Five new labdane diterpenes from Aster oharai

Five new labdane diterpenes (1-5) together with seven known diterpenes have been isolated from a methanol extract of the aerial parts of Aster oharai. Five new structures were determined as 7alpha-hydroperoxylabda-8(17),14-dien-13(R)-ol-4-O-acetyl-alpha-L-6-deoxyidopyranoside (1), 7alpha-hydroperoxylabda-8,14-dien-13(R)-ol-4-O-acetyl-alpha-L-6-deoxyidopyranoside (2), labda-7,14-dien-13(R)-ol-4-O-acetyl-alpha-L-rhamnopyranoside (3), labda-7,14-dien-13(R)-ol-3-O-acetyl-alpha-L-rhamnopyranoside (4), and labda-7,14-dien-13(R)-ol-2-O-acetyl-alpha-L-rhamnopyranoside (5), on the basis of spectroscopic methods. Compound 1 showed moderate cytotoxicity against four cultured human tumor cell lines with ED(50) values ranging from 1.1 to 7.7 microg/mL.     

New furanoid diterpenes from Caesalpinia pulcherrima

Four new cassane-type furanoditerpenoids (1-4) were isolated from the air-dried leaves of Caesalpinia pulcherrima. Their structures were elucidated by spectral data interpretation. The exocyclic methylene compound 1 readily isomerized and oxidized to the benzofuran 4. Benzyl 2,6-dimethoxybenzoate (5) was also identified in this study. Antimicrobial tests on 1-5 indicated that they were active against several bacteria (S. aureus, E. coli, P. aeruginosa, and B. subtilis) and fungi (C. albicans and T. mentagrophytes).     

A new route toward 7-Oxo-13-hydroxy-8,11,13-podocarpatrienes from labdane diterpenes

Trinorlabdane 1,5-diketones (7, 10a,b, 13a,b), which are easily prepared from labdane diterpenes, are directly converted into the corresponding 7-oxo-13-hydroxy-8,11,13-podocarpatrienes, immediate precursors of bioactive compounds, under basic treatment. Utilizing this strategy, the first enantiospecific synthesis of 13-hydroxy-8,11,13-podocarpatriene (20), a constituent of Taiwania cryptomerioides, was achieved starting from (-)-sclareol (5) after a seven-step sequence in 55% overall yield.     

New brominated labdane diterpenes from the red alga Laurencia obtusa

Two labdane type brominated diterpenes (1 and 2) containing unprecedented eight- and seven-membered ether rings have been isolated from the organic extract of the red alga Laurencia obtusa, collected from Mitikas Bay in the Ionean Sea, Greece. The structures of the new natural products, as well as their relative stereochemistry, were established by means of spectral data analysis, including 2D NMR experiments.     

Cyclooxygenase (COX)-1 and -2 inhibitory labdane diterpenes from Crassocephalum mannii

Two new labdane diterpenes, 8alpha,19-dihydroxylabd-13 E-en-15-oic acid (1) and 13,14,15,16-tetranorlabdane-8alpha,12,14-triol (2), as well as an acetylated derivative, 8alpha-O-beta-D-glucopyranosyllabd-13 E-ene-15,19-diol-8alpha-2',3',4',6'-hexaacetate (3a), were isolated from the aerial parts of Crassocephalum mannii. The structures of 1, 2, and 3a were elucidated by spectroscopic data analysis. Selective inhibitory activity for 1 and 2 and their acetate derivatives, 1a and 2a, against cyclooxygenases (COX-1 and COX-2) was detected.     

Pacovatinins A-C, new labdane diterpenoids from the seeds of Renealmia exaltata

Three new labdane diterpenoids, pacovatinins A-C (1-3), were isolated from seeds of the Brazilian medicinal plant Renealmia exaltata ("Pacová-catinga"), and their structures including absolute configurations were elucidated by spectroscopic data and a modified Mosher method.     

Two new spongian diterpenes from Coscinoderma mathewsi

Two new spongian diterpenes were isolated from the sponge, Coscinoderma mathewsi. One possesses a tricyclic skeleton bearing an aldehyde function, the other is a tetracyclic lactol. The structures of two compounds are elucidated by spectral method.     

Tricholomalides A-C, new neurotrophic diterpenes from the mushroom Tricholoma sp

Three new diterpenes, tricholomalides A-C (1-3), were isolated from the methanol extract of the fruiting body of Tricholoma sp. Their structures were elucidated on the basis of their spectral data, and the absolute configuration of 1 was determined by CD spectrum. Tricholomalides 1-3 significantly induced neurite outgrowth in rat pheochromocytoma cells (PC-12) at concentrations of 100 microM.     

Briaexcavatolides K-N, new briarane diterpenes from the gorgonian Briareum excavatum

Four new briarane diterpenes, briaexcavatolides K-N (1-4), along with a known diterpene, 5, have been isolated from the Taiwanese gorgonian Briareum excavatum. The structures of the new metabolites were established by extensive spectral analyses. Furthermore, the structure, including the relative configuration of briaexcavatolide K (1), was confirmed by a single-crystal X-ray analysis. Briaexcavatolides K and L (1 and 2) are the only briarane diterpenes known to possess hydroxyl groups at the C-8beta and C-17alpha positions, respectively. Cytotoxicity of these metabolites toward various cancer cell lines also is described.     

