Further Diterpenes from the Seeds of Caesalpinia minax Hance

Three new cassane‐type diterpenes, neocaesalpin AF ( 1 ), neocaesalpin AG ( 2 ), and neocaesalpin AH ( 3 ), were isolated from the seeds of Caesalpinia minax Hance . Their structures were elucidated on the basis of extensive spectroscopic analyses. The partially hydrogenated lactone unit in a tetracyclic cassane diterpene in 2 is rarely encountered in the cassane diterpenes isolated from the genus Caesalpinia. All compounds were evaluated for their in vitro cytotoxic activities against HCT‐8 and MCF‐7 human cancer cell lines.     

Three New Cassane‐Type Diterpenes from Caesalpinia minax

Three new cassane‐type diterpenes, 14‐dehydroxy‐12,16‐dihydrocaesaldekarin L ( 1 ), 1‐deacetyl‐12‐ethoxyneocaesalpin N ( 2 ), and 1‐deacetylneocaesalpin N ( 3 ), together with two known cassane‐type diterpenes, neocaesalpin A and neocaesalpin L, were isolated from the EtOH extract of the twigs and leaves of Caesalpinia minax. Their structures were elucidated by spectroscopic methods, as well as by comparison of their spectral data with those of related compounds.     

Verticillane‐Type Diterpenoids and an Eudesmanolide‐Type Sesquiterpene from the Formosan Soft Coral Cespitularia hypotentaculata

Four new diterpenes, cespihypotins W–Z ( 1 – 4 ), having the verticillane skeleton and characterized by an α,β‐unsaturated γ‐hydroxycyclopentanone moiety, and a new eudesmanolide‐type sesquiterpene, cespilactam A ( 5 ), containing an α,β‐unsaturated γ‐lactam residue, were isolated from the AcOEt‐soluble fraction of the Taiwanese soft coral Cespitularia hypotentaculata. The structure and relative configuration of these metabolites was elucidated through extensive interpretation of MS, COSY, HSQC, HMBC, and NOESY experiments and by comparison of their NMR data with those of related compounds.     

New Antibacterial Diterpenes from Pseudopterogorgia elisabethae

From the MeOH extract of Pseudopterogorgia elisabethae, collected from the Bahamas, four new diterpenes, elisabethin E ( 1 ), elisabethin F ( 2 ), pseudopterosin P ( 3 ), and pseudopterosin Q ( 4 ), were isolated and their structures established with the aid of extensive spectroscopic studies. Compounds 3 and 4 showed antibacterial activity selectively against the Gram‐positive bacteria Streptococcus pyogenes, Staphylococcus aureus, and Enterococcus faecalis.     

New Eunicellin Diterpenes and 9,10‐Secosteroids from the Gorgonian Muricella sibogae

Bioactivity‐guided isolation of the rare gorgonian Muricella sibogae (Nutting ) yielded the two new eunicellin diterpenes sibogin A and B ( 1 and 2 ), the three new 9,10‐secosteroids sibogol A–C ( 6 – 8 ), together with the three known eunicellin diterpenes 3 – 5 and the five known 9,10‐secosteroids 9 – 13 . Their structures were established by extensive spectral analysis (1D‐ and 2D‐NMR, IR, and MS). The cytotoxicity of the isolates 1 – 13 was evaluated in vitro against the selected tumor cell lines P388 and BEL‐7402. All the compounds showed only weak activity against P388 cell lines, with an inhibition rate ranging from 10 to 60% at a concentration of 50 μg/ml, whereas the were inactive against BEL‐7402 cell lines.     

Quinone derivatives by chemical transformations of 16-hydroxycarnosol from Salvia species

The known diterpenes 12,16-epoxycarnosol (2), isotanshinone II (6), and (+)-neocryptotanshinone (8) were obtained by partial synthesis from 16-hydroxycarnosol (1), a C-16 hydroxylated abietatriene diterpene isolated in relative abundance from the aerial part of Salvia mellifera GREENE. The physical and spectroscopic data of these semisynthetic diterpenes were identical to those given for the natural ones in the literature. These abietane diterpenes have very interesting biological activities and the semisynthetic approach described here represents an alternative to obtain them from other major diterpenes isolated from Salvia species. Additionally, seven new semisynthetic diterpene analogues, 11,14-dioxo-12,16-epoxy-8,12-abietadien-20,7beta-olide (3), 11,14-dioxo-12,16-epoxy-8,12,15(16)-abietatrien-20,7beta-olide (4), 15,16-didehydro-12,16-epoxycarnosol (5), 1-oxoisotanshinone II (7), 16-hydroxycolumbaridione (9), 12,16-diacetoxycolumbaridione (10), and 14-methoxy-12,16-epoxycarnosol (13), were obtained from 1. The structures of the new compounds were established based on their spectroscopic data.     

