Bafoudiosbulbins A, and B, two anti-salmonellal clerodane diterpenoids from Dioscorea bulbifera L. var sativa

Two clerodane diterpenoids, Bafoudiosbulbins A 1, and B 2, together with five known compounds: tetracosanoic acid, 1-(tetracosanoyl)-glycerol, trans-tetracosanylferulate, beta-sitosterol and 3-O-beta-D-glucopyranosyl-beta-sitosterol were isolated from the tubers of Dioscorea bulbifera L. var sativa. Their structures were established by spectroscopic methods (1D and 2D-NMR, MS) and X-ray crystallographic diffraction analysis of compound 1. The CH2Cl2-soluble portion of the crude extract and the two clerodanes were screened for anti-bacterial activity using both agar diffusion and broth dilution techniques against Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus, Salmonella typhi, Salmonella paratyphi A and Salmonella paratyphi B. They both showed significant activities against P. aeruginosa, S. typhi, S. paratyphi A and S. paratyphi B.     

cis‐Clerodane Diterpenes from the Liverwort Scapania ciliata

Chemical investigation of the Chinese liverwort Scapania ciliata led to the isolation of four new cis‐clerodane lactones, named ciliatolides A–D ( 1 – 4 , resp.), among which compound 1 was found to be a tetranorclerodanoid. Their structures were determined by extensive analysis of spectroscopic data, and, in the case of compound 1 , together with a single‐crystal X‐ray diffraction analysis. The absolute configurations were established by analysis of the CD spectra and by quantum‐chemical CD calculations. The cytotoxicities of compounds 1 – 4 were preliminarily tested against the PC3 and MCF‐7 cell lines.     

New clerodane diterpenoids from Laetia procera (Poepp.) Eichler (Flacourtiaceae), with antiplasmodial and antileishmanial activities

Extracts of Laetia procera (Flacourtiaceae) displayed significant in vitro activity against Plasmodium falciparum. P. falciparum bioassay guided fractionation of a trunk bark extract of this plant led to the isolation of six clerodane diterpenoids (1-6) and a butanolide (7). Five of these compounds are new and called Laetiaprocerine A-D (3-6) and Laetianolide A (7). Their structures were established on the basis of 1D and 2D NMR experiments. Absolute configurations of 1 and 2 were determined by a modified Mosher's method and the absolute configuration of 5 by chemical correlation. The clerodane diterpenoids displayed activities against P. falciparum with an IC50 down to 0.5 microM on FCb1 and F32 strains, and also cytotoxicity toward human tumor cell line MCF7. The most active compound showed a selectivity index of 6.8. Some of these compounds also displayed activities against Leishmania amazonensis amastigote axenic stages and promastigote.     

Diterpene from Baccharis trimera with a relaxant effect on rat vascular smooth muscle

A bioassay monitored fractionation of a chloroform extract from the aerial parts of Baccharis trimera yielded a mixture that blocked the Ca2+-induced contractions of KCl- depolarized rat portal vein preparations. Pharmacological tests of two pure compounds isolated from the mixture revealed the dilactonic clerodane diterpene as the active compound.     

Casearin X,Its Degradation Product and Other Clerodane Diterpenes from Leaves of Casearia sylvestris: Evaluation of Cytotoxicity against Normal and Tumor Human Cells

An EtOH extract of the leaves of Casearia sylvestris afforded new clerodane diterpene, casearin X, together with the known compounds casearins B, D, L, and O, and caseargrewiin F. Casearin X degraded to the corresponding dialdehyde when stored in CDCl₃. The diterpenes isolated were cytotoxic to human cancer cell lines, with caseargrewiin F being the most active and the new clerodane, casearin X, the second active compound with IC₅₀ values comparable to the positive control doxorubicin. All isolated diterpenes showed lower activities against normal human cells than against cancer cell lines, which might indicate a possible selective action on cancer cells. Casearin X dialdehyde was not cytotoxic to cancer cells indicating that the occurrence of these CO groups at C(18) and C(19) is incompatible with the cytotoxic activity.     

Biotransformation of 16-oxacleroda-3,13(14)E-dien-15-oic acid isolated from Polyalthia longifolia by Rhizopus stolonifer increases its antifungal activity

Biotransformation of the antifungal compound 16-oxocleroda-3,13(14)E-dien-15-oic acid (1) isolated from Polyalthia longifolia leaves was achieved by Rhizopus stolonifer in broth medium containing the substrate at the sublethal concentration of 0.06?mg ml^?1. A novel derivative, 18-hydroxy-16-oxocleroda-3,13(14)E-dien-15-oic acid (2) was isolated after 4 d of incubation. Minimum inhibitory concentration (MIC) was determined against 11 fungal pathogens of clinical and agricultural importance. The biotransformed compound showed lower MIC values than the natural parent compound. The study showed that the fungus R. stolonifer has the potential to hydroxylate a natural fungicidal clerodane diterpene at allylic position to produce a novel hydroxylated derivative with enhanced antifungal activity.     

