Papers by Francesc Viladomat
In order to produce galanthamine, an alkaloid currently being tested in Alzheimer's disease thera... more In order to produce galanthamine, an alkaloid currently being tested in Alzheimer's disease therapy, we have used in vitro organ cultures of Narcissus confusus (Amaryllidaceae) plants starting from two different explants: double scale segments with basal plate from bulbs (organogenic cultures), and mature seeds (callogenic-organogenic cultures). Shoot-clumps were induced from buds obtained from twin-scales and from organogenic calluses on a MS medium supplemented with 1 mg l 1 2,4-D and 5 mg l 1 BA. Shoot-clumps were then developed partially submerged in a liquid medium. After one month of precondition, the shoot-clumps were cultured in liquid media with different concentrations of sucrose, from 3% to 18% (w/v) for 14 days. The growth of the regenerated plants treated with 9% sucrose was significantly greater. Under a photoperiod 16 h light/8 h dark, the shoot-clump cultures subjected to the two highest sucrose concentrations gave rise to higher dry weight/fresh weight ratios. Different doses of sucrose affected not only the alkaloid profile in the shoot-clump tissues but also that excreted to the medium. In all cases, shoot cultures of N. confusus were capable of galanthamine biosynthesis, with the best results at 9% sucrose concentration.
Plant Physiology and Biochemistry, 2010
Calli, shoot-clumps and regenerated plants were initiated from young fruits of Pancratium maritim... more Calli, shoot-clumps and regenerated plants were initiated from young fruits of Pancratium maritimum L. Their genetic stability was monitored by flow cytometry before chemical studies. Apolar metabolites (alkaloids extracted at pH > 7, free fatty acids and fatty alcohols, sterols etc.) were qualitatively and quantitatively analyzed by GCeMS. The results clearly demonstrated that alkaloid synthesis in P. maritimum is closely related with tissue differentiation. The highest amounts of alkaloids and presence of homolycorine and tazettine type compounds (end products of the biosynthetic pathway of the Amaryllidaceae alkaloids) were found in highly differentiated tissues. Galanthamine accumulated in the leaves of plantlets. The amount of hordenine, a protoalkaloid, is related with the ability of tissues to synthesize alkaloids. Saturated fatty acids were found in considerably higher levels in undifferentiated callus cultures and partially differentiated shoot-clumps than in regenerated plants. Mono-and dienoic fatty acids were found at higher levels in non-photosynthesizing tissues e calli, and in vitro and intact bulbs, while a-linolenic acid (trienoic acid) was found in higher amounts in the photosynthesizing leaves of shoot-clumps and regenerated plants than in bulbs and calli. Fatty alcohols were found mainly in leaves, while sterols tended to accumulate in photosynthesizing and undifferentiated tissues.
Plant Cell, Tissue and Organ Culture, 1996
Galanthamine (GAL) is increasingly used in the treatment of Alzheimer's disease. We have attempte... more Galanthamine (GAL) is increasingly used in the treatment of Alzheimer's disease. We have attempted to develop a method of producing this alkaloid using in vitro cultures of Narcissus confusus plants. The "shoot-clump" culture in liquid medium was shown to be an appropriate method for the micropropagation of this bulbous plant. The complete process included three steps: 1. culture of "twin-scales" starting from the bulbs; 2. culture of the newly formed shoots in a medium for bud proliferation (Murashige Skoog + lmg 1-1 of 2,4-dichlorophenoxyacetic acid + 5 mg 1-1 of benzyladenine), and 3. culture of "shoot-clumps" in a liquid-shake medium.
Plant Cell Reports, 1999
In vitro cultures from two strains of Narcissus confusus (Amaryllidaceae) initiated from mature s... more In vitro cultures from two strains of Narcissus confusus (Amaryllidaceae) initiated from mature seeds were screened for their ability to produce alkaloids. Protocols for callus induction, somatic embryogenesis and organogenesis were established. The alkaloid contents were determined by HPLC. Undifferentiated calli produced small amounts of galanthamine, which increased with the degree of tissue differentiation. Scanning electron micrographs of the cultures at different stages of development were made. Embryogenic friable calli were maintained in culture for more than 2 years, retaining a high regeneration capability. All regenerated plants showed normal morphological characteristics.
