Crotonoids A-H, Labdane-Type Diterpenoids with Anti-Inflammatory Activity from Croton sublyratus.

Croton sublyratus (Euphorbiaceae) is a traditional medicinal plant used by the Thai populace to treat helminthic infections and dermatologic conditions. In present study, eight new labdane-type diterpenoids, crotonoids A-H (1-8) and one known analogue (9) were isolated from the aerial parts of C. sublyratus. Compounds 6 and 7 belong to the rare class of 14,15-dinor-labdane diterpenoids. Compound 8 exhibited a rare 14,15,17-trinor-labdane skeleton. The structures of all these diterpenoids were elucidated by spectroscopic data analysis, electronic circular dichroism calculations, and single-crystal X-ray diffraction analysis. Compound 9 exhibited moderate anti-inflammatory activity via the inhibition of NO production in lipopolysaccharide-induced RAW 264.7 cells.

Sumatranins A-J: Lignans with Immunosuppressive Activity from Cleistanthus sumatranus.

Chemical investigation of the twigs of Cleistanthus sumatranus (Phyllanthaceae) led to the isolation of 10 undescribed lignans, sumatranins A-J (1-10). Compounds 1-4 are unprecedented furopyran lignans characterized by a unique 2,3,3a,9a-tetrahydro-4H-furo[2,3-b]chromene heterotricyclic framework. Compounds 9 and 10 are rare 9'-nor-dibenzylbutane lignans. Structures were established based on analyses of spectroscopic data, X-ray crystallographic data, and experimental ECD spectra. Immunosuppressive assays revealed compounds 3 and 9 displayed moderate inhibitory effects with good selectivity indexes against LPS-induced B lymphocyte proliferation.

Laeviganoids A-T, ent-Clerodane-Type Diterpenoids from Croton laevigatus.

Laeviganoids A-T (1-20), 20 new ent-clerodane-type diterpenoids featuring a 2-furanone (1-3) or a furan (4-20) ring, as well as six analogues (21-26), were isolated from the roots of Croton laevigatus. Their structures were determined by spectroscopic data analysis, experimental electronic circular dichroism measurements, and X-ray crystallographic studies. Compounds 4-6, 16, 21-24, and 26 could influence the anti-inflammatory protumoral phenotype of macrophages. Among these compounds, 21 and 26 are the most potent, as evidenced by consistently downregulating the classic anti-inflammatory cytokine IL-10 and upregulating the classic pro-inflammatory cytokine TNF-α on the secretion level in RAW 264.7 cells.

Densely Functionalized Macrocyclic Sesquiterpene Pyridine Alkaloids from Maytenus austroyunnanensis.

Eleven densely functionalized new dihydro-ß-agarofuran sesquiterpenoid derivatives, named maytenoids A-K (1-11), as well as one known analog, were isolated and characterized from Maytenus austroyunnanensis. Their structures were assigned based on analysis of spectroscopic data and X-ray crystallography. Compounds 1-9 are macrocyclic sesquiterpene pyridine alkaloids generated by the respective acylation of the hydroxy groups at C-3 and C-13 of dihydro-ß-agarofuran sesquiterpenoids via diverse pyridine dicarboxylic acids. Compounds 1, 2, 5-10, and 12 exhibited significant inhibitory effects on NO production at 10 µM in lipopolysaccharide (LPS)-stimulated BV2 cells.

Cephalotane-type C20 diterpenoids from Cephalotaxus fortunei var. alpina.

Seventeen new cephalotane-type diterpenoids, fortalides A-Q (1-17), along with five known analogues, were isolated from the seeds of Cephalotaxus fortunei var. alpina. Their structures were determined by extensive spectroscopic methods, as well as electronic circular dichroism (ECD) and X-ray crystallographic data analyses. Some isolates exhibited unusual structural features that were first found in cephalotane-type diterpenoids, such as the occurrence of the 7-oxabicyclo[4.1.1]octane moiety in 14 and 15 and the cis-arrangement of 3-OH and Me-19 in 9. Besides, the antiplasmodial activity of these compounds was evaluated in this study.

Spicatulides A-G, Phenolic-Monoterpenoid Hybrids from Chloranthus spicatus.

Spicatulides A-G (1-7), seven new phenolic-monoterpenoid hybrid molecules, along with two known compounds, 8 and 9, were isolated and identified from Chloranthus spicatus. Compound 1 represents an unprecedented skeleton featuring an aryl-fused 2-oxabicyclo[4.3.1]decane moiety, and compound 2 is the first example of a denudaquinol-normonoterpenoid adduct. Their structures with absolute configurations were elucidated on the basis of spectroscopic data analyses and TDDFT-ECD calculations. Compounds 3, 5, 6, and 9 exhibited the activity of reducing lipogenesis in HepG2 cells in a dose-dependent manner.