Neo-clerodane diterpenoids from Croton schiedeanus

Two new neo-clerodane type furano diterpenoids were isolated from the aerial part of Croton schiedeanus, besides the clerodane diterpenes cis- and trans-dehydrocrotonin, previously isolated from other species of Croton. Structural elucidation was achieved on basis of extensive NMR experiments, including X-ray diffraction analysis and molecular mechanics calculations. The previously known flavonoids ayanin and quercetin-3,7-dimethyl ether were also obtained from the extract of this plant.     

克罗烷二萜的昆虫拒食活性及构效关系研究

以饲料柱称重法测定25个克罗烷二萜新化合物对亚洲玉米螟Ostrinia furnacalis(Guenee)5龄幼虫的拒食活性,并进行构效关系分析。结果表明：立体效应对拒食活性意义 重大;C₉边链、C₁₈位的酯基对活性具有一定影响;C_{4处的螺环氧结构看来并非活性所必需。且在25μg/mL时选择法测定中,活性最高的化合物拒食率为57.9%,而500/μg/mL时非选择法测定中拒食率为43.2%。}     

Teupolin III,a furanoid diterpene from Teucrium polium

A new clerodane derivative was isolated from Teucrium polium var. polium. The structure and stereochemistry have been established by detailed studies of the ¹H NMR spectra.     

Cytotoxic clerodane diterpenoids from Croton crassifolius

Hepatocellular carcinoma (HCC) is the most common type of liver cancer, and treatment options for HCC are limited. In addition, the discovery of new natural compounds with anti-hepatocarcinoma activity is attracting increasing attention. For this reason, phytochemical investigation of Croton crassifolius led to the isolation of 17 diterpenoids, including three new clerodane diterpenoids, named crassifolius A-C (1–3), along with 14 known ones (4–17). Their structures were established by 1D, 2D NMR, HR-ESI-MS, detailed calculated electronic circular dichroism (ECD) spectra and the assistance of quantum chemical predictions (QCP) of ¹³C NMR chemical shifts. The cytotoxicities of all these compounds against human liver cancer lines (HepG2 and Hep3B) were determined. Among them, compound 1 exhibited good cytotoxicity with IC₅₀ value of 17.91 μM against human liver tumor cells Hep3B. Following further studies of the anti-tumor mechanism of compound 1-induced cell growth inhibition, we found that compound 1 caused apoptotic cell death in Hep3B cells by detecting morphologic changes and Western blotting analysis.     

Diterpenoids from the stem bark of Croton zambesicus

Three clerodane diterpenoids, crotozambefurans A, B and C were isolated from the stem bark of Croton zambesicus together with the known clerodane crotocorylifuran and two trachylobanes: 7 beta-acetoxytrachyloban-18-oic acid and trachyloban-7 beta, 18-diol. Betulinol, lupeol, sitosterol and its 3 beta-glucopyranosyl derivative were also obtained. The structures of crotozambefurans A, B and C were determined, respectively, as: 15,16-epoxy-1,3,13(16),14-clerodatetraen-20,12-olide-18,19-dioic acid dimethylester, 15,16-epoxy-1,3,13(16),14-clerodatetraen-18,19,20-trioic acid trimethylester and 15,16-epoxy-3,13(16),14-clerodatrien-19,1 alpha:20,12-diolide-18-oic acid methylester, using spectroscopic analysis, especially, NMR spectra in conjunction with 2D experiments, COSY, HSQC, HMBC and TOCSY.     

Cordatin,a new diterpene from Aparisthmium cordatum

A new furano diterpene, cordatin, with a clerodane skeleton has been isolated from the bark of Aparisthmium cordatum. Its molecular structure has been investigated by spectroscopic means and by X-ray analysis.     

Clerodane diterpenoids from Teucrium and Ajuga plants

A new clerodane diterpenoid, chamaepitin has been isolated from Ajuga chamaepitys. The previously known clerodanes, 19-acetylgnaphalin, auropolin, teucrin A and teuflin, have been isolated from Teucrium species (T. polium subsp. belion, T. polium subsp. capitatum and T. asiaticum) collected in Majorca. X-ray diffraction analysis on crystals of auropolin has allowed the assignment of configuration at C-20 as S for this compound.     

