Triterpenoids and a diterpene from Euphorbia iberica

From the aerial parts of Euphorbia iberica, an ingenane diterpene ester, ingenol 20-eicosanoate, and three ursanetype triterpenoids, 3beta-acetoxy-urs-12-ene-1beta,11alpha-diol, 3beta-( E)-coumaroyloxy-urs-12-ene, and 3beta-( Z)-coumaroyloxy-urs-12-ene have been isolated together with known cylcoartane-type triterpenes, a flavone, and coumarins. The first four compounds are new and their structures were determined by spectroscopic methods.     

Irritant and co-carcinogenic diterpene esters from the latex of Euphorbia cauducifolia L.

Ten (1–10) irritant and mild co-carcinogenic diterpene esters were isolated from the latex of Euphorbia cauducifolia L. using bioassay-guided countercurrent distribution and other chromatographic techniques. The isolated compounds were characterized on the basis of spectroscopic results and mass measurements. As an outcome, the ingenane-type esters were established with the following structures: 3-O-angeloyl-17-O-palmatoylingenol (1), 3-O-palmatoyl-5-O-angeloylingenol (2), 5-O-angeloyl-17-O-palmatoylingenol (3), 3-O-angeloyl-5-O-palmatoylingenol (4), 17-O-(2Z,4E,6Z)-2,4,6-tetradecatrienoyl-20-O-palmatoylingenol (5), 5-O-angeloyl-17-O-benzoylingenol (6), 5-O-angeloyl-17,20-diacetoxyingenol (7), 3-O-angeloyl-17-O-benzoyl-20-acetoxyingenol (8), 3-acetoxy-5-O-angeloyl-17-O-benzoylingenol (9), and 5-O-angeloyl-3,17,20-triacetoxyingenol (10). Their biological screening revealed that they are moderate irritants, and low to moderate tumor promoters compared to TPA, but hardly showed any solitary carcinogenic activity. The isolated esters represent new compounds and were not reported before from any source.     

Purification and characterization of a lectin from Euphorbia nivulia Buch. Ham. latex

A lectin from Euphorbia nivulia Buch. Ham. latex was purified by affinity chromatography on galactose-Sepharose-6B. Euphorbia nivulia latex (ENL-L) was resolved into four lectin fractions on CM-Sephadex C-50 column. All the four fractionated lectins were found to be homogeneous. One of the major fractionated lectins (ENL-L-IV) was further characterised. ENL-L-IV shows a single band on PAGE at pH 4.5 and SDS-PAGE. Both ENL-L and ENL-L-IV are glycoproleins containing 13.6% and 9% of carbohydrates respectively. ENL-L has a molecular weight of 45 700 and has two subunits with M_r of 19 000 and 22 800 and a sedimentation coefficient of 4S. ENL-L-IV has a molecular weight of 44 000 and appears to be a dimer with subunits of M_r of 22 000. Ultracentrifugation studies showed that it has a M_r of 29 000 and a sedimentation coefficient of 4.8S. Both ENL-L and ENL-L-IV are galactose specific and are also inhibited by galactose derivatives and its oligosaccharides. with increased β-anomeric specificity. They are found to be mitogenic against human lymphocytes and blood group non-specific. ENL-L-IV was found to be immunologically identical with ENL-L and other fractionated ENL lectins.     

Jatrophane diterpenes from the latex of Euphorbia obtusifolia with inhibitory activity on the mammalian mitochondrial respiratory chain

Seven diterpenes isolated of the latex of the Euphorbia obtusifolia were evaluated as inhibitors of the NADH oxidase activity in submitochondrial particles from bovine heart. Compound 2, 2,3,5,7,8,9,15-heptahydroxyjatropha-6(17),11-diene-14-one 8,9-diacetate 7-isobutyrate 2,3-bis(2-methylbutyrate), was the most potent inhibitor with an inhibitory concentration (IC 50 ) value of 5.1 +/- 0.2 microM. In the present study, some structure-activity trends are suggested for the inhibitory activity of these natural products on the mammalian mitochondrial respiratory chain.     

