排序方式: 共有124条查询结果,搜索用时 109 毫秒
31.
Hong Zhao Cheng Wu Weng Xin Tian Peng Xiang Lai Jian Jun Huang Wei Dong Xie 《中国化学快报》2010,21(5):613-615
<正>A novel eremophilane dimer,named fischelactone(1),was isolated from the roots of Ligularia fischeri.Complete structural elucidation of this compound was performed by HRESIMS,IR,1D NMR and 2D NMR(~1H-~1H COSY,HMBC,HMQC and NOESY) data. 相似文献
32.
Jyh‐Horng Wu Yi‐Fu Chang Yu‐Tang Tung Minoru Tsuzuki Akira Izuka Sheng‐Yang Wang Yueh‐Hsiung Kuo 《Helvetica chimica acta》2010,93(4):753-756
Two novel 15(10→1)abeomuurolane sesquiterpenes, cosmosoic acid ( 1 ) and cosmosaldehyde ( 2 ), were isolated from the whole plant of Cosmos sulfurous. Their structures were established by a combination of 1D‐ and 2D‐NMR spectroscopic techniques. Additionally, a chemical correlation between 1 and 2 was also established. 相似文献
33.
A new compound was elucidated as 9-acetyl-6-caryophyllen-15-ol. Iridoid glucosides including catalpol, methyl catalpol, 7-deoxy-8-epiloganic
acid, and aucubin, were isolated from leaves of Buddleia parviflora, while the known compounds were identified as dehydrobuddledin A and buddledin C. The structures was elucidated by extensive
1D-2D-NMR spectroscopy.
Published in Khimiya Prirodnykh Soedinenii, No. 1, pp. 29–31, January–February, 2008. 相似文献
34.
The comparative study between the theoretical molecular properties of the starting materials and the yields in the transformation of melampolides to cis,cis-germacranolides using SeO2/t-BuOOH (TBHP) as oxidant allows to establish a feasible relationship with their values of dipolar moment. Conditions for this transformation are optimized and some mechanistic considerations are made based in this finding. Cluster analysis of the phytotoxic activity of the melampolides and cis,cis-germacranolides obtained shows that the activity is greatly influenced by the spatial shape of the backbone, prevailing upon other factors such as the presence of reactive functional groups. 相似文献
35.
Chromatographic investigation of an acetone extract of the octocoral Xenia puerto‐galerae afforded three new cadinene sesquiterpenes; 8‐epi‐xenitorin A ( 1 ), 10‐epi‐xenitorin C ( 2 ), and 7‐isopropenyl‐4,10‐dimethyl‐2,3,4,5‐tetrahydronaphthalene ( 3 ), in addition to four known cadinene analogs ( 4 , 11–13 ) and six xenicanes ( 5–10 ). The structures were elucidated through spectroscopic analysis, especially 2D NMR. A biogenetic pathway of 1–3 and analogs was proposed. 相似文献
36.
Narcy Arizmendi Syed Benazir Alam Khalid Azyat Darren Makeiff A. Dean Befus Marianna Kulka 《Molecules (Basel, Switzerland)》2022,27(8)
Sesquiterpenes (SQs) are volatile compounds made by plants, insects, and marine organisms. SQ have a large range of biological properties and are potent inhibitors and modulators of inflammation, targeting specific components of the nuclear factor-kappaB (NF-κB) signaling pathway and nitric oxide (NO) generation. Because SQs can be isolated from over 1600 genera and 2500 species grown worldwide, they are an attractive source of phytochemical therapeutics. The chemical structure and biosynthesis of SQs is complex, and the SQ scaffold represents extraordinary structural variety consisting of both acyclic and cyclic (mono, bi, tri, and tetracyclic) compounds. These structures can be decorated with a diverse range of functional groups and substituents, generating many stereospecific configurations. In this review, the effect of SQs on inflammation will be discussed in the context of their complex chemistry. Because inflammation is a multifactorial process, we focus on specific aspects of inflammation: the inhibition of NF-kB signaling, disruption of NO production and modulation of dendritic cells, mast cells, and monocytes. Although the molecular targets of SQs are varied, we discuss how these pathways may mediate the effects of SQs on inflammation. 相似文献
37.
