共查询到20条相似文献,搜索用时 15 毫秒
1.
Yong Zhao Sheng-Xiong Huang Li-Sheng Ding Xian Li Han-Dong Sun 《Tetrahedron letters》2009,50(17):2019-6066
A phytochemical investigation of Isodon pharicus led to the isolation of a novel asymmetric ent-kauranoid dimer, bispseurata F (1), and three new diterpenoids, pharicinins A-C (2-4). Their structures were elucidated by extensive spectroscopic analysis. Compound 1 features a unique linkage pattern of C-17 with C-11′ to connect the two monomers. A possible biogenetic pathway of 1 was also proposed. Compounds 3 and 4 exhibited moderate inhibitory activity against NB4 and SH-SY5Y cell lines. 相似文献
2.
Hai-Bo Zhang Xue Du Yuan-Yuan Wang Yong Zhao Xiao Luo Yan Li 《Tetrahedron letters》2010,51(32):4225-4228
Two novel diterpenoids, luanchunins A (1) and B (2), along with their precursor, kamebakaurin (3), had been isolated from the stems and leaves of Isodon rubescens var. lushanensis. Their structures were elucidated on the basis of extensive spectroscopic analyses. Compounds 1 and 2 showed potent cytotoxic activity against HL-60 with IC50 values of 4.81 μM and 3.52 μM, respectively. Plausible pathways for the biosynthesis of 1 and 2 were also postulated. 相似文献
3.
Two novel tricyclic diterpenoids rubescensins U (1) and V (2) were isolated from the leaves of Isodon rubescens var. taihangensis. They were elucidated as a 8,15-seco-ent-kauranoid and an ent-abietanoid, respectively, by 1D and 2D NMR spectra, and single crystal X-ray analysis. Compound 1 is the first example of an 8,15-seco-ent-kaurane from the plants genus Isodon. A discussion of their biogenesis is described. 相似文献
4.
Three novel asymmetric ent-kaurane dimers xindongnins M-O (1-3) were isolated from Isodon rubescens var. rubescens. Their structures were elucidated by spectroscopic methods including 2D NMR analysis. The relative stereochemistry of 1 was determined by single crystal X-ray diffraction, which also confirmed the unique linkage of a single carbon-carbon bond between the two subunits of this dimer. A biogenetic pathway was proposed for the formation of these dimers. 相似文献
5.
Sheng-Xiong Huang Yan Zhou Rong-Tao Li Wei-Lie Xiao Quan-Bin Han Shu-Lin Peng 《Tetrahedron》2006,62(20):4941-4947
An extensive study of the diterpenoids produced by the species of Isodon rubescens, has led to the isolation of 12 new ent-kaurane diterpenoids, hebeirubescensins A-L (1-12), and 19 known analogues. Their structures were determined on the basis of spectroscopic analysis. Selected compounds were assayed for their inhibitory ability against human A549, HT-29, and K562 cells. Among them, hebeirubescensins B and C exhibited significant cytotoxicity with IC50 values of <2.0 μM. The structure-activity relationships were discussed. 相似文献
6.
Li-Bin Yang Jing Yang Chun Lei Yong Zhao Sheng-Xiong Huang Quan-Bin Han Han-Dong Sun 《Tetrahedron letters》2008,49(22):3574-3577
Bisjaponins A (1) and B (2), two new dimeric ent-kaurane diterpenoids connected with a rare four-membered carbon ring, which was formed by [2+2] reaction, were isolated from the aerial parts of Isodon japonicus. Their structures were elucidated by the analysis of spectroscopic evidence including extensive 2D NMR and MS data. Both the compounds were inactive for their cytotoxicity against human tumor cell lines, K562 and HepG2. 相似文献
7.
Koichi Nishimura Noriko Sugeta Kazuya Fujita Yutaka Aoyagi Takeshi Kinoshita Hideaki Otsuka Koichi Takeya 《Tetrahedron》2006,62(7):1512-1519
Six rearranged ent-kaurane diterpenes, tricalysiolides A-F, having the cafestol-type carbon framework were isolated from the wood of Tricalysia dubia (Rubiaceae). Their absolute structures were determined on the basis of the 2D NMR spectroscopy, X-ray crystallographic analysis, and chemical methods. 相似文献
8.