Absence of tumor promoting activity of Euphorbia milii latex on the mouse back skin

Euphorbia milii (Euphorbiaceae) is a decorative plant used in gardens and living fences. In China, it has also been employed in herbal remedies for hepatitis and abdominal edema. Since E. milii latex--lyophilized or in natura--proved to be a potent plant molluscicide, its toxicity to non-target organisms has been comprehensively studied. Concerns on a possible tumor promoting activity have discouraged its use as a locally-available alternative molluscicide in schistosomiasis control programs. Two in vitro assays (inhibition of metabolic cooperation in V79 cells and Epstein-Barr virus induction in Raji cells) had suggested that E. milii latex contained tumor-promoting substances. This study was undertaken to verify whether the latex acts as a tumor promoter in vivo as well. A single dose of the initiating agent DMBA (400 nmol) was applied on the back skin of male and female DBA/2 mice. Testing for tumor promoting activity began 10 days after initiation. Tetradecanoyl phorbol acetate (TPA) (5 nmol, positive control), lyophilized latex (20, 60 and 200 microg per mouse) or acetone (vehicle control) were applied on mouse back skin twice a week for 20 weeks. In TPA-treated mice, papillomas were firstly noted during the 11th week, and by the 17th week all animals exhibited skin tumors. No tumors developed in mice treated with the solvent alone and in those exposed to latex. Findings from the present study therefore indicated that E. milii crude latex does not act as a tumor promoting agent on the mouse back skin assay.     

Triterpenoids from Gouania ulmifolia

Two new triterpenoids, named gouanic acid A (1) and gouanic acid B (2), were isolated from the aerial parts of Gouania ulmifolia, along with six known compounds. The structures of the new compounds were determined by spectroscopic methods, mainly NMR (1D and 2D) and mass spectrometry. The new compounds did not show significant antimicrobial activities.     

Triterpenoids from Peganum nigellastrum

Two triterpenoids were isolated from the roots of Peganum nigellastrum Bunge. Their structures were elucidated as 3alpha-acetoxy-27-trans-caffeoyloxyolean-12-en-28-oic acid methyl ester (1) and 3-oxotirucalla-7, 24-dien-21-oic acid (2) on the basis of spectroscopic evidence. 1 is a new triterpene ester and 2 is a known compound isolated for the first time from genus Peganum.     

雷公藤三萜化合物结构研究

从雷公藤乙醇提取物中分得五个化合物,经光谱解析及相关化合物光谱对照确定其化学结构。其中化合物（1）鉴定为一新化合物,命名为3β,22α,30-三羟基-乌索-12-烯。     

Triterpenoids from Salvia wagneriana

From the exudate of Salvia wagneriana Polak, beside the known ursolic acid, two pentaoxygenated triterpenoids were isolated. Their structures were determined as 3-oxo-11alpha,19beta,20,22beta-tetrahydroxy-lupane (1) and 3beta,11alpha,19beta,20,22beta-pentahydroxy-lupane (2) using a combination of one- and two-dimensional NMR techniques.     

Triterpenoids from Viburnum betulifolium

Two new triterpenoids, ursa-12-sene-3β,11β-diol 3-O-palmitate (1) and ursa-12-sene-1β,3β,11α-triol 3-O-palmitate (2), were isolated from the 70% aqueous acetone extract of the aerial parts of Viburnum betulifolium, together with the artificial diene derivative of 2, ursa-12-dien-1β,3β-diol 3-O-palmitate (2a). Their structures were characterized by various spectroscopic methods, including 1D NMR, 2D NMR, and HR-ESI-MS.     

