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.     

Phenolics from the culms of five bamboo species in the Tangjiahe and Wolong Giant Panda Reserves,Sichuan, China

Phenolic compounds were studied in the culms of five bamboo species collected in China: Yushania chungii, Fargesia robusta, Fargesia denudata, Fargesia rufa and Fargesia scabrida. All the species are eaten by giant panda (Ailuropoda melanoleuca). The culms contained phenolic acids and flavonoids in small concentrations, except for F. robusta, which did not contain flavonoids in detectable amounts. The species differed from each other in their phenolic composition. For example, F. rufa with the highest number of compounds clearly differed from other species. There were also differences among sampling sites, which reflect the differences among genotypes. Furthermore, there were clear ontogenetic differences in the culms: some compounds were present in mature culms but not in young (1–2 year old) culms, while the concentrations of other compounds decreased with increasing age. Over all, the composition and concentrations of soluble phenolic compounds in the bamboo culms were affected by species, age and site.     

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.     

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.     

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).     

Constituents of Chrysothamnus viscidiflorus

A phytochemical investigation of the aerial parts of Chrysothamnus viscidiflorus var. viscidiflorus afforded three new [chrysothol (1), 2 and 4] and seven known compounds, including five sesquiterpenes, two cinnamic acid derivatives, two ketoalcohol derivatives and one coumarin glucoside. The structures of two previously reported compounds, 1b and 1c, were revised on the basis of chemical reaction. Structures of the compounds were determined by extensive NMR studies, including DEPT, COSY, NOE, HMQC, HMBC and X-ray analysis. The unpublished X-ray data of the known compounds 6 and 7 are reported. Compounds chrysothol (1), and 8-10 showed anti-cancer activity against human breast cancer cells.     

Chemistry and weak antimicrobial activities of phomopsins produced by mangrove endophytic fungus Phomopsis sp. ZSU-H76

Three metabolites named phomopsin A (1), B (2) and C (3), together with two known compounds cytosporone B (4) and C (5), were isolated from the mangrove endophytic fungus, Phomopsis sp. ZSU-H76 obtained from the South China Sea. Their structures were elucidated by spectroscopic methods, mainly by 1D and 2D NMR spectroscopic techniques. The medium-sized cyclic phenol ether based on 1 or 2 is rare in natural products. In bioassays, compounds 1, 2, and 3 had no significant antibiotic activities, but compounds 4 and 5 inhibited two fungi Candida albicans and Fusarium oxysporum with an MIC ranging from 32 to 64 microg/ml.     

Antimicrobial metabolites produced by an intertidal Acremonium furcatum

In a screening for antimicrobial metabolites, amides of D-allo- and L-isoleucine derivatives were isolated from the culture of a marine strain of Acremonium furcatum. Structural elucidation of these compounds was performed by analysis of spectroscopic data and confirmed by synthesis. All of the compounds, natural and synthetic intermediates, were bioassayed against bacteria and phytopathogenic fungi, with many showing remarkable antifungal activities.     

Limonoids from the stems of Toona ciliata var. henryi (Meliaceae)

Ten limonoids, toonacilianins A-J, and two norlimonoids, toonacilianins K and L, together with seven known compounds were isolated from the stems of Toona ciliata var. henryi (Meliaceae). Their structures were elucidated by spectroscopic analysis. Two compounds showed strong cytotoxic activities.     

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.     

Iridoid and phenolic glycosides from Morinda coreia

From the leaves and branches of Morinda coreia, six compounds [yopaaosides A-C, 10-O-acetylmonotropein, 6-O-acetylscandoside and 3,4,5-trimethoxyphenyl 1-O-beta-apiofuranosyl (1"-->6')-beta-glucopyranoside] have been isolated together with five known compounds. Structural elucidations were based on analyses of physical and spectroscopic data.     

Phytotoxic cis-cinnamoyl glucosides from Spiraea thunbergii

Spiraea thunbergii Sieb. was found to contain 1-O-cis-cinnamoyl-beta-D-glucopyranose and 6-O-(4'-hydroxy-2'-methylene-butyroyl)-1-O-cis-cinnamoyl-beta-D-glucopyranose as major plant growth inhibitory constituents along with related compounds of lower phytotoxicity including 6-O-(trans-cinnamoyl)-1-O-(4"-hydroxy-3"-methyl-furan-2"-one)-beta-D-glucopyranose, 6-O-(4'-hydroxy-2'-methylene-butyroyl)-1-O-trans-cinnamoyl-beta-D-glucopyranose, and 1-O-trans-cinnamoyl-beta-D-glucopyranose. The former three compounds were cinnamoyl glucosides.     

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.     

