Terpenoids from Tripterygium doianum (Celastraceae)

The extract of Tripterygium doianum (Celastraceae) afforded three triterpenoids [3beta-acetoxy-11-ursen-13alpha,30-olide, 25-chloro-24-hydroxytirucall-7-en-3-one and tirucall-7-en-3,24-dione], two sesquiterpenoids [5alpha-acetoxy-1beta,8alpha-bis-cinnamoyl-4alpha-hydroxydihydroagarofuran and 5alpha-acetoxy-1beta-benzoyl-8alpha-cinnamoyl-4alpha-hydroxydihydroagarofuran] and nine known triterpenoids. Their structures were established based on spectroscopic studies.     

Medicinal chemistry and pharmacology of genus Tripterygium (Celastraceae)

Plants in the genus Tripterygium, such as Tripterygium wilfordii Hook.f., have a long history of use in traditional Chinese medicine. In recent years there has been considerable interest in the use of Tripterygium extracts and of the main bioactive constituent, the diterpene triepoxide triptolide (1), to treat a variety of autoimmune and inflammation-related conditions. The main mode of action of the Tripterygium extracts and triptolide (1) is the inhibition of expression of proinflammatory genes such as those for interleukin-2 (IL-2), inducible nitric oxide synthase (iNOS), tumor necrosis factor-alpha (TNF-alpha), cyclooxygenase-2 (COX-2) and interferon-gamma (IFN-gamma). The efficacy and safety of certain types of Tripterygium extracts were confirmed in human clinical trials in the US and abroad. Over 300 compounds have been identified in the genus Tripterygium, and many of these have been evaluated for biological activity. The overall activity of the extract is based on the interaction between its components. Therefore, the safety and efficacy of the extract cannot be fully mimicked by any individual constituent. This review discusses the biochemical composition and biological and pharmacological activities of Tripterygium extracts, and their main bioactive components.     

ent-Abietane diterpenoids from Isodon rubescens var. rubescens

ent-Abietane diterpenoids, hebeiabinins A-F (1-5), together with seven known diterpenoids were isolated from leaves of Isodon rubescens var. rubescens. The structures of 1-5 were established on the basis of spectroscopic analyses, including application of 2D NMR spectroscopic techniques. The diterpenoids isolated were evaluated for the cytotoxicity against A549, HT-29, and K562 tumor cells. Compound 5 was the most active with IC(50) value of 0.91 microM against A549 cells.     

ent-Verticillane-type diterpenoids from the Japanese liverwort Jackiella javanica

Three ent-verticillane diterpenoids and two ent-sesquiterpenoids were isolated from the Japanese liverwort Jackiella javanica Schiffn. together with five known ent-verticillane and three ent-kaurane diterpenoids, and three sesquiterpenoids. Five ent-verticillane epoxides were synthetically prepared from ent-verticillols action to clarify the absolute configuration of natural ent-9,10-epoxyverticillol. Their structures were established by extensive NMR spectroscopic and X-ray crystallographic analyses.     

ent-Isopimarane-type diterpenoids from the New Zealand liverwort Trichocolea mollissima

Two ent-isopimarane-type diterpenoids were isolated from the New Zealand liverwort Trichocolea mollissima (Hook. f. and Tayl.) Gott., together with a known 1alpha-hydroxy-ent-sandaracopimara-8(14),15-diene. Their absolute structures have been established by modified Mosher's method, X-ray crystallography and by analyses of their CD spectra.     

ent-Kaurene diterpenoids from Isodon oresbius

Three new ent-kaurene diterpenoids, oreskaurins A-C (1-3), together with ten known ent-kaurene diterpenoids, enmenin monoacetate (4), effusanin E (5), adenolin B (6), maoecrystal G (7), enmelol (8), trichokaurin (9), sodoponin (10), trichorabdal A (11), nodosin (12), enmein (13), and a flavonoid, vitexin (14), were isolated from Isodon oresbius. Their structures were determined by spectroscopic means. Compound 12 showed inhibitory activity toward K562 cells with IC(50)=1.43 microg/ml.     