Triterpenoids from pyrethrum tatsienense

Two novel and eight known triterpenoids were isolated from alcoholic extract of the whole plant of Pyrethrum tatsienense. The structures of new compounds were elucidated as olean-12-en-3beta,11alpha,16beta-triol-3-O-palmitate (1), ursa-12-en-3beta,11beta,16beta-triol-3-O-palmitate (2) by spectroscopic methods including intensive 2D NMR techniques (H1-H1 COSY, gHMQC, gHMBC) and FAB-MS, and the known compounds were identified on the basis of comparing their NMR data with those of corresponding compounds in the literature.     

Triterpenoids from the roots ofRubus parvifolius

From the roots ofRubus parvifolius L., four triterpenoidal sapogenins, ursolic acid1, 2α-hydroxyursolic acid2, euscapic acid3, 2α, 3β, 19α-trihydroxyurs-12-en-23,28-dioic acid4 and one triterpenoidal glycoside, suavissimoside R₁ 5, were isolated. The structures were elucidated by spectroscopic methods and chemical transformations. Compound4 was first isolated as free form.     

Triterpenoids from the roots ofDipsacus asper

Four triterpenoids were isolated from the roots ofDipsacus asper. On the basis of chemical and spectral evidence, the structures of these compounds have been elucidated to be hederagenin (1), hederagenin 3-O-α-L-arabinoside (2). 3-O-α-L-arabinopyranosyl hederagenin 28-O-β-D-glucopyranosyl ester (3) and hederagenin 28-O-β-D-glucopyranosyl (1→6)-β-D-glucopyranosyl ester (4). The new glycoside,4, was named dipsacus saponin A.     

Triterpenoids from Walsura trichostemon

Bioactivity guided separation of Walsura trichostemon stem methanolic extract led to the isolation of four new dammarane (1–4) and two new apotirucallane triterpenoids (5–6), together with one limonoid (7), 11,25-dideacetyltrichostemonate, 12β, 20S, 24R-trihydroxydammar-25-en-3-one and 12β, 20S, 25-trihydroxydammar-23-en-3-one. Compounds 1–7 showed in vitro inhibitory activity on the proliferation of A549, human lung adenocarcinoma cell line.

     

Triterpenoids from Peganum nigellastrum

Two triterpenoids were isolated from the roots of Peganum nigellastrum Bunge. Their structures were elucidated as 3α-acetoxy-27-trans-caffeoyloxyolean-12-en-28-oic acid methyl ester (1) and 3-oxotirucalla-7, 24-dien-21-oic acid (2) on the basis of spectroscopic evidence. 1 is a new triterpene ester and 2 is a known compound isolated for the first time from genus Peganum.     

Triterpenoids from Viburnum betulifolium

Two new triterpenoids, ursa-12-sene-3β,11β-diol 3-O-palmitate (1) and ursa-12-sene-1β,3β,11α-triol 3-O-palmitate (2), were isolated from the 70% aqueous acetone extract of the aerial parts of Viburnum betulifolium, together with the artificial diene derivative of 2, ursa-12-dien-1β,3β-diol 3-O-palmitate (2a). Their structures were characterized by various spectroscopic methods, including 1D NMR, 2D NMR, and HR-ESI-MS.     

Triterpenoids from the stems of Myricaria paniculata

Two new pentacyclic triterpenoids myricarin A and B (1 and 2) have been isolated from the stems of Myricaria paniculata, together with seven known compounds, myriconal, 28-hydroxy-14-taraxeren-3-one, epi-friedelanol, β-sitosterol, 4-methyl stigmast-7-en-3-ol, 12-hentriacontanol and 1-triacontanol. Their structures have been established by chemical and spectroscopic methods. Cytotoxic activities of 1 and 2 have been evaluated against several different cell lines.     

大叶钩藤茎三萜类成分研究（英文）

从大叶钩藤茎中分离得到19个三萜类成分,包括11个乌苏烷型三萜和8个齐墩果烷型三萜,其化学结构通过波谱学方法鉴定。19个化合物中12个化合物为首次从大叶钩藤中分离得到,6个化合物为首次从钩藤属植物中分离得到。