A novel asymmetric ent-kauranoid dimer, lushanrubescensin J (1), was isolated from Isodon rubescens var. lushanensis. Its structure was elucidated by the spectroscopic evidences. The stereochemistry was confirmed by the single crystal X-ray diffraction of its tetraacetate. Compound (1) exhibited potent inhibitory activity against K562 cells with IC50 = 0.93 μg/mL. 相似文献
9.
Wei-Guang Wang Bing-Chao Yan Xiao-Nian Li Xue Du Hai-Yan Wu Rui Zhan Yan Li Jian-Xin Pu Han-Dong Sun 《Tetrahedron》2014
Twenty nine 6,7-seco-ent-kaurane-type diterpenoids including 18 new ones, laxiflorolides C–T (1–18), along with 21 known ones were obtained from Isodon eriocalyx var. laxiflora. Laxiflorolides E–G (3–5) are the first identified naturally occurring 6,7-seco-ent-kauranoids that feature a 3,6-epoxy unit, and laxiflorolide M (11) is the first identified naturally occurring 6-nor-6,7-seco-ent-kauranoid. The absolute configurations of compounds 1, 3, 6, and 11 were determined by single-crystal X-ray diffraction analyses. The cytotoxic activity of the isolates was evaluated by an MTT assay. 相似文献
10.
A synthesis and stereochemistry confirmation of a constituent recently isolated from the whole plant Isodon excisus is reported. An enantioselective catalytic boron-mediated reduction of an α-bromoketone was utilized in the key synthetic transformation. The methodology described herein was also used for the synthesis of the natural product's enantiomer and several derivatives. In addition, the compounds were evaluated for inhibitory activity in a caspase induction assay. The natural product was found to be devoid of activity, but several derivatives had moderate inhibitory activity (EC50<1 μM). 相似文献
11.
Li-Mei Li Guo-You Li Li-Sheng Ding Chun Lei Li-Bin Yang Yong Zhao Zhi-Ying Weng Sheng-Hong Li Sheng-Xiong Huang Wei-Lie Xiao Quan-Bin Han Han-Dong Sun 《Tetrahedron letters》2007,48(52):9100-9103
Three new 6,7-seco-ent-kauranoids (1–3) were isolated and structures were elucidated from Isodon sculponeatus. Diterpenoids 1–3 possessing multicyclic skeletons formed via oxygen atoms are all unprecedented among ent-kauranes. Compound 1 displayed significant cytotoxic activity against K562, A549, and HepG2 human tumor cell lines, with IC50 values of 1.4, 2.3, and 2.0 μM, respectively, equal to the positive control. Plausible pathways for the biosynthesis of 1 and 2 from one related diterpenoid were also postulated. 相似文献
12.
Jian-Fan Sun Hui Huang Xing-Yun ChaiXian-Wen Yang Li MengCai-Guo Huang Xue-Feng ZhouBin Yang Jing HuXian-Qiang Chen Hui LeiLishu Wang Yonghong Liu 《Tetrahedron》2011,67(6):1245-1250
Five new briarane type diterpenoids, dichotellides A−E (1−5), were isolated from the South China Sea gorgonian Dichotella gemmacea together with four known analogues (6−9). Compounds 1−5 represent the first examples of iodine-containing briarane type diterpenoids from nature. The structures of these diterpenoids were elucidated by spectroscopic analysis, including 1D, 2D-NMR, and HRESIMS, and the absolute configuration of 1 was further confirmed by single crystal X-ray diffraction analysis. All the isolates were evaluated for cytotoxicity activity against four human tumor cell lines, and only 3 exhibited marginal activity against SW1990 (human pancreatic cancer). 相似文献
13.
Chemical investigation of the soft coral Cespitularia hypotentaculata resulted in the isolation of eight new diterpenes, cespihypotins E-L (1-8). The new metabolites comprise of six verticillene-type diterpenes, one cespitularane derivative, and one derivative with 14-membered lactone ring. The structures were determined through detailed spectroscopic analyses, especially high resolution ESIMS and 2D NMR techniques. The relative stereochemistry was deduced from NOESY spectrum and application of Mosher's ester technique. Immunomodulatory and antiviral activities of 1-8 were tested and evaluated. The biogenetic pathways for 1-8 were also proposed. 相似文献
14.
