Two new lanostane triterpenoids from Poria cocos

Two new lanostane triterpenoids, 29-hydroxypolyporenic acid C (4) and 25-hydroxypachymic acid (5), together with three known compounds, ergosta-7,22-dien-3β-ol (1), polyporenic acid C (2) and pachymic acid (3), were isolated from the 95% ethanolic extract of the sclerotium of Poria cocos (Schw.) Wolf. Their structures were determined by extensive spectroscopic analyses, including IR, UV, ESITOF-MS, HRESI-MS, 1D and 2D NMR data (¹H NMR, ¹³C NMR, ¹H-¹H COSY, NOESY, HSQC and HMBC).     

Stilbene derivatives from Gnetum cleistostachyum

Three new stilbene derivatives, named gnetucleistol A (1), B (2) and C (3), together with four known compounds, gnetifolin A (4), p-hydroxycinnamic acid (5), piceatannol (6) and resveratrol (7), were isolated from Gnetum cleistostachyum C.Y. Cheng (Gnetaceae). Their structures were elucidated on the basis of spectroscopic evidence (EI-MS, UV, IR, NOE, ¹H, ¹³C and 2D NMR).     

Cytotoxic sesquiterpene lactones from Eupatorium lindleyanum

Three new germacrane sesquiterpenes, eupalinolides C-E (1-3), along with three known germacrane sesquiterpenes, eupalinolide A (4), eupalinolide B (5), and 3β-acetoxy-8β-(4'-hydroxytigloyloxy)-14-hydroxycostunolide (6), were isolated from Eupatorium lindleyanum. They were tested for cytotoxicity against A-549, BGC-823, SMMC-7721, and HL-60 tumour cell lines. The results showed that these compounds demonstrated potent cytotoxicity. The structures of the compounds were elucidated by means of ¹H and ¹³C NMR spectroscopic analysis, including 2D NMR experiments.     

New dibenz[b, f]oxepins from Cercis chinensis Bunge

Three new dibenz[b,f]oxepins: 6-methoxy-7-methyl-8-hydroxydibenz[b, f]oxepin (1), 1,8-dimethoxy-6-hydroxy-7-methyldibenz[b, f]oxepin (2), and 1-hydroxy-6,8-dimethoxy-7-methyldibenz[b,f]oxepin (3), along with two known dibenz[b,f]oxepins pacharin (4) and bauhiniastatin 4 (5), were isolated from Cercis chinensis Bunge (Leguminosae). Their structures were elucidated on the basis of spectroscopic evidence (EI-MS, UV, IR, ¹H, ¹³C and 2D NMR). Compounds 1-5 were isolated from the Cercis genus for the first time.     

Antibacterial constituents from Stemona sessilifolia

Bioassay-guided fractionation led to the isolation of eight compounds from Stemona sessilifolia. Of the eight isolates, three new bibenzyls, stilbostemins M-O (1-3), and a new tocopherol, 6-methoxy-3,4-dehydro-δ-tocopherol (4) were revealed together with four known compounds 3,5-dihydroxy-2'-methoxy bibenzyl (5), 3,5-dihydroxy bibenzyl (6), β-tocopherol (7), and γ-tocopherol (8). Compounds 5, 6, and 8 exhibited strong antibacterial activities against Staphylococcus aureus and S. epidermidis.     

Two new iridoid glucosides from Picrorhiza scrophulariiflora

Two new iridoid glucosides with 3,4-dihydrocatalpol skeleton, piscrosides A (1) and B (2) together with nine known iridoid glucosides and three known cucurbitacin glucosides, were isolated from the stems of Picrorhiza scrophulariiflora. Their structures were established by MS, ¹H NMR, ¹³C NMR and 2D NMR methods (including HSQC, HMBC and NOESY experiments).     

Chemical constituents of Centella asiatica

Studies on the chemical constituents of the aerial part of Centella asiatica have led to the isolation of three new compounds, named centellin (1), asiaticin (2), and centellicin (3). Their structures have been elucidated through spectral studies including 2D NMR experiments (HMQC, HMBC, ¹H-¹H COSY, NOESY and J resolved).     

Stilbenoids from Stemona japonica

Three new dihydrostilbenes, stilbostemins J-L (1-3), and a new dihydrophenanthrene, stemanthrene F (4), were isolated from the roots of Stemona japonica together with two known bibenzyls, 3,5-dihydroxy-4-methylbibenzyl (5) and 3,5-dihydroxy-2'-methoxy-4-methylbibenzyl (6). Their structures were elucidated by spectroscopic analyses. Compounds 3-6 exhibited strong antibacterial activities against Staphylococcus aureus and Staphylococcus epidermidis.     

Neolignan and lignan glycosides from branch bark of Davidia involucrata

Two new neolignan glycosides, davidioside A (1) and davidioside B (2), have been isolated along with six known compounds from the branch bark of Davidia involucrata. Identification of their structures was achieved by 1D and 2D NMR experiments, including ¹H-¹H COSY, NOESY, HMQC, and HMBC methods as well as FAB mass spectral data.     

Harzianums A and B produced by a fungal strain, Hypocrea sp. F000527, and their cytotoxicity against tumor cell lines

A new compound, harzianum B (1), was isolated from the culture broth of a fungal strain, Hypocrea sp. F000527, together with a known trichothecene, harzianum A (2). Its structure was determined by spectroscopic analyses including HRFAB-MS and various ¹H NMR and ¹³C NMR spectral data. Harzianum B (1) was characterised as (E,Z,E)-2', 4', 6'-octatriendioic acid esterified on the 4β-hydroxyl group of trichodermol. Harzianums A (2) and B (1) showed cytotoxicity against several human cancer cell lines.     