Phytochemistry, 2004
Sixteen more Amaryllidaceae alkaloids have been isolated from bulbs of Crinum kirkii Baker of whi... more Sixteen more Amaryllidaceae alkaloids have been isolated from bulbs of Crinum kirkii Baker of which noraugustamine and 4a,Ndedihydronoraugustamine are hitherto unknown. Their structures and those of earlier known alkaloids have been established by physical and spectroscopic analysis. Application of 2D NMR techniques was used for complete characterization of the alkaloids as well as of 3-O-acetylsanguinine. 1,2-Diacetyllycorine and 3-O-acetylsanguinine showed activity against Trypanosoma brucci rhodesiense, the parasite associated with sleeping sickness. 3-O-acetylsanguinine also showed some activity against Trypanosoma cruzi.
Phytochemistry, 1996
Twelve alkaloids have been isolated from bulbs of Brunsvigia orientalis. 1-Epibowdensine, lepidem... more Twelve alkaloids have been isolated from bulbs of Brunsvigia orientalis. 1-Epibowdensine, lepidemethoxybowdensine and 1-epidecacetylbowdensine are reported here for the first time. The structure and stereochemistry of these new alkaloids have been determined by physical and spectroscopic methods. The ~H and 13C NMR spectra of 6-hydroxycrinamine (both epimers) and crinamidine were completely assigned by means of 2D NMR techniques.
Food Chemistry, 2007
... times. Ethyl acetate phases were combined and evaporated under vacuum using a rotavapor at 40... more ... times. Ethyl acetate phases were combined and evaporated under vacuum using a rotavapor at 40 °C until dryness (extract 4) (Justesen, Knuthsen, & Leth, 1998). 2.3. Compositional analyses. 2.3.1. Total phenolics. Total phenolics ...
CHEMICAL & PHARMACEUTICAL BULLETIN, 2003
Thirteen alkaloids have been isolated from dried bulbs and leaves of flowering Eucharis amazonica... more Thirteen alkaloids have been isolated from dried bulbs and leaves of flowering Eucharis amazonica (Amaryllidaceae). The alkaloids, 7-methoxyoxoassoanine, 6-O-methylpretazettine and apohaemanthamine, are reported for the first time from a natural source.
ChemInform, 1999
ABSTRACT ChemInform is a weekly Abstracting Service, delivering concise information at a glance t... more ABSTRACT ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Analytica Chimica Acta, 2004
A simple high-performance liquid chromatography (HPLC) method for the separation and quantitative... more A simple high-performance liquid chromatography (HPLC) method for the separation and quantitative determination of the main antioxidant phenolic compounds from bitter fennel, Foeniculum vulgare, was developed. The use of a narrow bore reversed phase (RP) C18 column and an acidic mobile phase enabled ten compounds (caffeoylquinic acids, dicaffeoylquinic acids, flavonoids and rosmarinic acid) to be separated within a 40min time
ChemInform, 2002
Seven alkaloids have been isolated from fresh bulbs of Narcissus angustifolius subsp. transcarpat... more Seven alkaloids have been isolated from fresh bulbs of Narcissus angustifolius subsp. transcarpathicus (Amaryllidaceae). Nangustine, reported here for the first time, is the first 5,11-methanomorphanthridine alkaloid with a C-3/C-4 substitution. The structure and stereochemistry of this new alkaloid, as well as those previously known, have been determined by physical and spectroscopic methods. Spectroscopic data of pancracine have been completed. The in vitro assay activity against the parasitic protozoa Trypanosoma brucei rhodesiense, Trypanosoma cruzi, Leishmania donovani and Plasmodium falciparum was carried out with the compounds nangustine and pancracine. #
Seven alkaloids have been isolated from fresh bulbs of Narcissus angustifolius subsp. transcarpat... more Seven alkaloids have been isolated from fresh bulbs of Narcissus angustifolius subsp. transcarpathicus (Amaryllidaceae). Nangustine, reported here for the first time, is the first 5,11-methanomorphanthridine alkaloid with a C-3/C-4 substitution. The structure and stereochemistry of this new alkaloid, as well as those previously known, have been determined by physical and spectroscopic methods. Spectroscopic data of pancracine have been completed. The in vitro assay activity against the parasitic protozoa Trypanosoma brucei rhodesiense, Trypanosoma cruzi, Leishmania donovani and Plasmodium falciparum was carried out with the compounds nangustine and pancracine. #
The fractionation of a methanolic extract of Tagetes maxima guided for antioxidant activity resul... more The fractionation of a methanolic extract of Tagetes maxima guided for antioxidant activity resulted in the isolation of three acylated quercetagetin glycosides, quercetagetin-
Journal of chemical ecology, 2003
Merendera montana (Liliaceae) is an endemic plant broadly, but exclusively, occurring in the Iber... more Merendera montana (Liliaceae) is an endemic plant broadly, but exclusively, occurring in the Iberian Peninsula where it is one of the most abundant species in rangelands grazed by sheep and on the routes used by migrating sheep herds. In spite of showing a peculiar phenology adapted to Mediterranean regions (leaves remain green from fall to spring and are absent in summer), this species has also successfully colonized high altitude environments (up to 2300 m), and abundant populations can be found in montane and subalpine pasturcs. Chemical analysis has shown a high forage quality as well as the presence of tropolone alkaloids (similar to other species of the genus Merendera), mainly colchicine, 3-demethylcolchicine, and colchicoside. In general terms, the alkaloid content was significantly lower in the subterranean corms than in the leaves. No remarkable seasonal variations in total alkaloids was found, although an increase of colchicoside in the corms and a decrease of colchicine ...