Limonoids from Cipadessa baccifera.

Eighteen new limonoids, including eight methyl angolensates (1-8) and 10 cipadesins (9-18), were isolated from the leaves of Cipadessa baccifera. Their structures were characterized by means of spectroscopic data analyses, single-crystal X-ray diffraction, and quantum chemistry computational methods. The C-6 configurations in those compounds possessing a C-6 hydroxy group were all assigned as S regardless of the magnitude of J5,6, and the C-2' configuration in those bearing a 2-methylbutyryl residue was defined by single-crystal X-ray diffraction and NMR data. Compounds 1, 5, 6, 7, 11, and 12 showed moderate antimalarial activities with IC50 values ranging from 12 to 28 µM.

Structural Elucidation and Total Synthesis of Three 9-Norlignans from Curculigo capitulata.

Capitulactones A-C, three unprecedented 9-norlignans featuring a unique 3,5-dihydrofuro[2,3- d]oxepin-7(2 H)-one scaffold, were isolated from the roots of Curculigo capitulata. Their structures with absolute configurations were unambiguously established by a combination of spectroscopic data, ECD analysis, and total synthesis. Biomimetic total syntheses of three pairs of the corresponding enantiomers were achieved in 9-10 steps with overall yields of 14.8, 12.7, and 10.3%, respectively. Notably, the unique scaffold of the common western hemisphere of the molecules was constructed by using the oxidation-reduction strategy from benzodihydrofuran.

Cytotoxic Tigliane Diterpenoids from Croton damayeshu.

Chemical investigation of an EtOH extract of the twigs and leaves of Croton damayeshu afforded 10 new tigliane diterpenoids, crodamoids A-J (1-10), along with five known compounds. Their structures were elucidated by physical data analysis. Compounds 8, 9, and 15 displayed cytotoxic effects against two human tumor cell lines, A549 and HL-60 (IC50: 0.9-2.4 µM).

17- nor-Cephalotane-Type Diterpenoids from Cephalotaxus fortunei.

Seventeen new 17- nor-cephalotane-type diterpenoids, fortalpinoids A-Q (1-17), were isolated from the seeds of Cephalotaxus fortunei var. alpine. Compound 12 represents the first 17- nor-cephalotane-type diterpenoid featuring an 8-oxabicyclo[3.2.1]oct-2-ene moiety. The absolute configuration of fortunolide A (18) was determined for the first time, and the structure of cephinoid Q was revised to 14- epi-cephafortoid A (24) by X-ray crystallographic data analysis. Some of the compounds showed significant cytotoxicity against A549 and HL-60 cells, and the structure-activity relationship of this compound class is discussed.

Nanomolar Antimalarial Agents against Chloroquine-Resistant Plasmodium falciparum from Medicinal Plants and Their Structure-Activity Relationships.

Inspired by the discovery of the antimalarial drug artemisinin from a traditional Chinese medicine (TCM), a natural product library of 44 lindenane-type sesquiterpenoids was assessed for activities against the Dd2 chloroquine-resistant strain of the malaria parasite Plasmodium falciparum. These compounds were mainly isolated from plants of the Chloranthus genus, many species of which are named "Sikuaiwa" in TCM and have long been used to treat malaria. The compounds consisted of 41 sesquiterpenoid dimers and three monomers, including the 12 new dimers 1-12 isolated from Chloranthus fortunei. The results showed that 16 dimers exhibited potent antiplasmodial activities (<100 nM); in particular, compounds 1, 14, and 19 exhibited low nanomolar activities with IC50 values ranging from 1 to 7 nM, which is comparable to the potency of artemisinin, and selectivity index values toward mammalian cells greater than 500. A comprehensive structure-activity relationship study indicated that three functional groups are essential and two motifs can be modified.

Eucarobustols A-I, Conjugates of Sesquiterpenoids and Acylphloroglucinols from Eucalyptus robusta.

Nine new conjugates of sesquiterpenoids and acylphloroglucinols, named eucarobustols A-I (1-9), as well as 11 known analogues were isolated from the leaves of Eucalyptus robusta. The sesquiterpenoid motifs furnishing the new conjugates included four structural types of aristolane (1 and 2), guaiane (3), eudesmane (4), and aromadendrane (5-9) moieties. Compounds 1 and 2 were found to represent the first examples of conjugates of aristolane and acylphloroglucinol units. In turn, compound 3 features a new coupling model of guaiane and acylphloroglucinol via the C-4-C-7' bond. Compounds 1, 7, and 9 showed inhibitory activities against protein tyrosine phosphatase 1B (PTP1B) with IC50 values of 1.3, 1.8, and 1.6 µM, respectively.

