Showing papers on "Indole alkaloid published in 2005"

Actinophyllic acid, a potent indole alkaloid inhibitor of the coupled enzyme assay carboxypeptidase U/hippuricase from the leaves of Alstonia actinophylla (Apocynaceae)

Abstract: Bioassay-guided fractionation of the aqueous extract of the leaves of Alstonia actinophylla with use of a coupled enzyme assay, CPU/hippuricase, to detect carboxypeptidase U inhibitors led to the isolation of a novel indole alkaloid, actinophyllic acid (1). The structure of 1 was determined from detailed 2D NMR studies. Actinophyllic acid was found to be a potent inhibitor of the coupled enzyme assay with an IC(50) of 0.84 microM. Actinophyllic acid possesses a unique 2,3,6,7,9,13c-hexahydro-1H-1,7,8-(methanetriyloxymethano)pyrrolo[1',2':1,2]azocino[4,3-b]indole-8(5H)-carboxylic acid skeleton.

Expression of terpenoid indole alkaloid biosynthetic pathway genes corresponds to accumulation of related alkaloids in catharanthus roseus (l.) g. don.

Abstract: Madagascar periwinkle, Catharanthus roseus (L.) G. Don, a medicinally important plant, produces anticancer dimeric alkaloids, vinblastine and vincristine, in the leaves and accumulates antihypertensive alkaloids, ajmalicine and serpentine, in the roots. This plant grows wild in distant tropical and sub-tropical geographical locations with different agro-climates and shows wide variations in morphological and alkaloid yield-related traits. In order to understand the correlation between the expression of terpenoid indole alkaloid (TIA) pathway genes and accumulation of related alkaloids, six different genetic resources of C. roseus, including the medicinal cultivars Nirmal, Prabal, Dhawal, the mutants gsr-3 and gsr-6, and one horticultural variety, Pacifica blush, were studied. The expression profiles of one early and two late TIA biosynthetic pathway genes, namely, strictosidine synthase, desacetoxyvindoline 4-hydroxylase and deacetyl vindoline 4-O-acetyl transferase were analyzed in these plants. A positive correlation between transcript abundance and accumulation of related alkaloids was observed in the different genetic resources. The potential of these TIA biosynthetic pathway genes for use in screening of high-yielding C. roseus germplasm has been discussed.

Cytokinin and ethylene control indole alkaloid production at the level of the MEP/terpenoid pathway in Catharanthus roseus suspension cells.

Abstract: The Madagascar periwinkle Catharanthus roseus accumulates a number of terpenoid indole alkaloids, some of which have high therapeutic interest. The biotechnological approach with cells in vitro remains an alternative to the field culture of periwinkle for the production of such compounds. We previously reported that two phytohormones, cytokinin and ethylene, remarkably enhanced the accumulation of alkaloids in periwinkle cell suspensions. In this work, we investigated the effects of these hormones on the regulation of several genes of the indole alkaloid biosynthetic pathway. We show that cytokinin and/or ethylene greatly enhanced the expression of the geraniol 10-hydroxylase gene. When given together, these hormones also increased the expression of three genes belonging to the methyl-erythritol pathway. These results make it possible to consider elements of cytokinin and ethylene signalling pathways as tools for improving terpenoid indole alkaloid production through metabolic engineering.

Dendridine A, a bis-indole alkaloid from a marine sponge Dictyodendrilla Species.

Abstract: A unique C2-symmetrical 4,4'-bis(7-hydroxy)indole alkaloid, dendridine A (1), was isolated from an Okinawan marine sponge Dictyodendrilla sp., and the structure was elucidated by spectroscopic data. Dendridine A (1) exhibited antibacterial and antifungal activities.

New insight into the biosynthesis and regulation of indole compounds in Arabidopsis thaliana.

