Triterpenoids from Parthenium argentatum x P. tomentosa

Four tetracyclic triterpenoids and lupeol were isolated from the hybrid Parthenium argentatum x P. tomentosa. The new triterpenoids were identified as 16, 24-epoxy-3α-hydroxylanost-8-ene (argentatin E); 16, 24-epoxy-25-hydroxycycloart-1, 11, 22-trien-3-one (argentatin F); 16,24-dihydroxycycloart-20, 25-dien-3-one (argentatin G) and 16, 24-dihydroxycycloart-25-en-3-one (argentatin H). The chemical identities of these compounds were confirmed by the different spectrometric measurements.     

Synthesis of argentatin A derivatives as growth inhibitors of human cancer cell lines in vitro

The syntheses of nine argentatin A analogs are described. These compounds were assessed for their ability to inhibit growth in vitro in four human cancer cell lines. Our results showed that the presence of either a double bond at C-1/C-2, or a bromine atom or formyl moiety at C-2 as well as the presence of an isoxazol ring in argentatin A enhanced its potency in all cell lines tested. In addition, an X-ray study of (16S,17R,20S,24R)-3-oxime-20,24-epoxy-16,25-dihydroxy-cycloartan-3-one led to the determination of the correct stereochemistry of argentatin A.     

Synthesis and comparative molecular field analysis (CoMFA) of argentatin B derivatives as growth inhibitors of human cancer cell lines

Synthesis, characterization, anticancer activity, and comparative molecular field analysis (CoMFA) of 14 argentatin B (1) analogs are described. The effect of argentatin B derivatives on the growth of K562 (leukemia), PC-3 (prostate), U251 (CNS), and HCT-15 (colon) human cancer cell lines was determined using the sulforhodamine B test. The most active compound in this series, 2-formyl-(16beta,24R)-16,24-epoxy-25-hydroxycycloart-1-en-3-one (12), was about 35-50 times more potent than argentatin B (1). Structures were built using the X-ray crystallography of six derivatives for 3D modeling with Sybyl6.9. CoMFA of Log (1/IC50) in K562 cell line gave q2 = 0.507, r2 = 0.907, and three components. The standard deviation CoMFA contours indicate that increased activity is associated with a bulky group at C-2, a C1-C2 double bond, and low electronic density at C-25. Experimental Log P values for argentatin B and one derivative were 1-2 Log units more hydrophilic than the calculated CLog P values.     

Two serratane triterpenes from the stem bark of Picea jezoensis var. hondoensis

Two serratane triterpenoids were isolated from the stem bark of Picea jezoenis var. hondoensis, together with two known compounds, 3β-methoxyserrat-14-en-21-one and 3β-methoxyserrat-14-en-21α-ol. The serratane triterpenoids were characterized as 14β,15β-epoxy-3α-methoxyserratan-21β-ol and 3α-methoxy-21β-hydroxyserrat-14-en-16-one, on the basis of chemical and spectroscopic evidence.     

Triterpenoids from Tripterygium wilfordii

The extract (T(II)) of Tripterygium wilfordii Hook f. afforded four triterpenoids: wilforic acid D (3beta,24-epoxy-2alpha-hydroxy-24R*-ethoxy-29-friedelanoic acid); (E) 3beta,24-epoxy-2-oxo-3alpha-hydroxy-29-friedelanoic acid; (F) 2beta-hydroxy-3-oxo-friedelan-29-oic acid; 29-hydroxy-3-oxo-olean-12-en-28-oic acid and 17 known triterpenoids. Their structures were established on the basis of spectroscopic studies. In a bioactivity analysis, only the known dulcioic acid compound showed a significant inhibitory effect on cytokine production.     