Archaeal communities associated with roots of the common reed (Phragmites australis) in Beijing Cuihu Wetland.

The richness, phylogeny and composition of archaeal community associated with the roots of common reed (Phragmites australis) growing in the Beijing Cuihu Wetland, China was investigated using a 16S rDNA library. In total, 235 individual sequences were collected, and a phylogenetic analysis revealed that 69.4 and 11.5 % of clones were affiliated with the Euryarchaeota and the Crenarchaeota, respectively. In Euryarchaeota, the archaeal community was dominated by species in following genera: Methanobacterium in the order Methanobacteriales (60.7 %); Methanoregula and Methanospirillum in the order Methanomicrobiales (20.2 %), and Methanomethylovorans, Methanosarcina and Methanosaeta in the order Methanosarcinales (17.2 %). Of 27 sequences assigned to uncultured Crenarchaeota, 22 were grouped into Group 1.3, and five grouped into Group 1.1b. Hence, the archaeal communities associated with reed roots are largely involved in methane production, and, to a lesser extent, in ammonia oxidization. Quantification of the archaeal amoA gene indicated that ammonia oxidizing archaea were more numerous in the rhizosphere soil than in the root tissue or surrounding water. A total of 19.1 % of the sequences were unclassified, suggesting that many unidentified archaea are probably involved in the reed wetland ecosystem.

Four new triterpenoids isolated from the resin of Garcinia hanburyi.

Four new triterpenoids, 2-O-acetyl-3-O-(4'-O-acetyl)-α-l-arabinopyranosylmaslinic acid (1), 2-O-acetyl-3-O-(3'-O-acetyl)-α-l-arabinopyranosylmaslinic acid (2), 2-O-acetyl-3-O-(3',4'-O-diacetyl)-α-l-arabinopyranosylmaslinic acid (3), and 3-O-(3'-O-acetyl)-α-l-arabinopyranosyloleanolic acid (4), together with six known triterpenoids, 3-O-(4'-O-acetyl)-α-l-arabinopyranosyloleanolic acid (5), maslinic acid (6), 2-O-acetylmaslinic acid (7), 3-O-acetylmaslinic acid (8), betulinic acid (9), and 2α-hydroxy-3ß-O-acetylbetulinic acid (10), were isolated from the EtOAc extract of Garcinia hanburyi resin. Their structures were elucidated by analysis of the spectroscopic data and chemical methods.

Anti-Inflammatory Salicin Derivatives from the Barks of Salix tetrasperma.

The genus Salix L. is traditionally used in folk medicine to alleviate pain caused by various kinds of inflammation. In the present study, 10 undescribed salicin derivatives along with 5 known congeners were isolated from the barks of Salix tetrasperma, and their structures were elucidated by spectroscopic analyses, single-crystal X-ray diffraction, electronic circular dichroism (ECD) calculations, and chemical conversions. Compounds 4-6 significantly inhibited NO production in lipopolysaccharide (LPS)-induced RAW 264.7 macrophages, and the most active 4 obviously suppressed the production of IL-1ß and IL-6 and decreased iNOS and COX-2 expression in a dose-dependent manner. Further Western blotting analysis revealed that the anti-inflammatory mechanism of 4 is possibly mediated through the MAPK and NF-κB signaling pathways.

Monoterpenoid indole alkaloids from Alstonia scholaris and their Toxoplasma gondii inhibitory activity.

Nine previously unreported various types of monoterpenoid indole alkaloids, together with seven known analogues were isolated from the stem barks of Alstonia scholaris through a silica gel free methodology. The structures of 1-9 were elucidated by spectroscopic data analysis, electronic circular dichroism calculations, and single-crystal X-ray diffraction. Compound 1 is a modified echitamine-type alkaloid with a novel 6/5/5/7/6/6 hetero hexacyclic bridged ring system, and 8 and 9 exist as a zwitterion and trifluoroacetate salt, respectively. The anti-Toxoplasma activity of all isolates on infected Vero cells were evaluated, which revealed that compound 14 at 0.24 µM displayed potent activity. This study expanded the structural diversity of alkaloids of A. scholaris, and presented their potential application in anti-Toxoplasma drug development.

Paenibacillus typhae sp. nov., isolated from roots of Typha angustifolia L.