Phytochemistry, 2002
The ethanolic extract of bulbs of Cyrtanthus obliquus (L.f.) Ait yielded the new dinitrogenous al... more The ethanolic extract of bulbs of Cyrtanthus obliquus (L.f.) Ait yielded the new dinitrogenous alkaloid obliquine (1), 3S, 4aS, 11S, 10bS-3,4,4a,13,11,5,6-heptahydro-5[2-(4-hydroxyphenyl)ethyl]-3-methoxy-13-methyl-[1,3-dioxolo[4,5-g]indolo[3,3a-c]-isoquinolin-12-one, together with the five known structures 11a-hydroxygalanthamine, 3-epimacronine, narcissidine, tazettine and trisphaeridine. All structures were established using 1D and 2D NMR techniques and HREIMS. The alkaloids were tested for cytotoxicity against two mammalian cell lines and did not show activity at concentrations up to 100 mg/ml.
Talanta, 2011
Galanthamine, an acetylcholinesterase inhibitor marketed as a hydrobromide salt for the treatment... more Galanthamine, an acetylcholinesterase inhibitor marketed as a hydrobromide salt for the treatment of Alzheimer's disease, is obtained from some Amaryllidaceae plants. A new method was developed and validated for its quantification by GC-MS in different plant sources: bulbs and leaves from Narcissus confusus; bulbs from N. pseudonarcissus cv. Carlton; and leaves and in vitro cultures from L. aestivum. Samples (50 mg) were extracted with methanol (1 mL) for 2 h, then aliquots of the extracts were silylated and analyzed by GC-MS. The calibration line was linear over a range of 15-800 g galanthamine/sample, ensuring an analysis of samples with a content of 0.03-1.54% analyte referred to dry weight. The recovery was generally more than 95%. Good inter-and intra assay precision was observed (RSD < 3%). Principal component analysis of GC-MS chromatograms allowed discrimination of the plant raw material with respect to species, organs and geographical regions. The analytical method developed in this study proved to be simple, sensitive and far more informative than the routine analytical methods (GC, HPLC, CE and NMR), so it may be useful for quality control of plant raw materials in the pharmaceutical industry.
Rapid Communications in Mass Spectrometry, 2004
Liquid chromatography coupled to negative electrospray ionization (ESI) tandem mass spectrometry ... more Liquid chromatography coupled to negative electrospray ionization (ESI) tandem mass spectrometry (MS/MS) employing a triple quadrupole mass spectrometer was used in the structural determination of acylated flavonoid-O-glycosides and methoxylated flavonoids occurring in Tagetes maxima. The compounds were identified by experiments in full scan mode (MS), and tandem mass experiments (MS/MS) of precursor ion scan, product ion scan, and neutral loss scan modes. In order to characterize the aglycones of the flavonoid glycosides, in-source fragmentation of the deprotonated molecule [M-H] À followed by product ion scan of the resulting aglycone [A-H] À were performed. This combined approach allowed the identification of 51 phenolic compounds, including flavonoid-O-glycosides acylated with galloyl, protocatechuoyl, coumaroyl or caffeoyl groups, methoxylated flavonoids, and hydroxycinnamic acid and phenolic acid derivatives, none of them previously reported in Tagetes maxima.
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Papers by Francesc Viladomat