Antimycobacterial flavonoids from Derris indica

Flavonoids (1-4), together with ten known compounds (5-14) were isolated from the stems and roots of the mangrove plant Derris indica. Their chemical structures were elucidated by analysis of their spectroscopic data. All compounds except compounds 2 and 6 exhibited antimycobacterial activity with minimum inhibitory concentrations (MIC) between 6.25 and 200 microg/mL.     

Potent inhibition of bacterial neuraminidase activity by pterocarpans isolated from the roots of Lespedeza bicolor

Bacterial neuraminidase has been highlighted as a key enzyme for pathogenic infection and sepsis. Six pterocarpans displaying significant levels of neuraminidase inhibitory activity were isolated from the root bark of Lespedeza bicolor. The isolated compounds were identified as three new pterocarpans (1-3) together with known compounds erythrabyssin II (4), lespebuergine G4 (5), and 1-methoxyerythrabyssin II (6). The new compounds were characterized as bicolosin A (1), bicolosin B (2), and bicolosin C (3). All compounds inhibited bacterial neuraminidase in a dose-dependent manner with significant inhibition (IC(50)=0.09-3.25 μM). All neuraminidase inhibitors screened were found to exhibit noncompetitive kinetics. The three most potent neuraminidase inhibitors (1, 3 and 6) feature a methoxy substitution on C-1.     

Labdane diterpenes from Marrubium velutinum and Marrubium cylleneum

From the aerial parts of Marrubium velutinum and Marrubium cylleneum, seven labdane diterpenes, velutine A, 15-epi-velutine A, velutine B, 15-epi-velutine B, velutine C, cyllenine A and 15-epi-cyllenine A, have been isolated together with five known diterpenes and four known flavones. The structures of the isolated compounds were established by means of NMR [(1)H-(1)H-COSY, (1)H-(13)C-HMQC, HMBC, HMQC-TOCSY, NOESY] and MS spectral analyses. Complete NMR assignments are reported for known compounds.     

Acylated pregnane glycosides from Caralluma tuberculata and their antiparasitic activity

Five pregnane glycosides were isolated from Caralluma tuberculata (1-5), in addition to a known one (russelioside E, 6). The structures of the isolated compounds were elucidated by the analysis of NMR data and FAB-MS experiments. All the isolated compounds were tested for their antimalarial and antitrypanosomal activities as well as their cytotoxicity against human diploid embryonic cell line (MRC5).     

Furanoflavonoids from Pongamia pinnata fruits

Fruits of Pongamia pinnata afforded four new furanoflavonoids, pongapinnol A-D (1-4), and a new coumestan, pongacoumestan (5) along with thirteen known compounds 6-18. Compounds 16 and 17 are isolated for the first time from this plant. The structures of isolated compounds were elucidated on the basis of spectroscopic data interpretation.     

Alpha-pinene-type monoterpenes and other constituents from Artemisia suksdorfii

Two alpha-pinene-type monoterpenes, 7-hydroxymyrtenol (1) and 7-hydroxymyrtenal (2), a inositol derivative, (+)-quebrachitol (3) and two p-menthene triols (4 and 5), in addition to two known compounds were isolated from the aerial parts of Artemisia suksdorfii. The structures of the isolated compounds were established by analysis of spectroscopic data (IR, HR-MS, (1)H and (13)C NMR), including high-field 2D NMR techniques ((1)H-(1)H COSY, HMQC, HMBC and NOE) and in case of 3 was confirmed by X-ray analysis.     

Terpenoids and phenol derivatives from Malva silvestris

A sesquiterpene and a tetrahydroxylated acyclic diterpene as well as two known monoterpenes, 6 C(13)nor-terpenes and 11 aromatic compounds were isolated from the water extract of Malva silvestris. The structures of the compounds were determined by spectroscopic NMR and MS analysis. Effects of these compounds on germination and growth of dicotyledon Lactuca sativa L. (lettuce) were studied in the 10(-4)-10(-7)M concentration range.     

Antimicrobial activity of pentacyclic triterpenes isolated from African Combretaceae

Four pentacyclic tritepenes were isolated from Combretum imberbe Engl. & Diels, of which two are novel glycosidic derivatives of 1alpha,3beta,23-trihydroxyolean-12-en-29-oic acid (hydroxyimberbic acid). Terminalia stuhlmannii Engl. & Diels stem bark yielded two glycosides of hydroxyimberbic acid, one of which is reported for the first time. The structures of the isolated compounds were elucidated by spectroscopic methods. Several of the compounds had antibacterial activity, imberbic acid showing particularly potent activity against Mycobacterium fortuitum and Staphylococcus aureus.     

