Lathyranoic Acid A: First Secolathyrane Diterpenoid in Nature from Euphorbia lathyris

[structures: see text] Lathyranoic acid A (1), the first secolathyrane diterpenoid with an unprecedented skeleton, and a new diterpenoid Euphorbia factor L11 (2) were isolated from the seeds of Euphorbia lathyris. Their structures were elucidated by spectroscopic analysis and chemical methods. A biogenetic route involving an enzymatic Baeyer-Villiger oxidation as the key step was postulated for the transformation of 2 to 1 and mimicked by an unusual chemical Baeyer-Villiger oxidation.

Swietenia mahagony extract shows agonistic activity to PPAR(gamma) and gives ameliorative effects on diabetic db/db mice

AIM

To search the peroxisome proliferator-activated receptor g (PPAR(gamma)) agonists from Swietenia mahagony extract (SmE) and observe the possible ameliorative effects of SmE on diabetic db/db mice.

METHODS

The PPAR(gamma) agonistic activity of SmE was screened by yeast-two hybrid system. The blood glucose levels of diabetic db/db mice were measured using a blood glucose level monitor and the data were statistically analyzed by NDST8.8W software.

RESULTS

By using the clinical drug rosiglitazone as a positive control, it was found that the PPARg agonistic activity of SmE at a concentration of 50 microg/L was approximately half that of 35.7 microg/L (0.1 micromol/L) of rosiglitazone. At the dose of 1000 mg/kg, SmE remarkably decreased the blood glucose concentration of db/db mice from (15.26+/-2.98) to (7.58+/-2.20) mmol/L, and reduced the blood glucose levels by 55.49% compared with the control group (P<0.01).

CONCLUSION

SmE shows agonistic activity to PPARg and can ameliorate the blood glucose levels of diabetic db/db mice. SmE may be thus used as a potential agent for diabetes therapy.

Lignans and their degraded derivatives from Sarcostemma acidum

Four lignans, sacidumlignans A-D (1-4), and two degraded lignan derivatives, sacidumols A (5) and B (6), along with four known compounds, (+)-pinoresinol, 9alpha-hydroxypinoresinol, perforatic acid, and peucenine-7-O-methyl ether, were isolated from the ethanolic extract of the whole plant of Sarcostemma acidum. The structures and relative configuration of these new compounds were elucidated on the basis of spectroscopic and chemical data, especially 2D NMR techniques. Sacidumlignan D (4) was assigned as a rearranged tetrahydrofuran lignan with an unprecedented skeleton. Sacidumlignan A (1) showed moderate antimicrobial activities against two Gram-positive bacteria in vitro.

Novel diterpenoids with potent inhibitory activity against endothelium cell HMEC and cytotoxic activities from a well-known TCM plant Daphne genkwa

Twelve highly oxygenated novel daphnane-type diterpenoids genkwanines A-L (1-12), together with four known diterpenes (13-16), were isolated from the bud of Daphne genkwa, a well-known traditional Chinese medicine (TCM). The new structures were elucidated on the basis of spectral methods, especially 2D NMR spectra (HMQC, HMBC, NOESY). Inhibitory activity against endothelium cell HMEC proliferation and cytotoxic activities against two tumor cell lines were assessed for all the compounds 1-16, and found to be significant and structure related. A number of compounds showed very potent cytotoxic activities against two tumor cell lines at the IC50 levels of 0.15-8.40 microM, and most interestingly, five of the compounds 4, 8, 10, 13, and 14 exhibited strong activity to inhibit the endothelium cell HMEC at the IC50 levels of 2.90-15.0 microM.

Pseudolarix acid B inhibits angiogenesis by antagonizing the vascular endothelial growth factor-mediated anti-apoptotic effect

Angiogenesis is controlled by a number of growth factors, including vascular endothelial growth factor (VEGF). In this study, pseudolarix acid B, isolated from the traditional Chinese medicinal plant Pseudolarix kaempferi and originally identified as an early pregnancy-terminating agent, was evaluated for its potential as an angiogenesis inhibitor, using in vitro and in vivo models. After exposure to pseudolarix acid B 0.625-5 microM for 72 h, the proliferation of human umbilical vein endothelial cells was significantly inhibited. Pseudolarix acid B 0.313-2.5 microM for 24 h potently blocked the VEGF-induced tube formation of human umbilical vein endothelial cells in a dose-dependent manner. Matrigel plug assays disclosed that pseudolarix acid B reduced angiogenesis induced by VEGF in vivo. In addition, pseudolarix acid B antagonized VEGF-mediated anti-apoptotic effects on serum-deprived human umbilical vein endothelial cells and increased apoptosis of endothelial cells induced by VEGF in Matrigel plug assays. Moreover, pseudolarix acid B significantly inhibited VEGF-induced tyrosine phosphorylation of kinase insert domain-containing receptor/fetal liver kinase-1 (KDR/flk-1), in correlation with a marked decrease in the phosphorylation of Akt and extracellular signal-regulated kinases (ERK). These findings collectively suggest that pseudolarix acid B possesses anti-angiogenic activity. One of the main anti-angiogenesis mechanisms of pseudolarix acid B may involve antagonism of the VEGF-mediated anti-apoptosis effect via inhibition of KDR/flk-1, ERK1/2, and Akt phosphorylation in endothelial cells.

