Showing papers on "Indole alkaloid published in 2004"
TL;DR: The greater than 300‐fold increase in tryptophan levels observed in these studies under certain induction conditions compares favorably with the fold increases obtained in previous constitutive expression studies, suggesting that terpenoid indole alkaloid levels are tightly controlled.
Abstract: Different plant species produce a variety of terpenoid indole alkaloids, which are of interest as plant defensive secondary metabolites and as valuable pharmaceuticals. Although significant progress has been made, the mechanisms regulating the levels of this important class of compounds require continued elucidation. Previous precursor feeding studies have indicated that alkaloid accumulation can be improved during the exponential growth phase of hairy root cultures through enhanced tryptophan availability. To test this relationship, transgenic hairy root cultures of Catharanthus roseus were established with a glucocorticoid-inducible promoter controlling the expression of an Arabidopsis feedback-resistant anthranilate synthase alpha subunit. Enzyme assays demonstrated that the Arabidopsis alpha subunit is compatible with the native beta subunit and that anthranilate synthase activity is more resistant to tryptophan inhibition in induced than in uninduced extracts. The metabolic effects of expressing the feedback-resistant anthranilate synthase alpha subunit were also dramatic. Over a 6-day induction period during the late exponential growth phase, tryptophan and tryptamine specific yields increased from almost undetectable levels to 2.5 mg/g dry weight and from 25 microg/g to 267 microg/g dry weight, respectively. The greater than 300-fold increase in tryptophan levels observed in these studies under certain induction conditions compares favorably with the fold increases obtained in previous constitutive expression studies. Despite the large increases in tryptophan and tryptamine, the levels of most terpenoid indole alkaloids were not significantly altered, with the exception of lochnericine, which increased 81% after a 3-day induction period. These results suggest that terpenoid indole alkaloid levels are tightly controlled.
85 citations
TL;DR: The results indicated that KOK1679 and My295, highly and moderately aphid‐resistant varieties, had a high indole alkaloid content during vegetative growth and during reproduction growth, respectively.
Abstract: Indole alkaloid contents of five winter wheat varieties at different growth stages, and the relationship between indole alkaloids and carboxylesterase activities of Sitobion avenae (F.) from wheat ears of different varieties were studied. The results indicated that KOK1679 and My295, highly and moderately aphid-resistant varieties, had a high indole alkaloid content during vegetative growth. During their reproduction growth, resistant varieties had a high alkaloid content in penultimate leaves, and indole alkaloid contents of KOK1679 were significantly higher than that of other varieties in wheat ears. The indole alkaloid contents of all varieties were low in flag leaves except for Han4564. A significant correlation was shown between carboxylesterase activity in aphids collected from wheat ears and indole alkaloid contents in ears of the wheat varieties (r = 0.9646).
59 citations
TL;DR: A new indole alkaloid, akuammiginone (1), and a new glycosidic indole acid, echitamidine-Noxide 19-O-β-d-glucopyranoside (2), together with the five known alkaloids (echitaminic acid (3), echITamidine Noxide (4), Nb-demethylalstogustine N-oxide (5), Akuammicine Noxoxide (6), and Nb -demethyl alstog
Abstract: A new indole alkaloid, akuammiginone (1), and a new glycosidic indole alkaloid, echitamidine-N-oxide 19-O-β-d-glucopyranoside (2), together with the five known alkaloids, echitaminic acid (3), echitamidine N-oxide (4), Nb-demethylalstogustine N-oxide (5), akuammicine N-oxide (6), and Nb-demethylalstogustine (7), were isolated from the trunk bark of Alstonia scholaris collected in Timor, Indonesia. The structures of all compounds were elucidated by spectroscopic methods. This is the first report of compounds 3−5 and 7 in A. scholaris. Some NMR assignments of the known compounds were revised.
57 citations
TL;DR: The effect of different growth regulators on growth and the production of terpenoid indole alkaloids as well as some enzymes involved in the biosynthesis were studied in Catharanthus roseus seedlings.
Abstract: The effect of different growth regulators on growth and the production of terpenoid indole alkaloids as well as some enzymes involved in the biosynthesis were studied in Catharanthus roseus seedlings. The seedlings were grown on MS solid medium containing different concentrations of each growth regulator for a period of one month. Extracted alkaloids were analyzed by HPLC for determination of terpenoid indole alkaloid quantities. Continuous availability of growth regulators induced different alkaloids with variable effects among the regulators. Gibberellic acid at concentration of either 5.8 μM or 11.6 μM resulted in elongation of shoots with lowering the number of leaves. Abscisic acid has a retardant effect on growth. Ethylene did not effect the growth pattern at concentration of 100 μM but seedlings were not tolerant to higher concentrations. Methyljasmonate reduced the growth of the root system. Methyljasmonate was a general inducer for all alkaloids and increased the activity of strictosidine glucosidase. Ethylene applications promoted the pathways towards ajmalicine, serpentine, tabersonine and vindoline. Similar effect as for ethylene was observed for abscisic acid. Salicylic acid treatment increased the production of serpentine, tabersonine and higher concentration of salicylic acid induced vindoline accumulation. Peroxidase activity was also induced by salicylic acid. Gibberellic acid has little effect on alkaloid levels.
55 citations
TL;DR: Using the Pictet-Spengler reactions of tryptophan with aldehydes under acidic conditions at ambient temperature, diastereoisomers of 1,3-disubstituted-1,2,3,4-tetrahydro-β-carbolines could readily be furnished in short time (0.5-4h) with good yields (50-98%) as discussed by the authors.