Microbiological and chemical transformations of argentatin B

Argentatin B is a naturally occurring tetracyclic triterpene isolated from Parthenium argentatum x P. tomentosa. It was microbiologically transformed to 16, 24-epoxycycloartan-3alpha, 25-diol, (isoargentatin D), by Nocardia corallina var. taoka ATCC 31338, Mycobacterium species NRRL B3683 and Septomyxa affinis ATCC 6737. The later microbe also produced 16, 24-epoxycycloartan-3beta, 25-diol (argentatin D) and 1, 2-didehydroargentatin B, (isoargentatin D). Sodium hydroxide converted argentatin B to argentatin D and isoargentatin D. Hydrochloric acid treatment gave cycloartan-25-ol-3, 24-dione. Cerium sulfate/sulfuric acid/aqueous methanol induced scission of the isopropanol moiety and provided an isomeric mixture of 24-methoxy-25-27-trinorargentatin B. Oxidation of this isomeric mixture with pyridinium chlorochromate, selectively, attacked the isomer with the equatorial proton at position-24 to give the corresponding lactone, 24-oxo-25-27-trinorargentatin B. The produced compounds were characterized by spectroscopic methods.     

Tirucallane triterpenoids from Dysoxylum hainanense

Four tirucallane derivatives, 3beta,22S-dihydroxy-tirucalla-7,24-dien-23-one, 22,23-epoxy-tirucalla-7-ene-3beta,24,25-triol, 3beta,25-dihydroxy-tirucalla-7,23-diene, 23,26-dihydroxy-tirucalla-7,24-dien-3-one, together with two known triterpenoids, 24,25-epoxy-3beta,23-dihydroxy-7-tirucallene, tirucalla-7,24-diene-3beta,23-diol, were isolated from Dysoxylum hainanense. Their structures were elucidated on the basis of spectroscopic evidence.     

Chemical constituents of leaves and stem bark of Plumeria obtusa

The continued studies on the constituents of the fresh leaves and stem bark of Plumeria obtusa Linn. have led to the isolation and characterization of four new triterpenoids, dammara-12,20(22)Z-dien-3-one (1), dammara-12,20(22)Z-dien-3beta-ol (2), olean-12-en-3beta,27-diol (3), and 27-hydroxyolean-12-en-3-one (4) and 12 known compounds, which included eight triterpenoids; dammara-3beta,20(S),25-triol (5), urs-12-en-3beta-hydroxy-27-Z-feruloyloxy-28-oic acid (6), 3beta-hydroxyolean-12-en-28-oic acid (7), 3beta,27-dihydroxylupan-29-ene (8), 3beta-hydroxylupan-29-en-28-oic acid (9), 3beta-hydroxyursan-12-en-28-oic acid (11), 3beta-hydroxy-27-p-coumaroyloxy-olea-12-en-28-oic acid (12) and urs-12-en-3-one (15); an iridoid 1alpha-plumieride (10); a cardenolide 3alpha,14beta-dihydroxy-17beta-card-20(22)-enolide (13); a fatty acid ester methyl n-octadecanoate (14) and a steroid 3beta-hydroxy-delta5-stigmastane (16). The new constituents were characterized through spectroscopic studies including 1D (1H and 31C NMR) and 2D (COSY-45, NOESY, J-resolved, HMQC and HMBC) NMR and chemical transformations. This is the first report on the isolation of dammarane triterpenoids from P. obtusa. Compounds 5 and 6 are hitherto unreported from P. obtusa. The known compounds were identified by comparison of their spectral data with those reported in the literature.     

Microbial thansformation of a mixture of argentatin A and incanilin

The biotransformation of a mixture of argentatin A (20%) 1 and incanilin (80%) 2 by Gibberella suabinetti ATCC 20193 and Septomyxa affinis ATCC 6737 demonstrated the conversion of incanilin to 16beta-hydroxylanosta-2, 8, 23-triene, while argentatin A did not react. The acetate of this triterpenoid mixture was biotransformed by Septomyxa affinis ATCC 6737 to give five metabolites. Argentatin A acetate was transformed to 3beta, 16beta,30-trihydroxycycloart-20, 24-diene, 20R, 24R-epoxy-16beta, 25-dihydroxy-3, 4-seco-cycloart-4(28)-en-3-oic acid acetate and 20R, 24R-epoxy-16beta, 25-dihydroxy-3, 4-seco-cycloart-4(28)-en-3-oic acid. Incanilin acetate was converted to 16beta-hydroxylanosta-2, 8, 23-triene and 20R, 24R-epoxy-16beta, 25-dihydroxy-3, 4-seco-lanost-1, 4(28), 8-trien-3-oic acid acetate. The structural elucidations of these metabolites were achieved by different spectroscopic methods.     