Pintoxolanes A–C,Highly Functionalized 3,14‐Oxa‐bridged Cembranoids from the Caribbean Gorgonian Coral Eunicea pinta

Three new cembrane‐based diterpenes possessing the rare 3,14‐oxa‐bridged moiety were isolated from the hexane extract of a southwestern Caribbean gorgonian octocoral, Eunicea pinta, together with seven known cembranoid diterpenes. The structures of pintoxolanes A–C ( 1 – 3 , resp.), including their relative configurations, were deduced from spectroscopic data and chemical‐correlation experiments. Experimental evidence hinting to a plausible biogenesis of the 3,14‐oxalane moiety is provided. Preliminary cytotoxicity data for compounds 1 – 3 toward human cancer cell lines are also provided.     

Constituents of the Vietnamese medicinal plant Orthosiphon stamineus

From the MeOH extract of the aerial part of Vietnamese Orthosiphon stamineus, five new isopimarane-type diterpenes [orthosiphols F-J (1-5)] and two new diterpenes [staminols A (6) and B (7)] with a novel carbon-framework, to which we proposed the name "staminane", and three new highly-oxygenated staminane-type diterpenes [staminolactones A (8) and B (9) and norstaminol A (10)1 were isolated. Moreover, staminolactone A (8) is 8,14-secostaminane-type and staminolactone B (9) is 13,14-secostaminane-type, while norstaminol A (10) is 14-norstaminen-type. Together with these new diterpenes, sixteen known compounds were also isolated and identified to be: 7,3',4'-tri-O-methylluteolin (11), eupatorin (12), sinensetin (13), 5-hydroxy-6,7,3',4'-tetramethoxyflavone (14), salvigenin (15), ladanein (16), tetramethylscutellarein (17), 6-hydroxy-5,7,4'-trimethoxyflavone (18), vomifoliol (19), aurantiamide acetate (20), rosmarinic acid (21), caffeic acid (22), oleanolic acid (23), ursolic acid (24), betulinic acid (25), and beta-sitosterol (26). All the isolated compounds were tested for their cytotoxicity towards highly liver metastatic murine colon 26-L5 carcinoma cells, and the new diterpenes, except for 4, and flavonoids (11, 12, 16, 18) showed cytotoxicity with an ED50 value between 10 and 90 microg/ml.     

ent‐Kaurane Diterpenes and Further Constituents from Wedelia trilobata

Two new ent‐kaurane diterpenes, wedelidins A ( 8 ) and B ( 9 ), together with eighteen other constituents, including the sesquiterpenoids 1 and 2 , ent‐kaurane diterpenes 3 – 7 , triterpenoids 10 and 11 , steroids 12 – 14 , and flavonoids 15 – 17 as well as benzene derivatives 18 – 20 , were isolated from the aerial parts of Wedelia trilobata. The structures of wedelidins A ( 8 ) and B ( 9 ) were elucidated by extensive spectroscopic analyses (including UV, IR, NMR, and MS). Furthermore, the structures of compounds 2 and 3 were confirmed by X‐ray single‐crystal diffraction analyses.     

Diterpenes from the roots of Euphorbia kansui and their in vitro effects on the cell division of Xenopus (part 2)

Four new ingenane-type diterpenes, 3-O-(2,3-dimethylbutanoyl)-13-O-dodecanoyl-20-O-acetylingenol (1), 3-O-(2,3-dimethylbutanoyl)-13-O-dodecanoyl-20-deoxyingenol (2), 3-O-(2E,4Z-decadienoyl)-20-deoxyingenol (3), and 3-O-(2E,4E-decadienoyl)-20-deoxyingenol (4), two new jatrophane-type diterpenes, kansuinins D (9) and E (10), and four known ingenane-type diterpenes were isolated from the root of Euphorbia kansui. Their structures were elucidated by spectroscopic and chemical analysis, and individual Xenopus cells at the blastular stage were cultured with the diterpenes to test for biological activity. 20-Deoxyingenol diterpenes 3 and 4 induced the greatest cell cleavage arrest (0.5 micro g/ml of each compound resulted in >75% cleavage arrest), but cell cleavage inhibitory activity became weak when C-16 had an acyl residue. In contrast, the jatrophane diterpene kansuinin D (9) showed no activity.     

Studies on Chemical Constituents of Salix Matsudana

Two new phytane‐type diterpene‐γ‐lactones named Hanliuin III ( 3 ) and Hanliuin IV ( 4 ), together with two previously reported diterpenes, six known flavonoids and five other known compounds were isolated from Salix matsudana. The structures of two new compounds were deduced from spectroscopic methods and 2D NMR techniques.     