Abstract: In spite of their silent and sessile life, plants are dynamic organisms that have developed advanced defence strategies in their adaptation to the pressure of herbivores and pathogens. Natural plant products play an important role as chemical weapons in this warfare. Characteristic of cruciferous plants is the synthesis of nitrogen- and sulphur-rich compounds, such as glucosinolates (Mikkelsen et al. 2002) and indole alkaloids (Pedras et al. 2000). Glucosinolates are believed to be largely non-toxic, but upon tissue disruption, they are hydrolyzed by endogenous β-thioglucosidases (myrosinases) (Rask et al. 2000) to primarily isothiocyanates and nitriles, which have many biological activities. These include not only important roles as repellents against herbivorous insects and microorganisms, but also as volatile attraction of specialized insects (Wittstock and Halkier 2002). For humans, these compounds serve as cancer-preventive agents, biopesticides, and flavor compounds (Talalay and Fahey 2001). Indole alkaloids are phytoalexins and production of specific alkaloids is usually limited to only a few species. Cruciferous plants include the model plant Arabidopsis, which produces the indole alkaloid camalexin. This review will focus on the central role of indole-3-acetaldoxime (IAOx) in the biosynthesis of indole glucosinolates, camalexin, and the phytohormone IAA.

Astonishing diversity of natural surfactants: 6. Biologically active marine and terrestrial alkaloid glycosides.

Abstract: This review article presents 209 alkaloid glycosides isolated and identified from plants, microorganisms, and marine invertebrates that demonstrate different biological activities. They are of great interest, especially for the medicinal and/or pharmaceutical industries. These biologically active glycosides have good potential for future chemical preparation of compounds useful as antioxidants, anticancer, antimicrobial, and antibacterial agents. These glycosidic compounds have been subdivided into several groups, including: acridone; aporphine; benzoxazinoid; ergot; indole; enediyne alkaloidal antibiotics; glycosidic lupine alkaloids; piperidine, pyridine, pyrrolidine, and pyrrolizidine alkaloid glycosides; glycosidic quinoline and isoquinoline alkaloids; steroidal glycoalkaloids; and miscellaneous alkaloid glycosides.

Koniamborine, the First Pyrano[3,2-b]indole Alkaloid and Other Secondary Metabolites from Boronella koniambiensis

Abstract: Two new alkaloids, (-)-cis-1,2-dihydroxy-1,2-dihydromedicosmine (3) and koniamborine (4), have been isolated from Boronella koniambiensis aerial parts. Their structures have been established from NMR and mass data. Koniamborine is a novel type of alkaloid, which derives from the pyrano[3,2-b]indole basic skeleton, described for the first time from nature. 6-Methoxy-1-methylisatin, also present in the plant material, can be considered biogenetically as a degradation product of the fused pyrone ring of 4.

Indole alkaloid and other constituents from Ocotea minarum

Abstract: From the fruits of Ocotea minarum a new indole alkaloid, tryptophol-5-O-b-D-glucopyranoside, was isolated in addition to the coumarin scopoletin and the flavonoids taxifolin, quercetin-7-O-b-D-glucopyranoside, eriodictyol-3'-O-b-D-glucopyranoside and naringenin-7-O-b-D-glucopyranoside. A new alkyl phenol, 3-(1,4-dihydroxypentyl)-5-methoxyphenol, was obtained from the heartwood in addition to 5-propylresorcinol, trans-asarone, lyonyresinol, 3-O-b-D-glucopyranosyl stigmasterol and stigmasta-4,22-dien-3-one, whereas from the trunk bark the sesquiterpene lanceolic acid (as its methyl ester derivative after methylation procedures) and b-sitosterol were isolated. 5-propylresorcinol and lanceolic acid are reported for the first time as natural products.

Actinophyllic Acid, a Potent Indole Alkaloid Inhibitor of the Coupled Enzyme Assay Carboxypeptidase U/Hippuricase from the Leaves of Alstonia actinophylla (Apocynaceae).

Abstract: Bioassay-guided fractionation of the aqueous extract of the leaves of Alstonia actinophylla with use of a coupled enzyme assay, CPU/hippuricase, to detect carboxypeptidase U inhibitors led to the isolation of a novel indole alkaloid, actinophyllic acid (1). The structure of 1 was determined from detailed 2D NMR studies. Actinophyllic acid was found to be a potent inhibitor of the coupled enzyme assay with an IC(50) of 0.84 microM. Actinophyllic acid possesses a unique 2,3,6,7,9,13c-hexahydro-1H-1,7,8-(methanetriyloxymethano)pyrrolo[1',2':1,2]azocino[4,3-b]indole-8(5H)-carboxylic acid skeleton.