Triterpenoids,lignans and a benzofuran derivative from the bark of Aglaia elaeagnoidea

One 1H-cyclopentatetrahydro[b]benzofuran, two lignans, two dammarane triterpenoids and one limonoid were isolated from the bark of Aglaia elaeagnoidea. The structures of the isolated compounds were established on the basis of spectral data. The lignan trans-2,3-bis(3,4,5-trimethoxybenzyl)-1,4-butanediol diacetate and 20S,24S-epoxy-25-hydroxymethyldammarane-3-one are new compounds. trans-3,4-Bis(3,4,5-trimethoxybenzyl)tetrahydrofuran has been synthesized, but not previously reported as a natural product.     

Triterpenoids from Gentiana scabra

Five triterpenoids, (20S)-dammara-13(17),24-dien-3-one, (20R)-dammara-13(17),24-dien-3-one, chirat-16-en-3-one, chirat-17(22)-en-3-one and 17beta,21beta-epoxyhopan-3-one, were isolated from the rhizomes and roots of Gentiana scabra together with five known ones, chiratenol, hop-17(21)-en-3-one, hop-17(21)-en-3beta-ol, lupeol and alpha-amyrin. The structures of new compounds were elucidated on the basis of spectroscopic studies.     

格木中新的三萜化合物(英文)

A phytochemical investigation of the bark of Erythroph/eum fordii Oliv. furnished five compounds.One is a new triterpenoid, namely 20S, 24S-epoxy-23S, 25-dihydroxy-dammarane-3-one (1), and four areknown, identified to be 20S, 25-epoxy-24R-hydroxydammarane-3-one (2), 20S, 24S-epoxydammarane-3β,25-diol (3), betulinic acid (4), morolic acid acetate (5). All the known compounds were isolated from thespecies for the first time. The structure of compound 1 was elucidated on the basis of spectroscopicanalyses.     

Flavaglines and triterpenoids from the leaves of Aglaia forbesii

Three structurally complex flavaglines of the cyclopenta[bc]benzopyran type, named desacetylpyramidaglains A, C, D (1-3), and the triterpene 23, 24, 25-trihydroxycycloartan-3-one (4) were isolated from the leaves of Aglaia forbesii together with the two rare pregnane steroids 2beta,3beta-dihydroxy-5alpha-pregn-17(Z)-en-16-one and 2beta,3beta-dihydroxy-5alpha-pregn-17(E)-en-16-one, as well as the bisamide pyramidatine, the sesquiterpene spathulenol, and the widespread triterpenoids lupeol, lupenone, and a mixture of beta-sitosterol and stigmasterol. Their structures were elucidated by 1D and 2D NMR spectroscopy and mass spectrometry. Compounds 3, 4, 5, and 6 were tested for antituberculosis and antiviral activity.     

格木中新的三萜化合物

对豆科格木属植物格木(Erythrophleum fordii Oliv.)树皮的乙醇提取物进行药理筛选,结果表明,对KB(人口腔上皮癌)、A2780(人卵巢癌)细胞具有较强的选择性抑制作用.从该醇提物的乙酸乙酯萃取部分分得一个新化合物和4个已知化合物,经光谱鉴定为20S 24S-环氧-23S,25-二羟基达玛烷-3-酮(1)、20S,25-环氧-24R-羟基达玛烷-3-酮(2)、20S,24S-环氧-达玛烷-3β,25-二醇(3)、白桦酸(4)和乙酰莫绕酸(5).     