Isolation and structure elucidation of three neo-clerodane diterpenes from Teucrium fruticans L. (LABIATAE)

Recently, the isolation from Teucrium fruticans of neo-clerodanes, namely 7beta-hydroxyfruticolone, 11-hydroxyfruticolone, deacetylfruticolone and 6-acetyl-10-hydroxyteucjaponin B, in addition to fruticolone, isofruticolone and 8beta-hydroxyfruticolone (three out of the four previously reported ones), and 6-acetylteucjaponin B (isolated from T. scordium and T. grisebachii) was reported. Minor compounds presumably of neo-clerodane nature were shown by HPLC analysis on a new extract. Three new compounds, difuranofruticol, deoxyfruticolone and 10-hydroxyteucjaponin B, and the known 7,8-didehydrofruticolone were unambiguously elucidated based on extensive NMR spectral studies (one- and two-dimensional experiments). The compounds were assayed for their antifeedant activity against Spodoptera littoralis and for their antifungal activity against Rhizoctonia solani. Compounds 9-11 showed low antifeedant activity and the feeding ratio of 12 was moderate-low. None of the tested compounds displayed significant activity against R. solani.     

Phenolic dimers and an indole alkaloid from Campylospermum flavum (Ochnaceae)

From the leaves and stem bark of Campylospermum flavum (Ochnaceae), three compounds, namely 4?-O-methylagathisflavone, flavumchalcone, and flavumindole have been isolated together with 10 known compounds, including three flavonoids, two biflavonoids, two alkaloids, two nitrile glucosides, and glucopyranosyl-β-sistosterol. The structures of these compounds and their relative configurations were established by 1D and 2D NMR experiments. The methanolic crude extracts of leaves and stem bark of C. flavum and compounds displayed a significant cytotoxicity towards Artemia salina larvae.     

Insilico analysis and molecular docking of resuscitation promoting factor B (RpfB) protein of Mycobacterium tuberculosis

Invulnerability of Mycobacterium tuberculosis to various drugs and its persistency has stood as a hurdle in the race against eradication of the pathogenecity of the bacteria. Identification of novel antituberculosis compounds is highly demanding as the available drugs are resistant. The ability of the bacteria to surpass the body''s defenses and adapt itself to survive for disease reactivation is contributed by secreted proteins called resuscitating promoting factors (Rpfs). These factors aid in virulence and resuscitation from dormancy of the bacteria. Sequence analysis of RpfB was performed and compounds were first screened for toxicity and high-throughput virtual screening eliminating the toxic compounds. To understand the mechanism of ligand binding and interaction, molecular docking was performed for the compounds passing through the filter resulting with better docking studies predicting the possible binding mode of the inhibitors to the protein. Of all the active residues the binding conformation shows that residues Arg194, Arg196, Glu242, and Asn244 of the RpfB protein play vital role in the enzyme activity and interacts with the ligands. Promising compounds have been identified in the current study, thus holding promise for design of antituberculosis drugs.     

Response of scab-susceptible (McIntosh) and scab-resistant (Liberty) apple tissues to treatment with yeast extract and Venturia inaequalis

Yeast extract and Venturia inaequalis treated intact scab-susceptible (McIntosh) and scab-resistant (Liberty) apple plants and their organs were analyzed for phenolic metabolites. The major phenolic compounds found in both non-treated and treated leaves were phloridzin and phloretin which accumulated in mM concentrations. Untreated and treated stems and roots contained only phloridzin as the major detectable metabolite during the course of the investigation. The accumulation of phloridzin and phloretin was not developmentally regulated, since they were present in both young and old leaves, and also in the intercellular washings of both scab-susceptible and scab-resistant plants. The major metabolites of both McIntosh and Liberty fruits were cinnamyl glucose and p-coumarylquinic acid, which increased 20-fold in Liberty fruit upon yeast extract treatment. The same compounds increased only 2-fold in McIntosh fruits. Minor compounds in the fruits of both cultivars were p-coumaric acid, phloridzin and phloretin, the latter compound being present at the threshold of detection. Biphenyl and dibenzofuran compounds, the major metabolites of elicitor treated Liberty cell suspension cultures, could not be detected in the intact plants. These results indicate differential response of plant organs and cell suspension cultures to elicitor treatment or pathogen invasion.     

ent-Kaurane diterpenoid glycosides from a Malagasy endemic plant,Cussonia vantsilana

Four ent-kaurane diterpenoid glycosides, cussovantosides A-D, were isolated from the dried leaves of Cussonia vantsilana Baker, together with six known compounds. The structures of the compounds were deduced on the basis of their physical and spectral data.     

Glucose-lowering activity of novel tetrasaccharide glyceroglycolipids from the fruits of Cucurbita moschata

Two new tetrasaccharide glyceroglycolipids were obtained from pumpkin. The structures of the two compounds were determined using chemical methods and spectroscopic analysis. Both compounds demonstrated significant glucose-lowering effects in streptozotocin- and high-fat-diet-induced diabetic mice.     

Cytotoxic ent-abietane diterpenes from Gelonium aequoreum

Seventeen ent-abietane diterpenes, including gelomulides K-X (1-14), and three known compounds, were isolated from a dichloromethane-soluble extract of Gelonium aequoreum through bioassay-guided fractionation. Their structures were identified by spectroscopic methods, and stereochemistry was confirmed by X-ray crystallographic analysis, CD spectral data, and Mosher's method. The isolates were evaluated for in vitro cytotoxic activity, and compounds 1 and 3 showed moderate cytotoxicity against lung (A549), breast (MDA-MB-231 and MCF7), and liver (HepG2) cancer cell lines.