1 and 4 against Staphylococcus aureus. Eusynstyelamides 2 and 3 showed weak cytotoxic activity against the human melanoma A 2058 cell line.     

西藏产全缘叶绿绒蒿的化学成分研究

目的:对藏药材全缘叶绿绒蒿(Meconopsis integrifolia Franch.)的化学成分进行分离纯化和结构鉴定。方法:采用正反相硅胶柱色谱和Sephadex LH-20凝胶柱色谱方法进行分离纯化,NMR和MS等波谱方法进行结构鉴定。结果:从青海产藏药全缘叶绿绒蒿地上部分甲醇提取物中分离得到8个化合物:去甲血根碱(norsanguinarine)①,β-谷甾醇(β-sitosterol)②;3-羟基-奇墩果烷-12(13)-烯-30-酸(3-hydroxyolean-12(13)-en-24-oic acid)③;6-丙酮基-5,6-二氢血根碱(6-acetonyl-5,6-dihydrosanguinarine)④;木犀草素(1uteolin)⑤;胡萝卜苷(daucosterol)⑥;quercetin 3-O-β-D-glucopyranosyl-(1→0)-β-D-glucopyranoside⑦;普托品(protopine)⑧。结果:化合物1,4和7为首次从该种植物中分离得到。     

Bioactive diterpenes and other constituents of Croton steenkampianus

A new indanone derivative (1) and two new diterpenoids (2 and 3), together with three known flavonoids, have been isolated from an ethanol extract of the leaves of Croton steenkampianus. The structure of 2 was solved by single-crystal X-ray diffraction analysis, whereas those of 1 and 3 were established mainly by 1D and 2D NMR spectroscopic methods. The isolated compounds were tested for their antiplasmodial activity and cytotoxicity. Antiplasmodial assays against chloroquine-susceptible strains (D10 and D6) and the chloroquine-resistant strains (Dd2 and W2) of Plasmodium falciparum showed that compound 2 gave moderate activities at 9.1-15.8 μM, while none of the compounds were cytotoxic against Vero cells.     

Three new sesquiterpenes from roots of Curcuma longa

Objective: To study the chemical constituents from the roots of Curcuma longa. Methods: The structures of the new compounds were elucidated based on extensive spectral analysis, including 1D and 2D NMR, MS, UV, and CD analysis. Results: Two new sesquiterpene compounds (1S,2R,5R,7S,8R)-2,8-epoxy-5-hydroxybisabola-3,10-dioen-9-one (1), (1R,2R,5R,7S,8R)-2,8-epoxy-5-hydroxybisabola-3,10-dioen-9-one (2), and a new natural product 6-(4-Hydroxymethylphenyl)-2-methyl-hept-2-ene-4-one (3) together with three known compounds ar-turmerone (4), 2-methyl-6-(4-hydroxyphenyl-3-methyl)-2-hepten-4-one (5) and 2-methyl-6-(4-hydroxyphenyl)-2-hepten-4-one (6) were isolated from C. longa root extract with 95% ethanol. Conclusion: In the study, three new compounds were isolated from C. longa, and their absolute configurations were determined.     

Three new scalarane-based sesterterpenes from the tropical marine sponge strepsichordaia lendenfeldi1

From the dichloromethane extract of the tropical marine sponge Strepsichordaia lendenfeldi collected from the Great Barrier Reef, Australia, three new (1, 2, and 9) and seven known (3-8 and 10) scalarane-based sesterterpenes were isolated. All molecular structures were secured by spectroscopic methods, particularly 1D and 2D NMR, and accurate mass measurement.     

Antioxidant chalcone glycosides and flavanones from Maclura (Chlorophora) tinctoria

Four chalcone glycosides (1-4), including three new natural products, and three flavanones (5-7) were isolated from the methanol extract of stem bark of Maclura tinctoria. The new compounds have been characterized as 4'-O-beta-D-(2' '-p-coumaroyl)glucopyranosyl-4,2',3'-trihydroxychalcone (1), 4'-O-beta-D-(2' '-p-coumaroyl-6' '-acetyl)glucopyranosyl-4,2',3'-trihydroxychalcone (2), and 3'-(3-methyl-2-butenyl)-4'-O-beta-D-glucopyranosyl-4,2'-dihydroxychalcone (3); the known derivatives were elucidated as 4'-O-beta-D-(2' '-acetyl-6' '-cinnamoyl)glucopyranosyl-4,2',3'-trihydroxychalcone (4), eriodictyol 7-O-beta-D-glucopyranoside (5), naringenin (6), and naringenin 4'-O-beta-D-glucopyranoside (7). Their structures were determined by 1D and 2D NMR and ESIMS. The antioxidant activity of all the isolated compounds was determined by measuring free-radical-scavenging effects using two different assays, namely, the Trolox Equivalent Antioxidant Capacity (TEAC) assay and the coupled oxidation of beta-carotene and linoleic acid (autoxidation assay). The results showed that compound 3 was the most active in both antioxidant assays.     