Excavatolides F-M, new briarane diterpenes from the gorgonian Briareum excavatum

Eight new briarane-type diterpenes, excavatolides F-M (1-8), have been isolated from the gorgonian Briareum excavatum. The structures and relative stereochemistry of these compounds were established by spectral analysis and chemical methods. The cytotoxicity of these compounds toward various cancer cell lines has also been determined.     

Structure and antibacterial activity ofp6 new labdane diterpenoid from Salvia leriaefolia

Phytochemical investigation of the choloroform extract of Salvia leriaefolia afforded 8(17),12E,14-labdatrien-6,19-olide (1), and its structure was determined by a combination of spectral methods. Compound 1 was found to possess antibacterial activity against Staphylococcus aureus.     

Structure and absolute configuration of new diterpenes from Lavandula multifida

Four new diterpenes (1-4) have been isolated from the aerial parts of Lavandula multifida, together with the known compound glutinosin (5). The structures of these compounds were identified on the basis of extensive NMR studies as 15,16-dihydroxy-7,11-dioxopimar-8(9)-ene (1), 15S,16-dihyroxy-7-oxopimar-8(9)-ene (2), 15,16,17-trihydroxy-7-oxopimar-8(9)-ene (3), and 15,16,17-trihydroxypimar-8(9)-ene (4). The absolute configuration of the 15,16-diol moiety in 1-5 was determined observing the circular dichroism induced after addition of dimolybdenum tetracetate in DMSO solution.     

迷迭香中2个新松香烷型二萜化合物

目的研究迷迭香Rosmarinus officinalis的化学成分及其活性。方法采用多种柱色谱对迷迭香地上部分甲醇提取物进行分离纯化;通过波谱数据对化合物进行结构鉴定;采用磺酰罗丹明B比色法(SRB法)对所得化合物进行细胞毒活性测试。结果从迷迭香的甲醇提取物中分离得到2个新的松香烷型二萜类化合物和8个已知二萜类化合物,分别鉴定为7-异丙氧基-表异迷迭香酚(1)、7-异丙氧基-迷迭香醌(2)、迷迭香酚(3)、7-甲氧基-迷迭香酚(4)、表迷迭香酚(5)、7-甲氧基-表异迷迭香酚(6)、rosmaquinoneB(7)、鼠尾草酚(8)、galdosol(9)和pisiferal(10)。结论化合物1和2为新化合物,分别命名为7-异丙氧基-表异迷迭香酚和7-异丙氧基-迷迭香醌。活性测试结果表明所有二萜类化合物均无明显细胞毒活性。     

Six new spongian diterpenes from the sponge spongia matamata

Chemical investigation of the sponge Spongia matamata collected in Yap, Micronesia, has resulted in the isolation of six new spongian diterpenoids, 2-7, along with the known compound, spongia-13(16), 14-dien-19-oic acid (1). The structures were determined by spectroscopic methods.     

Two new ring A-rearranged clerodane diterpenes, dunniana acids A and B, from Clausena dunniana

Two ring A-rearranged clerodane diterpenes named dunniana acids A (1) and B (2) were isolated from the aerial parts of Clausena dunniana. The structures of 1 and 2 were determined using spectral methods.     

Neoclerodane and labdane diterpenoids from Plectranthus ornatus

Three new diterpenoids, a neoclerodane and two labdane derivatives, have been isolated from an acetone extract of Plectranthus ornatus. The structures of these compounds (plectrornatins A-C, 1-3, respectively) were established mainly by spectroscopic means, particularly by 1D and 2D NMR studies and, in the case of the neoclerodane 1, by an X-ray diffraction analysis. Compounds 1 and 3 showed moderate antimicrobial activity against five Candida species and selected Gram negative and Gram positive bacteria strains.     

覆盆子茎中1个新的半日花烷型二萜苷

目的 研究华东覆盆子Rubus chingii茎的化学成分。方法 利用硅胶、ODS柱色谱、Sephadex LH-20葡聚糖凝胶柱色谱、高效制备液相色谱等色谱方法进行分离纯化,根据理化性质及波谱数据分析鉴定化合物结构。结果 从覆盆子茎中分离得到17个化合物,分别鉴定为松脂素(1)、黑麦草内酯(2)、催吐萝芙木醇(3)、(-)-丁香脂素(4)、13E-对映-半日花烷-8(17),13-二烯-3β,15,18-三醇(5)、3β,18-di-hydroxy-manool(6)、(+)-儿茶素(7)、(-)-儿茶素(8)、邻苯二甲酸二丁酯(9)、goshonoside-F1(10)、3β-hydroxy-manool-18-O-β-D-glucoside(11)、goshonoside-F2(12)、goshonoside-F5(13)、goshonoside-F4(14)、goshonoside-F3(15)、goshonoside-F7(16)、异槲皮素(17)。结论 化合物11为新化合物,命名为覆盆子苷B;化合物6为新的天然产物,化合物1～4为首次从该植物中分离得到,化合物1～17为覆盆...     

A new labdane diterpenoid from Renealmia alpinia collected in the Suriname rainforest.

Continuation of a previous study on Renealmia alpinia resulted in the isolation of the new labdane diterpenoid 3, together with two known diterpenoids. The structure of the new diterpenoid was determined by a combination of NMR techniques and HRFABMS.