Triterpene saponins from Lysimachia christinae

Seven triterpene saponins were isolated from Lysimachia christinae and identified as lysichriside A (1), lysichriside B (2), primulanin (3), lysikokianoside 1 (4), anagallisin C (5), ardisiacrispin A (6), and ardisicrenoside B (7). Compounds 1 and 2 are new triterpene saponins, compounds 3, 5, and 7 were isolated from this genus, and compounds 4 and 6 were isolated from this species for the first time. Their structures were elucidated by means of 1D and 2D NMR experiments.     

Two new caffeyol glycosides from Forsythia suspensa

Two new caffeoyl glycosides of phenethyl alcohol, suspensaside A (1) and suspensaside B (2), were isolated from the fruits of Forsythia suspensa. Also obtained in this investigation were two known compounds forsythiaside (3) and suspensaside (4). The structures of compounds 1 and 2 were established by 1D and 2D NMR techniques and chemical methods.     

Two new 18-carbon norditerpenoid alkaloids from Aconitum sinomontanum

Two new 18-carbon norditerpenoid alkaloids, sinaconitines A (1) and B (2), together with two known alkaloids, ranaconitine (3) and lappaconitine (4), were isolated from the roots of Aconitum sinomontanum. Their structures were elucidated on the basis of spectral evidences and X-ray crystallographic analysis for 1. Furthermore, the reversed ¹³C NMR assignments for C-10 and C-13 of 3, 4, puberanine, puberanidine and demethyllappaconitine were revised. Compounds 1-4 were evaluated for cyclooxygenase-2 (COX-2) enzyme inhibitory activity. However, they did not show any inhibition at 10 μM.     

New guaianolides from Artemisia selengensis

A new guaianolide artselenin (1) and a new dimeric guaianolide artselenoid (2), along with 10 known compounds, were isolated from the aerial parts of Artemisia selengensis. Their structures were elucidated by spectroscopic methods. Two-dimensional NMR techniques were used to make complete assignments for the ¹H- and ¹³C-NMR chemical shifts of the two new guaianolides.     

New tetracyclic diterpenoid and new ceramides from the soft coral Sinularia conferta

The new tetracyclic diterpenoid confertdiate (1) and two new ceramides, (2) and (3), have been isolated from the soft coral Sinularia conferta, collected from Sanya Bay, Hainan Island, China. Their structures have been elucidated by spectroscopic analysis, and comparison of the ¹³C NMR data with those of the known diterpenoid isomandapamate confirmed the structure of 1.     

Three new triterpenoid saponins from the rhizomes of Impatiens pritzellii var. hupehensis

Three new triterpenoid saponins, impatiprins A-C (1-3), together with a known triterpenoid (4) and two known triterpenoid saponins (5, 6), were isolated from the rhizomes of Impatiens pritzellii Hook. f. var. hupehensis Hook. f. The structures of 1-3 were determined by 1D and 2D NMR, FAB-MS techniques and chemical methods. Compounds 1 and 2 showed weak cytotoxicities against S-180, HeLa and HepG2 cell lines.     

O-methyl nakafuran-8 lactone, a new sesquiterpenoid from a hainan marine sponge Dysidea sp

A new sesquiterpenoid, O-methyl nakafuran-8 lactone (1) has been isolated from a Hainan sponge Dysidea sp. and the structure of the new compound proposed by spectral data, was confirmed by X-ray diffraction analysis. The complete ¹H- and ¹³C-NMR assignments were made on the basis of detailed 2D NMR spectral analysis.

Compound 1 showed strong inhibitory bioactivity against PTP1B with IC₅₀ value of 1.58 μM.     

Terpenoids and sterols from Lagerstroemia speciosa

The leaves of Lagerstroemia speciosa afforded a new natural product, 31-norlargerenol acetate (4), along with known compounds 24-methylenecycloartanol acetate (1), its 31-nor analog (2), largerenol acetate (3), tinotufolins C (5) and D (6), lutein, phytol, sitosterol and sitosterol acetate. The structure of 4 was elucidated by 1D and 2D NMR and mass spectroscopy.     

Coumarins from Coriaria nepalensis

Two new coumarins (1) and (2), along with seven known coumarins 3-9, were isolated from the leaves and stems of Coriaria nepalensis Wall. The two new compounds were established as 7-hydroxy-6-methoxy-3,8-bis(3-methyl-2-butenyl) coumarin (1) and 7-hydroxy-6-methoxy-3-(3-methyl-2-butenyl) coumarin (2), on the basis of 1D and 2D NMR techniques. The known compounds 3, 6-9 were isolated from this plant for the first time.     

Antioxidant phenolic glucosides from Gentiana piasezkii

An extract of Gentiana piasezkii afforded a new arbutin derivative 6'-O-vanilloylarbutin (1) and a new flavone-C-glucoside 7-O-feruloylorientin (2), together with four known flavonoids lutonarin (3), saponarin (4), isoorient (5) and luteolin (6). Their structures were established based on spectroscopic methods including 2D NMR (COSY and gHMBC) techniques. Compounds 1, 2, 5 and 6 were evaluated for the antioxidant activity in the 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay system.