50 citations
TL;DR: In this article, two indole alkaloids, angustilodine (1) with an unprecedented pentacyclic carbon skeleton, and Angustilocine (2), belonging to the seco-angustilobine-B group of alkaloid, were obtained from the leaf extract of the Malayan species Alstonia angustilioba, and their structures were established by spectroscopic analysis.
Abstract: Two new indole alkaloids, angustilodine (1), with an unprecedented pentacyclic carbon skeleton, and angustilocine (2), belonging to the seco-angustilobine-B group of alkaloids, were obtained from the leaf extract of the Malayan species Alstonia angustiloba, and their structures were established by spectroscopic analysis.
23 citations
TL;DR: A new yohimbine-type indole alkaloid was isolated from the stem bark of Mitragyna africanus (WILLD.) collected in Nigeria, along with known seven Corynanthe-type oxindole alkAloids, two secoiridoids, three lignans, and a quinovic acid derivative.
Abstract: A new yohimbine-type indole alkaloid (1) was isolated from the stem bark of Mitragyna africanus (WILLD.) collected in Nigeria, along with known seven Corynanthe-type oxindole alkaloids, two secoiridoids, three lignans, and a quinovic acid derivative. Their structures were elucidated by spectroscopic analyses.
22 citations
TL;DR: A novel indole alkaloid, nauclefolinine (1) and five known triterpenic compounds, rotundic acid (2), a -L-rhamnoquinovic acid (3), 3- O - b -D-glucopyranosyl- b -sitosterol (4 ), squalene (5 ) and sitosterol-3- O 6'stearoyl-b -D -glucophyranoside (6) have been isolated from the roots of Nauclea latifolia RE
Abstract: A novel indole alkaloid, nauclefolinine ( 1 ) and five known triterpenic compounds, rotundic acid ( 2 ), a -L-rhamnoquinovic acid ( 3 ), 3- O - b -D-glucopyranosyl- b -sitosterol ( 4 ), squalene ( 5 ) and sitosterol-3- O -6’-stearoyl- b -D-glucopyranoside ( 6 ) have been isolated from the roots of Nauclea latifolia . KEY WORDS: Nauclea latifolia , Rubiaceae, Indole alkaloid, Triterpenic acids, Rotundic acid, Rhamnoquinovic acid Bull. Chem. Soc. Ethiop. 2003 , 17(2), 173-176.
14 citations
TL;DR: The first enantiospecific total synthesis of the indole alkaloid (+)-dehydrovoachalotine (1) has been achieved from d -(+)-tryptophan methyl ester in 28% overall yield as mentioned in this paper.
12 citations
TL;DR: The bis-indole alkaloid arundavine, a tryptamine-tryptamine base, was isolated from roots of Arundo donax as mentioned in this paper.
Abstract: The new bis-indole alkaloid arundavine, a tryptamine-tryptamine base, was isolated from roots of Arundo donax. The dimer consists of monomeric units of two known indole alkaloids, alline and bufotenine, joined through the N1 and C4′ atoms, respectively, to give the structure 8-[3-(2-dimethylaminoethyl)-5-hydroxy-1H-indol-4-yl]-1-methyl-2,3,8,8a-tetrahydro-1H-pyrrolo[2,3-b]indol-3a-ol.
8 citations
TL;DR: The m-chloroperbenzoic acid oxidation of a Corynanthe-type indole alkaloid in the presence of trifluoroacetic acid produced unusual dimeric compounds, both of which had a linkage between the C-7 and C-12' positions in the indole part of the starting material.
Abstract: The m-chloroperbenzoic acid oxidation of a Corynanthe-type indole alkaloid, mitragynine (1), in the presence of trifluoroacetic acid produced unusual dimeric compounds (3 and 4), both of which had a linkage between the C-7 and C-12' positions in the indole part of the starting material
TL;DR: A new yohimbine-type indole alkaloid (1) was isolated from the stem bark of Mitragyna africanus (WILLD) collected in Nigeria, along with known seven Corynanthe-type oxindole alkaloids, two secoiridoids, three lignans, and a quinovic acid derivative as discussed by the authors.
Abstract: A new yohimbine-type indole alkaloid (1) was isolated from the stem bark of Mitragyna africanus (WILLD.) collected in Nigeria, along with known seven Corynanthe-type oxindole alkaloids, two secoiridoids, three lignans, and a quinovic acid derivative. Their structures were elucidated by spectroscopic analyses.
TL;DR: In this article, two indole alkaloids, angustilodine (1) with an unprecedented pentacyclic carbon skeleton, and Angustilocine (2), belonging to the seco-angustilobine-B group of alkaloid, were obtained from the leaf extract of the Malayan species Alstonia angustilioba, and their structures were established by spectroscopic analysis.
Abstract: Two new indole alkaloids, angustilodine (1), with an unprecedented pentacyclic carbon skeleton, and angustilocine (2), belonging to the seco-angustilobine-B group of alkaloids, were obtained from the leaf extract of the Malayan species Alstonia angustiloba, and their structures were established by spectroscopic analysis.
TL;DR: The first enantiospecific total synthesis of the indole alkaloid (+)-dehydrovoachalotine (1) has been achieved from d -(+)-tryptophan methyl ester in 28% overall yield as mentioned in this paper.
Abstract: The first enantiospecific total synthesis of the indole alkaloid (+)-dehydrovoachalotine ( 1 ) has been achieved from d -(+)-tryptophan methyl ester in 28% overall yield. The formation of the prochiral quaternary carbon center at C-16 in the key intermediate ( 12 ) was realized via a Tollens reaction from N a -methylvellosimine ( 13 ) in 95% yield. This approach could also be applied to the synthesis of many other indole alkaloids that contain a quaternary carbon center at C(16).
30 Jun 2004