New bioactive macrocyclic diterpenoids from Jatropha multifida

Two new macrocyclic diterpenoids, multifidanol (1) and multifidenol (2) along with several known compounds have been isolated from the stem of Jatropha multifida. The structures of the new compounds were established from the extensive studies of their 1D and 2D NMR spectra. The cytotoxic and antimicrobial activities of these two constituents were examined.     

ent-Beyerane diterpenoids from the heartwood of Excoecaria parvifolia

Chromatographic fractionations of the toluene extract of the heartwood of Excoecaria parvifolia collected in Australia resulted in the isolation of 12 beyerane diterpenes (1-12), and the triterpene, lupeol. Four of the isolated diterpenoids (5-7 and 12) have unusual structures: ent-3-oxa-beyer-15-en-2-one, (5); ent-15,16-epoxy-2-hydroxy-19-norbeyer-1,4-dien-3-one (6); methyl ent-2,4-seco-15,16-epoxy-4-oxo-3,19-dinorbeyer-15-en-2-oate (7); and ent-2,17-dihydroxy-19-norbeyer-1,4,15-trien-3-one (12). The structures were established by spectroscopic analyses, NMR data comparisons with similar diterpenes, and chemical correlations. All the diterpenes are assumed to have the same absolute configuration as the co-occurring (+)-stachenol (4). Diosphenol 2 and nor-lactone 5 exhibited significant potency in bioassays for cytotoxic activity against leukemia cells (L1210). Plausible biosynthetic pathways are proposed to explain the origin of the diterpene metabolites.     

Synthesis and biological evaluation of novel exo-methylene cyclopentanone tetracyclic diterpenoids as antitumor agents

The structure of exo-methylene cyclopentanone, which exists in nature tetracyclic diterpenoids products, has been proved to be an innate group for the treatment of cancer and inflammation. In this letter, four different scaffolds of tetracyclic diterpenoids including the structure exo-methylene cyclopentanone were synthesized from steviol and isosteviol and evaluated in vitro for their antitumor activity against three human cancer lines. Compounds 1a, 1b, 2b and 3b showed significant cytotoxicity, particularly, tetracyclic diterpenoids 2b, 3b were identified as the most potent and selective anticancer agents superior to adriamycin with IC₅₀ values of 0.9 μM and 1.5 μM, against Hep-G2 and MDA-MB-231 cell lines, respectively.     

Cytotoxic ent-kaurene diterpenoids from Isodon phyllostachys

ent-Kaurene diterpenoids, phyllostachysins D-H (1-5), together with nine known compounds, rabdoloxins A-B (6-7), rabdoinflexin B (8), amethystoidin A (9), rabdokunmin D (10), macrocalyxin E (11), 5,7-dihydroxy-4'-hydroxylflavone (12), oleanolic acid (13) and daucosterol (14), were isolated from aerial parts of Isodon phyllostachys. Structures were elucidated on the basis of spectroscopic methods, especially using 2D-NMR spectroscopic analyses. All ent-kaurenoids were tested for their cytotoxic effects against K562 cells. Compound 9 was the most potent with an IC50 value of 0.69 microg/ml.     

Further diterpenoids from Plectranthus ornatus and P. grandidentatus

A new halimane diterpenoid and the previously known labdane rhinocerotinoic acid were isolated from Plectranthus ornatus Codd. In addition, a new monoacetyl derivative of the abietane coleon U was found among the constituents of Plectranthus grandidentatus Gürke. These diterpenes could be significant from both chemotaxonomic and biogenetic points of view.     

Rearranged abietane diterpenoids from the root of Teucrium lanigerum

A new rearranged abietane diterpenoid, teuvincenone J, was isolated from the root of Teucrium lanigerum Lag. (Labiatae) together with four known compounds, teuvincenones A–D. The structure of the new diterpene [12,16-epoxy-11,14-dihydroxy-17(15 → 16)-abeo-3α,18-cyclo-8,11,13,15-abietatetraen-7-one] was established by 1D- and 2D-NMR spectroscopic means. These diterpenes could be significant from a chemotaxonomic point of view.     

