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91.
A new germacranolide, novanin (I), has been isolated from Artemisia nova and its structure determined. The compound is also present in small amount in A. tripartite Rydb. ssp. rupicola Beetle. 相似文献
92.
William C. Burnett Samuel B. Jones Tom J. Mabry William G. Padolina 《Biochemical Systematics and Ecology》1974,2(1):25-29
Larval feeding tests were run to determine the preference of six species of Lepidoptera for two species of Vernonia which produce sesquiterpene lactones and one which has lost the ability to produce these bitter principles. Significant differences between the feeding preferences of the insect species were observed. Further feeding tests were run with a Vernonia leaf powder medium to determine how interspecific chemical differences influenced these preferences. The sesquiterpene lactone, glaucolide-A, was found to reduce larval feeding when incorporated in a Vernonia powder-agar medium. The amount of insect feeding was inversely proportional to the concentration of glaucolide-A in the medium. 相似文献
93.
《Bioscience, biotechnology, and biochemistry》2013,77(5):1120-1122
Flavoglaucin, its derivatives, and pyranonigrins, which are antioxidants produced by the molds used in fermented foods, were examined for their inhibition of tumor promotion by the Epstein-Barr virus early antigen activation test. Flavoglaucin and its derivatives exhibited high activity. Flavoglaucin and such a derivative as isodihydroauroglaucin inhibited mouse skin tumor promotion in a two-stage carcinogenesis test and appear to be antitumor promoters. 相似文献
94.
95.
Extraction of Helianthus pumilus L. furnished the antileukemic germacradienolide desacetyleupaserrin which was isolated in crystalline form and the relatively rare flavone nevadensin (5,7-dihydroxy -6,8,4trimethoxyflavone). 相似文献
96.
Abstract The role of calcium during the synthesis, secretion and molecular organization of the primary cell-wall polysaccharides is the topic of this review. With the exception of callose synthase, the in vitro activity of all polysaccharide synthases is not controlled by Ca2+ ions. However, changes in the intracellular Ca2+ level could control the rate of exocytotic fusion of the secretory vesicles containing cell-wall matrix polysaccharides. In particular, the ability of Ca2+ to regulate the fusion of secretory vesicles with the plasma membrane is due to a class of Ca2+-dependent phospholipid-binding proteins known as annexins. The ionic interactions between calcium and the negatively charged homogalacturonan domains of the pectins are important not only for the mechanical properties of the wall but also for the gel-properties of these complex biopolymers. 相似文献
97.
Two new sesquiterpene lactones, artelavanolides A ( 1 ) and B ( 2 ), and four known sesquiterpene lactones ( 3 – 6 ) were isolated from the leaves of Artemisia lavandulaefolia. Their structures were elucidated based on the analysis of spectroscopic data (1D, 2D‐NMR and HR‐ESI‐MS). The absolute configuration of 1 was determined by the analysis of single‐crystal X‐ray diffraction data. Artelavanolide A ( 1 ) is a rare sesquiterpene lactone possessing an unusual skeleton with the linkage of Me(14)–C(1) that is probably formed through a rearrangement of the guaiane‐type sesquiterpenoids. Artelavanolide B ( 2 ) is a new highly unsaturated guaianolide. Compounds 1 – 6 were tested for activities on the inhibition of COX‐2 enzyme in vitro. All of compounds exhibited inhibitory activity against COX‐2 with IC50 values ranging from 43.29 to 287.07 μm compared with the positive control, celecoxib (IC50 = 18.10 μm ). Among them, 3 showed the best COX‐2 inhibitory activity with an IC50 value of 43.29 μm . 相似文献
98.
One new furanoheliangolide derivative, 4,5-dihydroniveusin A, as well as the known compounds niveusin B and argophyllin A and B, were isolated from a Texas population of Helianthus annuus. Three previously characterized diterpene acids, grandifloric acid, ciliaric acid and 17-hydroxy-ent-isokaur-15(16)-en-19-oic acid were the principal constituents of this population. 相似文献
99.
Investigation of the ‘tea’ prepared from the leaves of ‘zoapatle’ (Montanoa tomentosa), resulted in the isolation of the known biologically active oxepane diterpenoids zoapatanol and montanol, the known sesquiterpene lactones zoapatanolide A, C and D as well as two new biologically active oxepane diterpenoids and a new sesquiterpene lactone. The structures of the new compounds were established by spectroscopic methods. 相似文献
100.
Ferdinand Bohlmann Laxmi N. Misra Jasmin Jakupovic Robert M. King Harold Robinson 《Phytochemistry》1985,24(9):2029-2036
Investigation of the aerial parts of Balsamorhiza sagittata afforded 12 new sesquiterpene lactones, five guaianolides, three heliangolides, three germacranolides and two geranylnerol derivatives. From the roots eight cycloartane derivatives, a hydroxylanosterone and hexacos-1-ene were isolated. Structures were elucidated mainly by spectroscopic methods, especially high field NMR. The chemotaxonomic situation is discussed briefly. 相似文献