Novel Antibacterial Diterpenoids fromLarix chinensis Beissn

Two novel labdane-type diterpenoids, butanedioic acid mono[(13S)-13-hydroxylabda-8(17),14-dien-19-yl] ester (1) and butanedioic acid bis[(13S)-13-hydroxylabda-8(17),14-dien-19-yl] ester (2), along with the eleven known diterpenoids 3-13 and three other known compounds, were isolated from the bark of Larix chinensis. Their structures were elucidated both spectroscopically and chemically. The major diterpenoids 1-9, 11, and 13, as well as the very abundant phenolic compound 16, were subjected to antibacterial and cytotoxic bioassays. Compounds 7 and 9 showed remarkable in vitro inhibition of Staphylococcus aureus and S. epidermidis (MIC = 37-73 microM).

Chemical constituents fromPseudolarix Kaempferi

A novel degraded triterpenoid isopseudolaritone A (1) and one new oligosaccharide, 1-O-isopropyl-6-O-[2-O-methyl-alpha-L-rhamnopyranosyl(1 --> 6)]-beta-D-glucopyranose (2), two new artefacts, 9-O-formacyl cedrusin (5) and 9,9'-O-diformacyl cedrusin (6), as well as 12 known phenolic Compounds (3-4, 7 16), were isolated from the root bark of Pseudolarix kaempferi. Their structures were elucidated mainly by spectroscopic methods.

Oldhamiphylline A: a Novel Hexacyclic Alkaloid fromDaphniphyllum oldhami

A novel Daphniphyllum alkaloid, oldhamiphylline A (1), together with five known alkaloids, deoxycalyciphylline B, deoxyisocalyciphylline B, calyciphylline, secodaphniphylline, and calycicine A, was isolated from the leaves of Daphniphyllum oldhami. The structure of 1 was established by spectroscopic methods, especially 2D NMR techniques (1H,1H-COSY, HMQC, HMBC, and NOESY).

Novel diterpenoids and diterpenoid glycosides from Siegesbeckia orientalis

Eight new ent-pimarane diterpenoids and diterpenoid glycosides, namely, ent-12alpha,16-epoxy-2beta,15alpha,19-trihydroxypimar-8-ene (1), ent-12alpha,16-epoxy-2beta,15alpha,19-trihydroxypimar-8(14)-ene (2), ent-2alpha,15,16,19-tetrahydroxypimar-8(14)-ene, ent-15-oxo-2beta,16,19-trihydroxypimar-8(14)-ene, ent-2-oxo-15,16-dihydroxypimar-8(14)-en-16-O-beta-glucopyranoside, ent-2-oxo-15,16,19-trihydroxypimar-8(14)-ene, ent-2-oxo-3beta,15,16-trihydroxypimar-8(14)-en-3-O-beta-glucopyranoside, and ent-2beta,15,16,19-tetrahydroxypimar-8(14)-en-19-O-beta-glucopyranoside, together with seven known diterpenes were isolated from Siegesbeckia orientalis. Compounds 1 and 2 are novel ent-pimarane diterpenoids with an unprecedented 12alpha,16-epoxy group. Their structures were established by spectral methods, especially 1D and 2D NMR spectral methods.

Cytotoxic sesquiterpene lactones from Eupatorium lindleyanum

Ten new guaiane type sesquiterpene lactones, namely, eupalinilides A-J (1-10), as well as nine known compounds, eupachinilide C (11), eupachifolin D (12), eupachinilide E (13), 2alpha-hydroxyeupatolide (14), 3-deacetyleupalinin A (15), heliangine (16), 8beta-tigloyloxy-2,3-seco-6betaH,7alphaH-helianga-4Z,11(13)-diene-3,10beta;6, 12-diolid-2-oic acid (17), 8beta-(4'-hydroxytigloyloxy)-3beta,14-dihydroxy-6betaH,7alphaH-germacra-1(10)Z,4Z,11(13)-trien-6,12-olide (18), and 8beta-tigloyloxy-3beta,14-dihydroxy-6betaH,7alphaH-germacra-1(10)Z,4E,11(13)-trien-6,12-olide (19), were isolated from the whole plant of Eupatorium lindleyanum. Eupalinilides B (2), C (3), E (5), F (6), and I (9) have been tested for cytotoxicity against P-388 and A-549 tumor cell lines. The results showed that eupalinilides B (2) and E (5) demonstrated potent cytotoxicity. The structures of these compounds were determined by spectroscopic methods including 1D and 2D NMR spectra.

