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31.
Investigations on growth inhibition in Helianthus annuus led to the isolation of a new sesquiterpene lactone, a germacranolide with an α-methylene-γ-lactone moiety. The structure of this new germacranolide, annuithrin, was elucidated by spectroscopic methods. Its biological activity has been proven by growth inhibition in straight growth tests, antibacterial tests and inhibition of DNA-/RNA-synthesis in cells of the ascitic form of Ehrlich carcinoma. 相似文献
32.
Two diterpene carboxylic acids, one a new kaurenoid derivative and one the previously characterized labdane, ()-cis-ozic acid, as well as a 相似文献
33.
The aerial parts of Xanthium orientale afforded an isomer of xanthanol. 相似文献
34.
35.
The aerial parts of P. canadensis afforded a new germacran-8,12-olide and several diterpenic acids. The stereochemistry of the lactone could be established only by careful 1H NMR investigations of the corresponding pyrazolines formed by addition of diazomethane, while the natural compound and its acetate only show very uncharacteristic NMR spectra. The diterpenes all belong to the rare isokaurene type. The chemotaxonomic aspects are discussed briefly. 相似文献
36.
Four coumarins and seven isoprenoid compounds have been identified in potato tubers infected with Phoma exigua var. foveata. Among these were the 7-O-β-D-glucopyranoside of 7-hydroxy-6,8-dimethoxycoumarin (isofraxidin) and the sesquiterpene 2-(11,12-dihydroxy-11-methylethyl)-6,10-dimethyl-spiro[4,5]dec-6-en-8-one and its 12-O-β-D-glucopyranoside, which apparently have not been previously identified in potato tubers. At least two diastereoisomers of the latter glucoside were present. Analysis of eight fluorescent compounds in different parts of infected potatoes was performed by an improved HPLC technique. 相似文献
37.
Ovatifolin and two new sesquiterpene lactones, deacetylovatifolin and arturin (1β-hydroxy-8β-angeloyloxy-eudesmane-4(15),11(13)-diene-6α,12-olide, have been isolated from stems and leaves of Podanthus mitiqui. Two of these compounds showed cytotoxic activity. 相似文献
38.
Ferdinand Bohlmann Christa Zdero Robert M. King Harold Robinson 《Phytochemistry》1980,19(12):2663-2668
The investigation of three Eremanthus species afforded, in addition to known compounds, several new sesquiterpenelactones, a cumambrin B isobutyrate, four lactones related to the eremantholides, two to zexbrevin and one to goyazensolide. Furthermore, a new coniferyl alcohol derivative was isolated. The overall picture of the genus is very uniform. The occurrence of eremanthine and germacranolides with a furanone ring seems to be especially typical. 相似文献
39.
Investigation of the North American species Psilostrophe villosa afforded, in addition to known compounds, five new sesquiterpene lactones, which all turn out to be modified pseudoguaianolides, most of them closely related to hymenolide. However, one of the lactones is a new type of nor-pseudoguaianolide. Furthermore a new monoacetylated borneol-β-D-glucoside is present. The chemotaxonomic situation is discussed briefly. 相似文献
40.