A Gram-stain-positive, facultatively anaerobic and rod-shaped bacterium, designated strain xj7(T), was isolated from roots of Typha angustifolia L. growing in Beijing Cuihu Wetland, China. The isolate was identified as a member of the genus Paenibacillus based on phenotypic characteristics and phylogenetic inference. The novel strain was spore-forming, motile, catalase-positive and oxidase-negative. Optimal growth of strain xj7(T) occurred at 28-30 °C and pH 7.0-7.5. Diphosphatidylglycerol was the most abundant polar lipid and occurred along with phosphatidylglycerol, phosphatidylethanolamine, one unknown phospholipid and three unknown aminophospholipids. The diamino acid found in the cell-wall peptidoglycan was meso-diaminopimelic acid. The predominant isoprenoid quinone was MK-7. The major fatty acid components were anteiso-C15 : 0 (56.1 %), iso-C16 : 0 (9.1 %), C16 : 0 (8.0 %), iso-C14 : 0 (6.3 %) and iso-C15 : 0 (5.1 %). The G+C content of genomic DNA was 47.9 mol%. Phylogenetic analysis based on the 16S rRNA gene sequence showed that strain xj7(T) fell within the evolutionary radiation encompassed by the genus Paenibacillus, its closest neighbours were Paenibacillus borealis KK19(T) (97.5 %) and Paenibacillus durus DSM 1735(T) (97.1 %). However, the DNA-DNA relatedness values between strain xj7(T) and P. borealis KK19(T) and between strain xj7(T) and P. durus DSM 1735(T), were both 35 %. Based on phenotypic, chemotaxonomic and phylogenetic properties, strain xj7(T) is considered to represent a novel species of the genus Paenibacillus, for which the name Paenibacillus typhae sp. nov. is proposed. The type strain is xj7(T) ( = CGMCC 1.11012(T) = DSM 25190(T)).

Comparison of the diversity of root-associated bacteria in Phragmites australis and Typha angustifolia L. in artificial wetlands.

Common reed (Phragmites australis) and narrow-leaved cattail (Typha angustifolia L.) are two plant species used widely in artificial wetlands constructed to treat wastewater. In this study, the community structure and diversity of root-associated bacteria of common reed and narrow-leaved cattail growing in the Beijing Cuihu Wetland, China, were investigated using 16S rDNA library and PCR-denaturing gradient gel electrophoresis methods. Root-associated bacterial diversity was higher in common reed than in narrow-leaved cattail. In both plant species, the dominant root-associated bacterial species were Alpha, Beta and Gamma Proteobacteria, including the genera Aeromonas, Hydrogenophaga, Ideonella, Uliginosibacterium and Vogesella. Acidobacteria, Actinobacteria, Nitrospirae and Spirochaetes were only found in the roots of common reed. Comparing the root-associated bacterial communities of reed and cattail in our system, many more species of bacteria related involved in the total nitrogen cycle were observed in reed versus cattail, while species involved in total phosphorus and organic matter removal were mainly found in cattail. Although we cannot determine their nutrient removal capacity separately, differences in the root-associated bacterial communities may be an important factor contributing to the differing water purification effects mediated by T. angustifolia and P. australis wetlands. Thus, further work describing the ecosystem functions of these bacterial species is needed, in order to fully understand how effective common reed- and narrow-leaved cattail-dominated wetlands are for phytoremediation.

Diterpenoids from Euphorbia lactea and their anti-HIV-1 activity.

Nine undescribed diterpenoids, euphlactenoids A-I (1-9), including four ingol-type diterpenoids (1-4) with a 5/3/11/3-tetracyclic framework and five ent-pimarane-type diterpenoids (5-9), together with thirteen known diterpenoids (10-22), were identified from the leaves and stems of Euphorbia lactea Haw. The structures and absolute configurations of compounds 1-9 were unequivocally elucidated on the basis of spectroscopic analysis, ECD calculations and single crystal X-ray diffraction. Compounds 3 and 16 showed anti-HIV-1 effects with IC50 values of 1.17 µM (SI = 16.54) and 13.10 µM (SI = 1.93), respectively.

Phorneroids A-M, diverse types of diterpenoids from Euphorbia neriifolia.

A chemical investigation on the aerial parts of Euphorbia neriifolia led to the identification of thirteen undescribed diterpenoids, phorneroids A-M, including ent-abietane (A-D), ent-kaurane (E-G), ent-atisane (H-K), and ent-isopimarane (L and M) types, together with three known compounds. Phorneroid A represents the first example of 8-spiro-fused 9,10-seco-ent-abietane diterpenoid lactone featuring a unique 6/5/6/5 spirocyclic framework. Biological assays showed that some of the compounds displayed moderate cytotoxicity against two human tumor cell lines, A549 and HL-60.