Susumu Kawakami Hideaki Otsuka Takakazu Shinzato Masatoshi Kawahata 《Tetrahedron letters》2010,51(33):4320-4322
From the stems of Croton cascarilloides collected in the Okinawa Islands, a structurally rare crotofolane-type diterpenoid (1) and a rearranged nor-crotofalane, a new skeletal diterpenoid (2) were isolated. The structures were determined by X-ray crystallographic analyses, establishing their absolute stereostructures for the first time. Compound 2 was probably biosynthesized from 1 through several steps, such as decarboxylation, oxidation, C-C bond migration. 相似文献
15.
Ping-Jyun Sung Yu-Pei Chen Tsong-Long Hwang Lee-Shing Fang Yang-Chang Wu Jyh-Horng Sheu 《Tetrahedron》2006,62(24):5686-5691
Four new briarane-related diterpenoids, designated as briaexcavatins C-F (1-4), were isolated from the Formosan octocoral Briareum excavatum, collected off southern Taiwan coast. The structures of these new metabolites were elucidated by the interpretation of spectroscopic and chemical methods. The configuration of 1 was further supported by molecular mechanics calculations. Briarane 1 has been shown to exhibit mild cytotoxicity toward MDA-MB-231 human breast tumor cells and briarane 3 was found to show activity to inhibit neutrophil elastase release in humans. 相似文献
16.
Two new diterpenoids, 6β-(2-methylbut-2(Z)-enoyl)-3α,4α,15,16-bis-epoxy-8β,10βH-ent-cleroda-13(16),14-dien-20,12-olide and 10β-hydroxy-6-oxo-3α,4α,15,16-bis-epoxy-8βH-cleroda-13(16),14-dien-20,12-olide, together with the known β-amyrin, spinasterol, 5,7-dihydroxy-3,8,3′,4′-tetramethoxyflavone and 5,7-dihydroxy-3,8,3′,4′,5′-pentamethoxyflavone have been isolated from the aerial parts of Microglossa angolensis Oliv. et Hiern (Compositae). The structures were elucidated on the basis of spectral studies and comparison with published data. 相似文献
17.
An Okinawan soft coral Cespitularia sp. has proven to be a good source of cytotoxic metabolites having a carbon skeleton of the seco-type variety of xenicin. This soft coral yielded alcyonolide, the major constituent, and other related compounds, all of which have proven to be cytotoxic. Reinvestigation of the cytotoxic ethyl acetate extracts of the coral yielded two new alcyonolide congeners, trisnorditerpenoid 1 and diterpenoid 2, possessing the same carbon skeleton. Their structures were elucidated by a detailed analysis of spectroscopic data (1D, 2D NMR, and MS). Metabolites 1 and 2 showed cytotoxicity against HCT116 cells (IC50 6.04 and 47.0 μM, respectively) and a dose dependent, anti-inflammatory effect in LPS/IFN-γ-stimulated inflammatory RAW 264.7 macrophage cells. 相似文献
18.
Miwa Yoshinaga 《Tetrahedron》2004,60(36):7861-7868
Five new dimeric Cephalotaxus alkaloids, bis-cephalezomines A-E (1-5), have been isolated from the leaves of Cephalotaxus harringtonia var. nana, and the structures and stereochemistry were elucidated on the basis of spectroscopic data including 2D NMR and FABMS/MS spectra, and chemical means. 相似文献
19.
Hai-Bo Zhang Jian-Xin Pu Yong ZhaoFei He Xiao-Nian LiXiao Luo Li-Guang LouHan-Dong Sun 《Tetrahedron letters》2011,52(46):6061-6066
A phytochemical investigation of Isodon leucophyllus led to the isolation of four novel ent-kauranoid dimers: bisleuconins A-D (1-4), and one known compound, rabdoloxin A (5). It was interesting that the structures of bisleuconins A (1) and B (2) were elucidated as a pair of epimeric ent-kauranoid dimers with unique linkage pattern C-16→C-17′ to connect two monomers. Bisleuconins C (3) and D (4) were two new asymmetric ent-kauranoid dimers. A possible biogenetic pathway of 1 and 2 was also proposed. 相似文献
20.
A novel compound, named sinutriangulin A (1), was isolated from the soft coral Sinularia triangula. The compound possesses a new carbon skeleton that is derived from the cubitane skeleton. The structure was determined by extensive spectroscopic analyses. In addition, compound 1 exhibited weak cytotoxicity toward human tumor cell lines CCRF-CEM and DLD-1. 相似文献