Major flavonoids from Arabidopsis thaliana leaves.

The three major flavonoids isolated from Arabidopsis thaliana plants grown in the greenhouse were identified by means of spectroscopic analysis (UV, NMR, MS) and chiral capillary zone electrophoresis as the novel kaempferol 3-O-beta-[beta-D-glucopyranosyl(1-->6)D-glucopyranoside]-7-O-alpha-L- rhamnopyranoside (1), kaempferol 3-O-beta-D-glucopyranoside-7-O-alpha-L-rhamnopyranoside (2), and kaempferol 3-O-alpha-L-rhamnopyranoside-7-O-alpha-L-rhamnopyranoside (3). Comprehensive NMR studies including selective 1D and gradient-enhanced 2D techniques were applied in order to achieve full signal assignment and definitive proof of linkage for compound 1.     

Brominated sesquiterpenes from the red alga Laurencia obtusa

Four new sesquiterpenes, (8R)-8-bromo-10-epi-beta-snyderol (1), (8S)-8-bromo-beta-snyderol (2), 5-bromo-3-(3'-hydroxy-3'-methylpent-4'-enylidene)-2,4,4-trimethylcyclohexanone (3), and the epoxide 4, have been isolated from the chloroform-methanol extract of Laurencia obtusa, together with the three known compounds alpha-snyderol (5), alpha-snyderol acetate (6), and stigmasterol. The structures of the isolated compounds were elucidated through spectroscopic analyses. Compound 1 showed antimalarial activity, with IC(50) values of 2700 and 4000 ng/mL against the D6 and W2 clones of Plasmodium falciparum, respectively.     

Purine alkaloids from the South China Sea gorgonian Subergorgia suberosa

Four new purine alkaloids, namely, 6-(1'-purine-6',8'-dionyl)suberosanone ( 1), 3,9-(2-imino-1-methyl-4-imidazolidinone-5-yl)isopropenylpurine-6,8-dione ( 2), 1-(3'-carbonylbutyl)purine-6,8-dione ( 3), and 9-(3'-carbonylbutyl)purine-6,8-dione ( 4), together with three known compounds, guanosine ( 5), thymidine ( 6), and adenosine ( 7), were isolated from the EtOH/CH 2Cl 2 extracts of the South China Sea gorgonian Subergorgia suberosa. The structures of 1- 4 were determined on the basis of extensive spectroscopic analysis, including 1D and 2D NMR data. Compounds 1- 4 all showed weak cytotoxicity toward human cancer cell lines MDA-MB-231 and A435.     

New biphenyl compounds with DNA strand-scission activity from Clusia paralicola

Three new biphenyl derivatives, clusiparalicolines A (1), B (2), and C (3), were isolated from the roots of Clusia paralicola by bioassay-directed fractionation using the DNA strand-scission and the KB human cancer cell line cytotoxicity assays. Compounds 1 and 2 were found to be active in the DNA strand-scission assay, whereas all three compounds exhibited modest cytotoxicity against the KB cell line. The structures of 1-3 were elucidated by spectroscopic methods including 1D and 2D NMR techniques.     

New diketopiperazine metabolites from the sclerotia of Aspergillus ochraceus.

Three new diketopiperazine-containing metabolites 1-3 have been isolated from the sclerotia of Aspergillus ochraceus (NRRL 3519) by chromatography on Sephadex LH-20 and reversed-phase hplc. The structures of these compounds were established using extensive high-field 1D and 2D nmr experiments. All three compounds cause moderate reduction in weight gain in assays against the lepidopteran crop pest Helicoverpa zea.     