Antibacterial prenylflavone derivatives from Psoralea corylifolia, and their structure–activity relationship study

Three new prenylflavonoids, namely corylifols A-C (1-3), together with 13 known ones, were isolated from the seeds of Psoralea corylifolia. Their structures were elucidated by spectral methods including 1D and 2D NMR techniques. All the isolates were tested on antibacterial assays, and nine of them showed significant antibacterial activities against two pathogenic bacteria Staphylococcus aureus and S. epidermidis. The antibacterial structure-activity relationship of these prenylflavonoids (1-16) was also briefly discussed.

Antifungal diterpenoids of Pseudolarix kaempferi, and their structure-activity relationship study

The in vitro antifungal activities of 19 structurally diversified analogues of pseudolaric acids tested against the major pathogenic fungus Candida albicans has led to the establishment of a very clear structure-activity relationship of pseudolaric acids derivatives. Pseudolaric acid A was first found to be a potent antifungal component comparable with pseudolaric acid B. Among the tested 19 diterpenoids, pseudolaric acids A2 (1), B2 (3), B3 (4) and methyl pseudolarate A2 (2) are new isolates of the root bark of Pseudolarix kaempferi, and their structures were elucidated mainly by 2D-NMR techniques and chemical methods. Compounds 12-19 were first semi-synthesized by efficient routines from pseudolaric acid B.

First Diamino Daphniphyllum Alkaloid, Daphnipaxinin, with an Unprecedented Heterohexacyclic Skeleton from Daphniphyllum paxianum

[structure: see text] The first diamino Daphniphyllum alkaloid, daphnipaxinin (1), with an unprecedented hexacyclic fused skeleton, along with a known alkaloid, daphnicyclidin A (2), was isolated from the stem of Daphniphyllum paxianum Rosenth. The structure and absolute stereochemistry of 1 were established by spectral methods, especially two-dimensional NMR techniques and CD analysis.

Cytotoxic sesquiterpenoids from Eupatorium chinense

Ten new sesquiterpenoids, namely, eupachinilides A-J (1-10), together with seven known sesquiterpenoids, eupachifolin D (11), budlein B (12), 8 beta-(4'-hydroxytiglyloxy)-2 beta-hydroxy-1 alpha H,5 alpha H,6 beta H,7 alpha H-guai-3,10(14),11(13)-trien-6,12-olide (13), 1,10-hydrobahia (14), 2 alpha-hydroxyeupatolide (15), eupaserrin (16), and mollisorin B (17), were isolated from the whole plant of Eupatorium chinense. Their structures were elucidated mainly by spectral methods, especially 2D NMR techniques. Eupachinilides A (1), E (5), F (6), and I (9) exhibited moderate cytotoxic activities against several tumor cell lines. The structures assigned previously for eupachifolins B (11a), C (13a), and D (11) were revised by spectral analysis and 2D NMR techniques.

Two novel alkaloids with a unique fused hexacyclic skeleton from Daphniphyllum subverticillatum

Two novel major alkaloids, deoxycalyciphylline B (1) and deoxyisocalyciphylline B (2) with a unique fused hexacyclic skeleton, together with a quite recently reported alkaloid calyciphylline B (3), were isolated from the stem of Daphniphyllum subverticillatum. Their structures were established by spectral methods and chemical evidence, especially 2D NMR techniques. The structure of 1 was further confirmed by a single-crystal X-ray diffraction determination.

Paxdaphnidines A and B, Novel Penta- and Tetracyclic Alkaloids from Daphniphyllum paxianum

Two novel alkaloids, paxdaphnidine A (1) with a unique pentacyclic skeleton and paxdaphnidine B (2) with an uncommon tetracyclic skeleton, were isolated from the stems and leaves of Daphniphyllum paxianum. Their structures were established by spectral methods, especially two-dimensional NMR techniques ((1)H-(1)H COSY, HSQC, HMBC, and NOESY).

New glyceroglycolipid and ceramide from Premna microphylla

Two new compounds (1,2) were isolated from the ethanolic extract of the leaves of Premna microphylla, together with five known compounds. The structures of compounds 1 and 2 were elucidated as (2S,3S,4R,11E)-2-[(2R)-2-hydroxytetracosanoylaminol-11-octadecene-1,3,4-triol (1) and 1-O-(9Z,12Z, 15Z-octadecatrienoyl)-3-O-[beta-D-galactopyranosyl-(1 --> 6)- O-beta-D-galactopyranosyl-(1 --> 6)-alpha-D-galactopyranosyl] glycerol (2) by means of spectroscopic and chemical methods.

New glycosphingolipids from the fungus Catathelasma ventricosa

Three new glycosphingolipids with a cis-Delta(17)-fatty acyl moiety, namely, catacerebrosides A-C (1-3), along with two known glycosphingolipids, cerebrosides B and D, six known ergostane-type sterols, and tyrosamine were isolated from the fungus Catathelasma ventricosa. The structures of 1-3 were elucidated on the basis of spectroscopic analysis and chemical methods.