Diterpenoids from Isodon enanderianus

Four ent-kauranoids, 6-epiangustifolin and enanderinanins F-H, as well as 11 known ent-kaurane diterpenoids, macrocalin B, xerophilusin A, trichorabdal A, trichorabdal B, effusin, angustifolin, longikaurin D, longikaurin F, enanderinanin B, xerophilusin G and shikokianin were isolated from the aerial parts of Isodon enanderianus. The new diterpenoids were identified as 6-epiangustifolin (11alpha-hydroxy-6alpha-methoxy-6,19-epoxy-6,7-seco-ent-kaur-16-en-15-one-7,20-olide), enanderinanin F (19-acetoxy-6,20:6,11beta-diepoxy-6,7-seco-ent-kaur-16-en-15-one-1beta,7-olide), enanderinanin G (1beta,6beta,7beta-trihydroxy-19-acetoxy-16beta-methoxymethyl-7alpha,20-epoxy-ent-kaur-15-one) and enanderinanin H (6beta,7beta,14beta-trihydroxy-1alpha,11beta-acetonide-7alpha,20-epoxy-ent-kaur-16-en-15-one), respectively, on the basis of spectral data, especially by 2D NMR techniques. 6-Epiangustifolin showed significant cytotoxic activity against K562 cell.     

Three labdane diterpenoids from Aframomum sceptrum (Zingiberaceae)

Three labdane diterpenoids, 8beta,17-epoxy-3beta,7beta-dihydroxy-12(E)-labden-16,15-olide (1), methyl 8beta,17-epoxy-3beta,7beta,15-trihydroxy-12(E)-labden-16-oate (2) and 3beta,7beta,8beta,12zeta,17-pentahydroxylabdan-16,15-olide (3) have been isolated from the seeds of Afromomum sceptrum K. Schum (Zingiberaceae) and their structures assigned on the basis of their spectroscopic properties. Nerolidol, and the known flavonoids 3-acetoxy-4',5,7-trihydroxyflavanone, and 3,4',5,7-tetrahydroxyflavanone were also obtained.     

Phylogeny of the Celastreae (Celastraceae) and the relationships of Catha edulis (qat) inferred from morphological characters and nuclear and plastid genes

The phylogeny of Celastraceae tribe Celastreae, which includes about 350 species of trees and shrubs in 15 genera, was inferred in a simultaneous analysis of morphological characters together with nuclear (ITS and 26S rDNA) and plastid (matK, trnL-F) genes. A strong correlation was found between the geography of the species sampled and their inferred relationships. Species of Maytenus and Gymnosporia from different regions were resolved as polyphyletic groups. Maytenus was resolved in three lineages (New World, African, and Austral-Pacific), while Gymnosporia was resolved in two lineages (New World and Old World). Putterlickia was resolved as nested within the Old World Gymnosporia. Catha edulis (qat, khat) was resolved as sister to the clade of Allocassine, Cassine, Lauridia, and Maurocenia. Gymnosporia cassinoides, which is reportedly chewed as a stimulant in the Canary Islands, was resolved as a derived member of Gymnosporia and is more closely related to Lydenburgia and Putterlickia than it is to Catha. Therefore, all eight of these genera are candidates for containing cathinone- and/or cathine-related alkaloids.     

Eudesmane sesquiterpenoid lactones and abietane diterpenoids from Ajuga forrestii Diels

Four eudesmane sesquiterpenoid lactones (1–4) and seven abietane diterpenoids (5–11) were isolated from the whole plants of Ajuga forrestii. Among them, 3α-acetoxy-1α,8β-dihydroxyeudesm-7(11)-en-8,12-olide (1), 3α-acetoxy-1α-hydroxyl-eudesm-8,7(11)-dien-8,12-olide (2), 1α-acetoxy-8α-oxyethyl-2-oxo-eudesman-3,7(11)-dien-8,12-olide (3) and 2α,3β,11,12-tetrahydroxy-7β,20-epoxy-8,11,13-abietatriene (11) are novel compounds. The structures of compounds 1–11 were determined by spectroscopic analysis. Compound 2 exhibited weak cytotoxicity on HepG2 and MCF-7 cell lines.     

Ent-3,4-seco-labdane and ent-labdane diterpenoids from Croton stipuliformis (Euphorbiaceae)

From a methanolic extract of the leaves of Croton stipuliformis, three ent-3,4-seco-labdanes (1-3) and an ent-labdane (4) together with the known compounds 6-hydroxynidorellol (5), maravuic acid, and sitosterol were isolated and identified from their spectroscopic data. The absolute stereochemistry of compound 4 was determined by application of Mosher's method in the NMR tube.