Cytotoxic diterpenoids as potential anticancer agents from the twigs of Casearia kurzii

A search for bioactive natural products as anticancer lead compounds has led to the isolation of five new clerodane diterpenoids (1–5) from the twigs of Casearia kurzii. Their structures were elucidated by extensive analysis of their NMR, IR, and HRESIMS data, and the absolute configurations were determined by experimental and calculated electronic circular dichroism (ECD) data analysis. The isolates were biologically evaluated and showed cytotoxic activities toward human lung cancer cells (A549), human cervical cancer cells (HeLa), and human hepatocellular carcinoma cells (HepG2). The most active compound (5) with an IC₅₀ value of 5.3 μM against HeLa cells, was found to induce apoptosis and arrest the HeLa cell cycle at G0/G1 stage to exert cytotoxic effects.     

Clerodanes and other constituents of Cleidion spiciflorum

The polyoxygenated clerodane, spiciflorin (1a), was isolated from Cleidion spiciflorum (Burm. f.) Merr. (Euphorbiaceae). Other constituents were the glucoside of anol (2), columbin, scopoletin, 3,3',4-O-trimethylellagic acid, acetylaleuritolic acid, common triterpenes and phenols.     

Diterpenes with a new carbon skeleton from Printzia Laxa

The aerial parts of the South African composite Printzia laxa contain two manoyl oxides and three clerodane derivatives together with two further acids, which belong to a new type of diterpene, biogenetically closely related to the clerodanes. The structures have been elucidated by spectroscopic methods. The constituents may indicate some relationship of Printzia to the tribe Astereae.     

宽叶泽苔草萜类化学成分分析及其化学分类学意义

宽叶泽苔草Caldesia grandis隶属泽泻科Alismataceae,是一种珍稀濒危水生植物。其化学成分迄今未见报道。本文利用气质联用的方法鉴定了该植物的43种化学成分,并总结了已报道的其近缘泽泻属Alisma、慈姑属Sagittaria、刺果泽泻属Echinodorus植物的化学成分,据此进行化学分类学分析:它们的特征化学成分是二萜,宽叶泽苔草和泽泻属植物的二萜成分是处于二萜生源合成途径最顶端的kaurane类型;慈姑属植物的二萜成分既有处于该途径底端的clerodane型、中间的pimarene型,也有顶端的kaurane型、abietene型二萜;刺果泽泻属植物的二萜成分是处于该途径底端的clerodane型。宽叶泽苔草和泽泻属植物都有桉叶烷型和愈创木烷型的倍半萜。因此宽叶泽苔草和泽泻属植物的亲缘关系比慈姑属、刺果泽泻属植物的近,由此推测它们的进化层次可能依次是刺果泽泻属植物、慈姑属植物、泽泻属植物、宽叶泽苔草。     

Cytotoxic clerodane diterpenes from Glossocarya calcicola

Three clerodane diterpenes were isolated and identified from leaf extract of Glossocarya calcicola. Compound has been characterised as (rel)-10betaH-trans-12xi-(2-methylbut-2(E)-enoyl)-1beta-(isobutanoyl)-6alpha,13xi-dihydroxyclerodan-4(20),8(18)-dien-7,15-dione-15,16-oxide, to which we have assigned the trivial name calcicolin-A. The other two compounds had the same skeletal structure and C-12 substituent but in compound, the C-1 esterifying group becomes 2-methylbut-2(E)-enoic acid and in it becomes 2-methylbutanoic acid. Although anti-insect activity was not observed for G. calcicola, cytotoxicity against insect and human carcinoma cell lines was detected.     

Aparisthman,methyl 1-(3-furoylmethyl)-4a-hydroxy-1,2-dimethyl-2,3,4,4a,5,8,9,9a-octahydro-1H-benzocycloheptene-6-carboxylate,a seven membered ring diterpenoid from Aparisthmium cordatum

A new diterpenoid, aparisthman, with a rearranged clerodane skeleton has been isolated from the bark of Aparisthmium cordatum. Its molecular structure has been investigated by spectroscopic means and by X-ray analysis.     

Clerodane diterpene glucosides from Tinospora rumphii

Seven new diterpene glucosides of the clerodane type were isolated from the stems of Tinospora rumphii. Among the seven, one was isolated as an acetyl derivative. The structures of these compounds were established by the application of various spectroscopic techniques.