Assessment of the antiprotozoal activity of Galphimia glauca and the isolation of new nor-secofriedelanes and nor-friedelanes

Four new terpenoids, comprising three nor-secofriedelanes (1-3) and one nor-friedelane (4), were isolated from Galphimia glauca, together with the known flavonol quercetin and the sterols stigmasterol and sitosterol 3-O-beta-D-glucoside. The structure elucidation of the new isolates was conducted by 1D and 2D NMR techniques. Compounds 1-4 were given the trivial names galphin A, galphin B, galphin C, and galphimidin, respectively. All isolates were tested for in vitro antiprotozoal and cytotoxic activities. Quercetin was the only substance isolated that showed any antiprotozoal activity, and this was weak; the IC(50) values were 14 microM against Plasmodium falciparum K1, 13.2 microM against Trypanosoma brucei brucei, and 63.8 microM against Leishmania donovani. Quercetin was found to be inactive against KB cells (IC(50) = 295.8 microM).     

Cytotoxic diterpenoids and sesquiterpenoids from Pteris multifida

Three new ent-kaurane diterpenoids, named pterokaurane M 1-M 3 ( 1- 3) and three new C 14 pterosin-sesquiterpenoids, named multifidoside A-C ( 4- 6), along with 18 known compounds, were isolated from the whole plants of Pteris multifida . The structures of 1- 6 were established using spectroscopic methods, including extensive 2D NMR and CD analyses. Compounds 4 and 5 showed cytotoxicity against the HepG2 tumor cell line with IC 50 values of less than 10 microM.     

Bioactive lignans from Peperomia heyneana

Four new compounds, including three secolignans (1-3) and one tetrahydrofuran lignan (4), were isolated from the petroleum ether and EtOAc fractions of Peperomia heyneana. These compounds were accompanied by eight known secolignans, one known tetrahydrofuran lignan, one known cyclohexenone, and one known amide. The structures were elucidated mainly by 1D and 2D NMR and MS experiments, and the relative configurations by NOE techniques. Five compounds were evaluated for their inhibitory activities against HIV-1 in infected C8166 cells.     

Antineoplastic agents. 534. isolation and structure of sansevistatins 1 and 2 from the African Sansevieria ehrenbergii

Using bioactivity-directed isolation procedures, three new spirostanol saponins designated sansevierin A (1), sansevistatin 1 (2), and sansevistatin 2 (3) were isolated (10(-5) % yield) from the CH3OH-CH2Cl2 extract of Sansevieria ehrenbergii, accompanied by three known steroidal saponins (4-6). The structures were determined on the basis of chemical methods and spectroscopic analysis, especially 1D and 2D NMR experiments. Each of the saponins was evaluated against the P388 lymphocytic leukemia cell line and a panel of human cancer cell lines. Except for 1, all were found to cause inhibition of cancer cell growth. In addition, most of the saponins exhibited antimicrobial activity, particularly against the pathogenic fungi Candida albicans and Cryptococcus neoformans.     

Oleanane triterpenes from Junellia tridens

Three novel triterpenes, 3,4-seco-olean-12-ene-3,28-dioic acid (4), 3alpha-hydroxyolean-11-en-28,13beta-olide (5), and 3alpha-hydroxyoleane-11:13(18)-dien-28-oic acid (6), were isolated from the aerial parts of the Argentinean shrub, Junellia tridens. Another five compounds-oleanolic (1), oleanonic (2), and epioleanolic acids (3), all biosynthetically related to the three new oleananes, and epibetulinic acid (7) and sitosterol (8)-were also isolated. Structures were elucidated primarily by 1D and 2D NMR and mass spectrometry, and all protons and carbons of the three novel compounds were fully assigned by NMR. We report the minimum inhibitory concentrations of these compounds against Mycobacterium tuberculosis and conclude that they are responsible for antitubercular activity originally observed in the crude plant extract. LC-MS data is provided on the occurrence of triterpenes 1-6 in six other species of Junellia.     

New briaranes from the Taiwanese gorgonian Junceella juncea

In addition to the known junceelolide C (4), three new briaranes, juncenolides B (1), C (2), and D (3), have been isolated from the acetone extract of a red Gorgonian Junceella juncea collected in Taiwan. The structures of 1-3 were elucidated on the basis of FABMS and 2D NMR techniques including COSY, HMQC, HMBC, and NOESY experiments. Among them, compound 2 exhibited mild cytotoxicity against human liver carcinoma (HEPA 59T/VGH) and oral epidermoid (KB) carcinoma cells.