Antibacterial diterpenes and their fatty acid conjugates from rice leaves

Six structurally oryzalide-related compounds, oryzadione (1), 2, 3, 4, 5 and 6, were isolated from a neutral fraction of the extract of healthy leaves using a bacterial leaf blight-resistant cultivar of a rice plant, "Norin-27", as a group of antimicrobial substances. Their structures were determined by spectroscopic studies to be kaurane analogues and kaurane analogues conjugated with fatty acids, i.e., 1: ent-15,16-epoxy-kauran-2,3-dione (enol form: ent-15,16-epoxy-2-hydroxy-kauran-1-en-3-one), 2: ent-15,16-epoxy-3beta-hydroxy-kauran-2-one, 3: ent-15,16-epoxy-3-oxa-kauran-2-one, 4: ent-15,16-epoxy-3beta-myristoyloxy-kauran-2-one, 5: ent-15,16-epoxy-3alpha-palmitoyloxy-kauran-2-one, and 6: ent-15,16-epoxy-2beta-palmitoyloxy-kauran-2-one.     

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.     

Labdane diterpenes from Leonurus japonicus leaves

Three labdane diterpenes 15,16-epoxy-6-hydroxylabda-5,8,13(16),14-tretraen-7-one (leojaponin), (9alpha,13S);15,16-diepoxy-7beta-hydroxylabd-14-en-6-one (13-epi-preleoheterin), and (9alpha,13R);15,16-diepoxy-6beta-hydroxylabd-14-en-7-one (iso-preleoheterin) were isolated from the leaves of Leonurus japonicus, in addition to the previously reported preleoheterin. The structure elucidations were made based on analysis of their spectroscopic data.     

Cycloartanes from Lindheimera texana

The following new cycloartanes were isolated from the aerial parts of Lindheimera texana: (16S,23S)- and (16S,23R)-16,23-epoxycycloart-24-en-3-one, (3S,16S,23S)- and (3S,16S,23R)-16,23-epoxycycloart-24-en-3ol, (16S,23R)-16,23-epoxy-23,25-epidioxycycloartan-3-one, (16S)-23,24,25,26,27-pentanorcycloartan-3-one-16,22-olide, (16S,23S,24R)- or (16S,23R,24S)-23,24-epoxycycloartan-3-one-16,25-diol and (16S,23ζ,24ζ)-cycloartan-3-one-16,23,24,25-tetrol. Structures were established by chemical transformations and spectroscopic methods and, in the case of (16S,23R)-16,23-epoxy-23,25-epidioxycycloartan-3-one, by X-ray crystallography. Norambreinolide, several known labdanes and oleanolic acid were also isolated.     

Two insecticidal tetranortriterpenoids from Azadirachta indica

Two new triterpenoids, 6 alpha-O-acetyl-7-deacetylnimocinol [24,25,26,27-tetra-norapotirucalla-(apoeupha)-6 alpha-acetoxy-7 alpha-hydroxy-1,14,20,22-tetraen-21,23-epoxy-3-one] (1) and meliacinol [24,25,26,27-tetranorapotirucalla-(apoeupha)-1 alpha-trimethylacryloxy-21,23-6 alpha,28-diepoxy-16-oxo-17-oxa-14,20,22-trien-3 alpha,7 alpha-diol] (2) were isolated from the methanolic extract of the fresh leaves of Azadirachta indica (neem). Their structures have been elucidated through spectral studies, including 2D-NMR (COSY-45, NOESY, HMQC and HMBC). The bioactivity of these as well as of nimocinol, reported earlier from the same source, is reported. The first compound and nimocinol showed toxicity on fourth instar larvae of mosquitoes (Aedes aegypti) with LC50 values of 21 and 83 ppm, respectively. The second compound had no effect upto 100 ppm.     

Anti-HIV-1 protease triterpenoids from Stauntonia obovatifoliola Hayata subsp. intermedia

Three triterpenoids, 16beta-hydroxy-2,3-seco-lup-20(29)-ene-2,3-dioic acid (1), 3beta,21beta,24-trihydroxy-30-noroleana-12,20(29)-dien-28-oic acid (2) and 16beta-hydroxylupane-1,20(29)-dien-3-one (3), along with eleven known triterpenes were isolated from stems of Stauntonia obovatifoliola Hayata subsp. intermedia (Y.C. Wu) T. Chen. Their structures were determined by analysis of HR-EI/FAB-MS and 1D and 2D NMR spectroscopic data and comparison with those in the literature. Ten of the compounds showed inhibitory activity against HIV-1 protease.