Two New Diterpenes from Solidago canadensis

Two new clerodane‐type diterpenes, solidagocanins A and B ( 1 and 2 , resp.), as well as two known compounds, mellein ( 3 ) and physcion ( 4 ), were isolated from the aerial parts of Solidago canadensis. The structures of the new compounds were elucidated by spectroscopic analyses, including 2D‐NMR techniques.     

ent‐Clerodanoids from Isodon scoparius

Three new ent‐clerodane diterpenoids, isoscoparin A, B, and C ( 1 – 3 ), were isolated from Isodon scoparius. Their structures were determined by NMR‐spectra analysis. The biogenetic implication of the diterpenes from Isodon genus is discussed.     

Natürlich vorkommende Terpen-Derivate, 59: Über neue Diterpene aus Dimorphotheca pluvialis Moench

Naturally Occurring Terpene Derivatives, 59: On New Diterpenes from Dimorphotheca pluvialis Moench. Besides small amounts of known acetylenes the investigated plant contains five new diterpenic acids ( 5 , 7 , 9 , 11 and 12 ), their structures being elucidated by spectroscopic methods. The relationship to these compounds to the diterpenes in other genera of the same tribe are discussed.     

Dimeric Diterpenes from the Roots of the Mangrove Plant Ceriops tagal

Three new dimeric diterpenes, tagalsin L ( 1 ), tagalsin M ( 2 ), and tagalsin N ( 3 ) were isolated from the roots of the mangrove plant Ceriops tagal. Their structures and relative configurations were elucidated by means of extensive IR, NMR, and MS analyses.     

Sarcophytonolides A–D,Four New Cembranolides from the Hainan Soft Coral Sarcophyton sp.

Four new cembranolide diterpenes, sarcophytonolides A–D ( 1 – 4 ), were isolated from a Hainan soft coral Sarcophyton sp. Their structures were elucidated on the basis of detailed spectroscopic analysis and by comparison with related model compounds.     

Further New Cembranoid Diterpenes from the Hainan Soft Coral Sarcophyton latum

Four new cembranoid diterpenes, sarcophytonolides I–L ( 1 – 4 ), were isolated from the Hainan soft coral Sarcophyton latum. Their structures were established by detailed analysis of 1D and 2D NMR spectra and by comparison with related model compounds.     

Three New, 1‐Oxygenated ent‐8,9‐Secokaurane Diterpenes from Croton kongensis

Three new ent‐8,9‐secokaurane diterpenes, kongensins A–C ( 1 – 3 ), were isolated from the aerial parts of Croton kongensis, together with two known compounds, rabdoumbrosanin ( 4 ) and (7α,14β)‐7,14‐dihydroxy‐ent‐kaur‐16‐en‐15‐one ( 5 ). The structures of the new compounds were elucidated by HR‐MS as well as in‐depth 1D‐ and 2D‐NMR analyses. Compounds 1 – 3 showed an unusual oxygenation pattern, with an AcO or OH group at C(1), in combination with a Δ⁸⁽¹⁴⁾ unsaturation ( 1 ) or an 8,14‐epoxide function ( 2, 3 ).     

Development of a comprehensive method for analyzing clerodane‐type diterpenes and phenolic compounds from Casearia sylvestris Swartz (Salicaceae) based on ultra high performance liquid chromatography combined with chemometric tools

This work describes the development and optimization of an analytical method utilizing liquid chromatography and chemometrics to evaluate and differentiate two varieties of Casearia sylvestris Swartz (Salicaceae) from São Paulo State (Brazil) based on their secondary metabolite profiles. Previously, analytical studies only concerned the analysis of clerodane‐type diterpenes. Therefore, considering the importance of including phenolic compounds in such analysis, we used design of experiments to simultaneously extract and detect the largest number of compounds from both chemical classes. This new strategy allowed a comprehensive chromatographic analysis of C. sylvestris, and the results for the two varieties exhibited an interesting distribution according to their original ecosystems, suggesting a strong correlation to the main metabolites found in each species group. Besides their inherent morphological differences, C. sylvestris variety lingua, mainly found in Cerrado areas, predominantly contains phenolic compounds, while C. sylvestris variety sylvestris, mainly found in Atlantic Forest areas, contains mostly clerodane‐type diterpenes. Finally, it was also possible to observe differences in the secondary metabolite composition within each group depending on the place where samples were collected.     

Acylated manoyl oxide diterpenes of Stemodia trifoliata

Two new labdane diterpenes, 6α‐malonyloxy‐ethyl ester manoyl oxide and bis‐6α‐dioxymanoylmalonate, together with the known 6α‐hydroxymanoyl oxide, 6α‐malonyloxymaloyl oxide and betulinic acid were isolated from leaves of Stemodia trifoliata. Their structures were elucidated by spectroscopic studies (IR and HR‐ESI‐MS), including an extensive NMR (COSY, HSQC, HMBC and NOESY) analysis. Copyright © 2010 John Wiley & Sons, Ltd.