Cytotoxicity and immunomodulating characteristics of labdane diterpenes from Marrubium cylleneum and Marrubium velutinum

From the aerial parts of Marrubium cylleneum, one labdane nor-diterpene has been isolated together with two labdane diterpenes, hitherto not known as natural products. The structures of the isolated compounds were established by means of NMR [(1)H-(1)H-COSY, (1)H-(13)C-HSQC, HMQC-TOCSY, HMBC, NOESY] and MS spectral analyses. Several diterpenoids from M. cylleneum and M. velutinum were tested for their cytotoxic effect against various cancer cell lines and their immunomodulating potential in human peripheral blood mononuclear cells in standard in vitro assays. Our results show a differential cytotoxicity of some compounds as well as their ability to improve selected lymphocyte functions.     

Triterpenoid saponins from Pteleopsis suberosa stem bark

Thirteen oleanane saponins (1-13), four of which were new compounds (1-4), were isolated from Pteleopsis suberosa Engl. et Diels stem bark (Combretaceae). Their structures were determined by 1D and 2D NMR spectroscopy and ESI-MS spectrometry. The compounds were identified as 2alpha,3beta,19alpha,23,24-pentahydroxy-11-oxo-olean-12-en-28-oic acid 28-O-beta-D-glucopyranosyl ester (1), 2alpha,3beta,19beta,23,24-pentahydroxy-11-oxo-olean-12-en-28-oic acid 28-O-beta-D-glucopyranosyl ester (2), 2alpha,3beta,19alpha,23-tetrahydroxy-11-oxo-olean-12-en-28-oic acid 28-O-beta-D-glucopyranosyl ester (3), and 2alpha,3beta,6beta,19alpha,24-pentahydroxy-11-oxo-olean-12- en-28-oic acid 28-O-beta-D-glucopyranosyl ester (4). The presence of alpha,beta-unsaturated carbonyl function was not common in the oleanane class and the aglycons of these compounds were not found previously in the literature. Moreover, the isolated compounds were tested against Helicobacter pylori standard and vacA, and cagA clinical virulence genotypes. Results showed that compound 6 has an anti-H. pylori activity against three metronidazole-resistant strains (Ci 1 cagA, Ci 2 vacA, and Ci 3).     

Phenolic compounds from the fruit of Garcinia dulcis

Dulcinoside (1), dulcisisoflavone (2), dulcisxanthone A (3) and sphaerobioside acetate (6) together with 22 known compounds were isolated from the green fruit of G. dulcis. Dulcisflavan (4), dulcisxanthone B (5) and isonormangostin (7) together with 22 known compounds were isolated from the ripe fruit. Compounds 6 and 7 were synthetic known compounds. Their structures were determined by spectroscopic methods. The radical scavenging and antibacterial activities of some of the compounds were investigated.     

Further constituents from Caralluma negevensis

Two new megastigmane glycosides (1 and 2) and two new flavone glycosides (3 and 4) were isolated from the methanol extract of the whole plant of Caralluma negevensis Zohary (Asclepiadaceae). The structures of the isolated compounds were characterized as (9R)-2beta,9-dihydroxymegastigma-4,7-dien-3-one-9-O-alpha-L-rhamnopyranosyl-(1-->6)-beta-D-glucopyranoside (1), 2beta,9-dihydroxymegastigma-4-en-3-one 9-O-alpha-L-rhamnopyranosyl-(1-->6)-beta-D-glucopyranoside (2), luteolin 3'-O-beta-D-glucopyranoside-4'-O-alpha-L-rhamnopyranosyl-(1-->2)-beta-D-glucopyranoside (3), and luteolin 3',4'-di-O-beta-D-glucopyranoside (4). The structures of the isolated compounds were established on the basis of spectral evidence and chemical transformation.     

Stilbenes from the roots of Pleuropterus ciliinervis and their antioxidant activities

Two stilbene glycosides, pieceid-2"-O-gallate and pieceid-2"-O-coumarate, were isolated from the MeOH extract of the roots of Pleuropterus ciliinervis Nakai (Polygonaceae), together with two known compounds, resveratrol and pieceid. Their structures were determined spectroscopically, particularly by 2D NMR spectroscopic analysis. The antioxidant activities of stilbenes isolated were determined in vitro against 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals, superoxide radicals and by determining their lipid peroxidation inhibitory activities. Among the compounds isolated, pieceid-2"-O-gallate had the most potent inhibitory scavenging effect on DPPH, superoxide radicals and upon lipid peroxidation inhibition with IC50 values of 16.5, 23.9 and 5.1 microM, respectively.     

Sablacaurin A and B, two 19-nor-3,4-seco-lanostane-type triterpenoids from Sabal causiarum and Sabal blackburniana, respectively

In search for bioactive compounds from Sabal species, sablacaurin A [25-ethyl,23-methyl-19-nor-24-methylene-3,4-seco-4(28)-lanosten-10,3-olide] and sablacaurin B [24-ethyl,24-methyl-19-nor-3,4-seco-4(28),25(26)-lanostadiene-10,3-olide], the first 19-nor lanostane derivatives of the 3,4-seco type with a spiro element, have been isolated from the leaves of Sabal causiarum and Sabal blackburniana respectively, together with the known squalene (S. blackburniana) and ss-sitosterol (S. causiarum). From leaves of Sabal peregrina, the known triterpenes 3-oxo-24-methylenecycloartane and 24-methylcycloart-25(26)-en-3-one were isolated. The structures of these compounds were established from spectroscopic studies.     

