Search results for "complement"
showing 10 items of 2113 documents
Enzymatic formation of the sarpagan-bridge: a key step in the biosynthesis of sarpagine- and ajmaline-type alkaloids.
1995
The glucoalkaloid strictosidine has been converted under cell-free conditions into 10-deoxysarpagine (= normacusine B) in the presence of a crude soluble enzyme extract and microsomal protein isolated from cell suspensions of Rauwolfia serpentina. The enzymatic formation of this alkaloid bearing the C-5/C-16 bond (sarpagan-bridge), which is characteristic for all sarpagine- and ajmaline-type alkaloids, is dependent on NADPH and oxygen. Inhibition studies indicate that for the synthesis of 10-deoxysarpagine a cytochrome P450 dependent monoxygenase is necessary.
Analysis of Essential Oil from Teucrium maghrebinum Greuter et Burdet Growing Wild in Algeria
2009
The chemical composition of the essential oil obtained from aerial parts of Teucrium maghrebinum growing wild in Algeria was analyzed by GC and GC-MS. Among the 66 identified compounds, δ-cadinene (12.7%), germacrene D (11.4%), γ-cadinene (9.5%) and 4-vinyl guaiacol (4.0%) were the most abundant. The oil is strongly characterized by the presence of sesquiterpenes (61.5%), particularly hydrocarbon sesquiterpenes (49.6%).
Steroidal saponins from Chlorophytum deistelianum
2016
Abstract Phytochemical investigation of the aerial parts of Chlorophytum deistelianum led to the isolation of four previously undescribed steroidal saponins called chlorodeistelianosides A–D with five known ones. Their structures were established mainly by extensive 1D and 2D NMR spectroscopic techniques and mass spectrometry as (25R)-3β-[(β- d -glucopyranosyl-(1 → 3)-[α- l -rhamnopyranosyl-(1 → 4)]-β- d -xylopyranosyl-(1 → 3)-[β- d -glucopyranosyl-(1 → 2)]-β- d -glucopyranosyl-(1 → 4)-β- d -galactopyranosyl)oxy]-5α-spirostan-12-one, (24S,25S)-24-[(β- d -glucopyranosyl)oxy]-3β-[(β- d -glucopyranosyl-(1 → 2)-[β- d -xylopyranosyl-(1 → 3)]-β- d -glucopyranosyl-(1 → 4)-β- d -galactopyranosyl)ox…
Triterpene Saponins from the Fruits of Phytolacca rugosa (Phytolaccaceae)
2010
Four known serjanic acid glycosides were isolated from the fruits of Phytolacca rugosa and characterized mainly by 2D NMR spectroscopy and mass spectrometry. This aglycon has a chemotaxonomic significance for the genus Phytolacca.
Antiproliferative oleanane saponins from Polyscias guilfoylei
2008
Three new oleanane saponins (1–3), together with four known ones (4–7), were isolated from the aerial parts of Polyscias guilfoylei. Their structures were elucidated by 1D and 2D NMR experiments, including 1D TOCSY, DQF-COSY, ROESY, HSQC, and HMBC spectroscopy, as well as ESIMS analysis. The antiproliferative activity of all compounds was evaluated using three murine and human cancer cell lines; J774.A1, HEK-293, and WEHI-164. All the compounds were inactive except for 3β- O-[β-D-glucopyranosyl-(1→2)-α-L-arabinopyranosyl]-echinocystic acid 28-[ O-β-D-glucopyranosyl-(1→6) O-β-D-glucopyranosyl] ester (3), which was active against all the cell lines.
New Diosgenin Glycosides from Costus afer
1997
Two new steroidal saponins, aferosides B (1) and C (2), together with the known saponins, dioscin (3) and paryphyllin C (4), were isolated from the roots of Costus afer. The known flavonoid glycoside, kaempferol 3-O-α-l-rhamnopyranoside (5), was obtained from the aerial parts. The structures of the new compounds were elucidated principally by 2D NMR spectral methods. A structural revision of the sugar sequence was made for the previously reported saponin aferoside A (6) on the basis of detailed spectroscopic analysis. Saponins 1−4 and 6 did not show any ability to potentiate in vitro cisplatin cytotoxicity in a human colon cancer cell line.
Neoclerodane Diterpenoids from Scutellaria polyodon
1997
Nine new neoclerodane diterpenoids, scupolins A−I, have been isolated from an Me2CO extract of the aerial parts of Scutellaria polyodon (3−11), together with the known neoclerodanes jodrellin B (1) and scutecolumnin A (2). Structures 3−11 were established by spectroscopic means and by comparison with closely related compounds.
Two New Oleanane-type Saponins from Hydrocotyle multifida
2018
A phytochemical study of a Venezuelan species Hydrocotyle multifida led to the isolation of five oleanane-type glycosides: two previously undescribed and three known ones. Their structures were established by 2D NMR spectroscopic techniques and mass spectrometry as 3- O-β-D-galactopyranosyl-(1→2)-[α-L-arabinopyranosyl-(1→3)]-β-D-glucuronopyranosyloleanolic acid and 3- O-β-D-glucopyranosyl-(1→2)-β-D-glucopyranosyl-(1→2)-β-D-glucuronopyrano-syloleanolic acid. These results represent a significative contribution to the chemotaxonomy of the Hydrocotyle genus.
8-NH2-Boldine, an Antagonist of α1Aand α1BAdrenoceptors without Affinity for the α1DSubtype: Structural Requirements for Aporphines at α1-Adrenocepto…
2005
Structure-activity analysis of 21 aporphine derivatives was performed by examining their affinities for cloned human alpha (1A), alpha (1B) and alpha (1D) adrenoceptors (AR) using membranes prepared from rat-1 fibroblasts stably expressing each alpha (1)-AR subtype. All the compounds tested competed for [ (125)I]-HEAT binding with steep and monophasic curves. The most interesting compound was 8-NH (2)-boldine, which retains the selective affinity for alpha(1A)-AR (pKi = 6.37 +/- 0.21) vs. alpha(1B)-AR (pKi = 5.53 +/- 0.11) exhibited by 1,2,9,10-tetraoxygenated aporphines, but shows low affinity for alpha(1D)-AR (pKi < 2.5). Binding studies on native adrenoceptors present in rat cerebral cor…
Neoclerodane Diterpenoids from Teucrium massiliense
1998
A reinvestigation of the diterpene metabolites of Teucrium massiliense L. allowed the isolation of four new neoclerodane derivatives, teumassilenins A-D, together with all the diterpenoids previously reported as constituents of this plant. The structures of the new compounds (1-4) were established by chemical and spectroscopic means. A plausible biogenetic relationship between several of these substances is briefly discussed, and some unpublished physical and spectroscopic data of the previously known diterpenoid teumassin (5) are now reported.