Jamile Silva da Costa Waldemir Magno S. Andrade Raphael O. de Figueiredo Paulo Vinicius L. Santos Jofre Jacob da Silva Freitas William N. Setzer Joyce Kelly R. da Silva Jos Guilherme S. Maia Pablo Luis B. Figueiredo 《Molecules (Basel, Switzerland)》2022,27(7)
Myrciaria (Myrtaceae) species have been well investigated due to their chemical and biological relevance. The present work aimed to carry out the chemotaxonomic study of essential oils of the species M. dubia, M. floribunda, and M. tenella, sampled in the Brazilian Amazon and compare them with the volatile compositions from other Myrciaria species reported to Brazil and Colombia. The leaves of six Myrciaria specimens were collected (PA, Brazil) during the dry season, and their chemical compositions were analyzed by gas chromatography-mass spectrometer (GC-MS) and gas chromatography-flame ionization detector (GC-FID). The main compounds identified in the essential oils were monoterpenes with pinane and menthane skeletons, followed by sesquiterpenes with caryophyllane and cadinane skeletons. Among the sampled Myrciaria specimens, five chemical profiles were reported for the first time: profile I (M. dubia, α-pinene, 54.0–67.2%); profile II (M. floribunda, terpinolene 23.1%, α-phellandrene 17.7%, and γ-terpinene 8.7%); profile III (M. floribunda, γ-cadinene 17.5%, and an unidentified oxygenated sesquiterpene 15.0%); profile IV (M. tenella, E-caryophyllene 43.2%, and α-humulene 5.3%); and profile V (M. tenella, E-caryophyllene 19.1%, and caryophyllene oxide 41.1%). The Myrciaria chemical profiles showed significant variability in extraction methods, collection sites, plant parts, and genetic aspects. 相似文献
38.
Information on naturally occurring aromatic mono-, sesqui-, and diterpenes was systematized. The types of their biological
activity and possible practical applications were described. Possible synthetic pathways to the most important terpenes were
examined.
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Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 3–13, January–February, 2006. 相似文献
39.
LiJingFANG ChenXiZHANG JinChunCHEN GuoJunZHENG YuLinLI 《中国化学快报》2005,16(5):569-571
A facile synthetic route to two seco-eudesmane, 4, 5-dioxo-10-epi-4, 5-seco-γ-eudesmane (1) and 4, 5-dioxo-10-epi-4, 5-seco-γ-eudesmol (2) from ( )-dihydrocarvone has been described. Avoiding expensive reagents, this highly economic method especially suits for the synthesis of 4, 5-seco-eudesman-type and ophianon-type sesquiterpenes with a double bond at position 11 and 12. 相似文献
40.
Identification of an Asexual Reproduction Inducer of Phytopathogenic and Toxigenic Fusarium
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Prof. Jianhua Qi Yushi Hirata Naoki Ushida Prof. Zhonghua Ma Prof. Hiroyuki Osada Prof. Toshio Nishikawa Dr. Lan Xiang 《Angewandte Chemie (International ed. in English)》2018,57(27):8100-8104
Asexual and sexual reproduction are the most important biological events in the life cycle of phytopathogenic and toxigenic Fusarium and are responsible for disease epidemics. However, the signaling molecules which induce the asexual reproduction of Fusarium are unknown. Herein we describe the structure elucidation, including the absolute configuration, of Fusarium asexual reproduction inducer (FARI), a new sesquiterpene derivative, by spectroscopic analysis, total synthesis, and conidium‐inducing assays of synthetic isomers. We have also uncovered the universality of FARI among Fusarium species. Moreover, a mechanism‐of‐action study suggested that the Gpmk1 and LaeA signaling pathways are required for conidium formation induced by FARI; conversely, the Mgv1 of mitogen‐activated protein kinase is not involved in conidium formation. FARI exhibited conidium‐inducing activity at an extremely low dose and high stereoselectivity, which may suggest the presence of a stereospecific target. 相似文献