Coumaroyl triterpene lactone, phenolic and naphthalene glycoside from stem bark of Diospyros angustifolia

From the ethanolic extract of stem bark of D. angustifolia three new compounds, a coumaroyl triterpene lactone, diospyrosooleanolide (1), a phenolic glycoside, diospyrososide (2) and a naphthalene glycoside, diospyrosonaphthoside (3) were isolated along with five known compounds (4-8). The structures of these compounds were established on the basis of spectroscopic and chemical evidences.     

海南大风子活性成分研究

用色谱技术对海南大风子(Hydnocarpus hainanensis (Merr.) Sleum.)枝条的乙醇提取物进行分离纯化,从中分离得到了6个化合物,经波谱数据分析与文献数据对照,分别鉴定为eoniferaldehyde (1)、mulberroside C(2)、mulberrofuran G(3)、mulb...     

Leishmanicidal cycloartane-type triterpene glycosides from Astragalus oleifolius

Two new cycloartane-type glycosides oleifoliosides A (1) and B (2) were isolated from the lower stem parts of Astragalus oleifolius. Their structures were identified as 3-O-[beta-xylopyranosyl-(1 --> 2)-alpha-arabinopyranosyl]-6-O-beta-xylopyranosyl-3beta,6alpha,16beta,24(S),25-pentahydroxycycloartane and 3-O-[beta-xylopyranosyl-(1 --> 2)-alpha-arabinopyranosyl]-6-O-beta-glucopyranosyl-3beta,6alpha,16beta,24(S),25-pentahydroxycycloartane, respectively, by means of spectroscopic methods (IR, 1D and 2D NMR, ESI-MS). Three known cycloartane glycosides cyclocanthoside E (3), astragaloside II (4) and astragaloside IV (5) were also isolated and characterized. All five compounds were evaluated for in vitro trypanocidal, leishmanicidal and antiplasmodial activities as well as their cytotoxic potential on primary mammalian (L6) cells. Except for the compound 5, all compounds showed notable growth inhibitory activity against Leishmania donovani with IC50 values ranging from 13.2 to 21.3 microg/ml. Only weak activity against Trypanosoma brucei rhodesiense was observed with the known compounds astragaloside II (4, IC50 66.6 microg/ml) and cyclocanthoside E (3, IC50 85.2 microg/ml), while all compounds were inactive against Trypanosoma cruzi and Plasmodium falciparum. None of the compounds were toxic to mammalian cells (IC50's > 90 microg/ml). This is the first report of leishmanicidal and trypanocidal activity of cycloartane-type triterpene glycosides.     

3-Keto steroids from the marine organisms Dendrophyllia cornigera and Cymodocea nodosa

The new (20R)-22E-cholesta-4,22-diene-3,6-dione (1), along with three known 3-keto steroids were isolated from the deep-water Mediterranean scleractinian coral Dendrophyllia cornigera (2-4). Moreover, four known related 3-keto steroids were isolated from the sea grass Cymodocea nodosa (5-8). The structure elucidation of steroid 1 and the full NMR resonance assignments of all isolated metabolites were based on interpretation of their spectral data. All compounds are reported for the first time as metabolites of the investigated organisms. Compounds 2 and 3 showed significant cytotoxicity against lung cancer NSCLC-N6 cell line.     

Neolignan and flavonoid glycosides in Juniperus communis var. depressa

Two neolignan glycosides (junipercomnosides A and B) were isolated from aerial parts of Juniperus communis var. depressa along with two known neolignan glycosides and seven flavonoid glycosides. The structures of the isolated compounds were determined by spectral analysis, in particular by 2D-NMR analysis. The significance of distribution of flavonoids in the chemotaxonomy of genus Juniperus was also discussed.     

Antioxidant phenolic and quinonemethide triterpenes from Cheiloclinium cognatum

The triterpenes, 22beta-hydroxypristimerin and cognatine, were isolated together with the known compounds pristimerin, maytenin, 20alpha-hydroxymaytenin, 22beta-hydroxymaytenin, netzahualcoyol, netzahualcoyondiol and netzahualcoyone from root bark of Cheiloclinium cognatum. The structures of the isolated compounds were elucidated by interpretation of their spectral data, including gHMQC and gHMBC experiments.The isolates were investigated for their radical scavenging abilities through a spectrophotometric assay involving reduction of 2,2-diphenyl-picryl hydrazyl (DPPH).