E. T. Elema

DISTRIBUTION OF ALKALOIDS AND TANNINS IN THE CRASSULACEAE

Abstract Alkaloid and tannin levels of 36 species of the Crassulaceae were compared. The taxa investigated were Crassula multicava , Echeveria venezuelensis , Pachyphytum compactum , Kalanchoe (two spp.), Bryophyllum daigremontianum , Sedum (23 spp.), Aeonium (four spp.) and Sempervivum (three spp.). Apart from the alkaloidal species of Sedum , only E. venezuelensis was found to contain piperidine alkaloids, i.e. pelletierine and N -methyl pelletierine. Proanthocyanidins (condensed tannins) and galloyl esters were found in all genera, but they were absent from six out of 11 Sedum species containing piperidine alkaloids. The results indicate a dichotomy between the distribution of alkaloids and tannins, which is in good agreement with the major evolutionary trends within the family as inferred from chloroplast DNA restriction site variation. The distribution of alkaloids appears to be limited to the “ Acre ” lineage, which comprises the Asian, Eurasian and American Sedum species with a reticulate testa as well as the Central American Sedoideae and Echeverioideae. The parallel occurrence of alkaloids and a complex of apparently primitive flower and seed characters in the terminal “ Acre ” clade indicate the derived rather than the primitive condition of the latter features. The most parsimonious explanation for this marked inconsistency is a reversal of the floral structure at the basis of the “ Acre ” lineage, mimicking the floral structure of ancestral angiosperms.

Fluorodensitometric determination of potato glycoalkaloids on thin-layer chromatograms

Abstract Separation and analysis of solanine and chaconine has been achieved by thin- layer chromatography using an optical brightener as detection reagent. The conditions for optimal measurement in situ have been established. The method has been applied to the examination of leaf and tuber extracts of Solanum tuberosun cultivars. The errors in sample preparation and quantitative analysis range from 2.5 to 5.5%.

PYRROLIZIDINE ALKALOIDS, FLAVONOIDS AND VOLATILE COMPOUNDS IN THE GENUS EUPATORIUM - EUPATORIUM-CANNABINUM L, AN ANCIENT DRUG WITH NEW PERSPECTIVES

Within the scope of a study of antitumour compounds in higher plants a survey is given concerning the presence of pyrrolizidine alkaloids, flavonoids and volatile compounds inEupatorium species. Preliminary results of a phytochemical study of these compounds inE. cannabinum are also presented.From the results of a GC-MS analysis of an alkaloid extract from aerial parts ofE. cannabinum the conclusion can be drawn, that the composition of pyrrolizidine alkaloids is more complicated than reported in literature. This is caused by the fact that different stereoisomers exist. The presence of at least two alkaloids with a molecular weight of 283 (supinine or isomers) and four alkaloids with a molecular weight of 299 (echinatine or isomers) could be shown. In subterranean plant material also other pyrrolizidine alkaloids are present. A great number of flavonoids, also as glycosides, have been shown inEupatorium species, often in low quantities. Rutin, present in manyEupatorium species, could not be detected in subterranean parts ofE. cannabinum.Relatively little attention has been paid to the analysis of volatile compounds (essential oils) ofEupatorium species. Thymol derivatives are often reported to be present inEupatorium species. Thirty-five compounds could be detected by means of a GC-MS analysis in the essential oil ofE. cannabinum about which no literature data were available.

Flavones and flavonol glycosides from Eupatorium cannabinum L.

The 6-methoxyflavones hispidulin and eupafolin have been identified for the first time from the aerial parts ofEupatorium cannabinum L. The presence of the previously known flavonol glycosides astragalin, kaempferol-3-rutinoside, hyperoside, isoquercitrin and rutin could be confirmed. Hispidulin, eupafolin and rutin were screened for cytotoxicityin vitro.

Biosystematic, molecular and phytochemical evidence for the multiple origin of sympetaly in Eurasian Sedoideae (Crassulaceae)

Abstract Traditionally the sympetalous, Eurasian Crassulaceae are classified in four genera, but combined biosystematic, molecular and chemotaxonomic studies indicate that sympetaly evolved at least eight times independently in European Crassulaceae. Morphologically Umbilicus is very distinct and at the molecular level it also represents a distinct evolutionary lineage. The other three sympetalous genera evolved from the large paraphyletic genus Sedum . Of these three taxa Pistorinia represents a monophyletic lineage, whereas Mucizonia and Rosularia , are polyphyletic. The results of the hybridization experiments and molecular analyses justify the transfer of the Mucizonia species to the polypetalous Sedum series Dasyphylla and S . series Pedicellata, respectively. Cytological, phytochemical and molecular evidence indicate that Rosularia sect. Rosularia and R . sect. Chrysantha represent independent evolutionary lineages. Moreover, cpDNA restriction site analysis indicates a close relationship between R . sect. Chrysantha and the comparium comprising Prometheum pilosum, P. sempervivoides and P. tymphaeum which were formerly included in Sedum . Consequently R . sect. Chrysantha was transferred to Prometheum . Phytochemically, however, this genus is rather diverse. In addition to these six taxa, sympetaly evolved independently in Sedum lagascae, which is closely related to polypetalous S. villosum, and in S . series Alsinefolia, which in our molecular analyses appears to be related to polypetalous S. hispanicum .

Isolation of Two Cytotoxic Diterpenes from the Fern Pteris multifida

From aerial parts of the fern Pteris multifida Poir. (Polypodiaceae) two diterpenes, entkaurane- 2β,16α-diol and ent-kaur-16-ene-2β,15α-diol, were isolated by repeated column chromatography using silica gel and silica gel impregnated with silver nitrate. The structures were confirmed by spectroscopic methods. Both compounds showed a moderate cytotoxicity to Ehrlich ascites tumour cells

A NEW QUATERNARY MOBILE PHASE SYSTEM FOR OPTIMIZATION OF TLC SEPARATIONS OF ALKALOIDS USING MIXTURE DESIGNS AND RESPONSE-SURFACE MODELING

A new combination of four organic solvents is proposed for the optimization of TLC separations of basic drugs and alkaloids. The solvents are diethylamine (DEA), methanol (MeOH), chloroform (CHCl3) and ethylacetate (EtAc). They were selected from a collection of ten solvents used in Normal Phase TLC mobile phases recommended for the separation of alkaloids and basic drugs in the literature. The selection was based on the classification of solvents according to selectivity and solubility parameters. Excluded were apolar and weak solvents that show no selective (polar) properties and are used only for the adjustment of the solvent strength. Polar solvents from different selectivity groups were selected to combine as many as possible selective effects in one solvent system. The final choice was made considering the displacement theory for Liquid Solid Chromatography. The four solvents have been intended for application in an optimization procedure that uses mixture designs and response surface modelling. The factor space is a tetrahedron of which only in a part suitable experiments can be performed, i.e. the design space. Experimentation in the design space should allow the simultaneous optimization of solvent strength and solvent selectivity. The quality of TL chromatograms was characterized by two criteria: the separation of the worst separated pair of spots (R(s)min) and the R(f) value of the slowest moving spot (kmax). In this way it is possible to influence not only the separation of the spots but also their place on the TL plate. The new four solvent system has been tested successfully in the separation of the parent alkaloids of four dry plant materials: Ipecacuanha root, Cinchona bark, Belladonna leaf and Opium. The predicted mobile phases gave better or equally good separations than the mobile phases prescribed by the European or Netherlands Pharmacopoeia for these separations. Moreover a substantial reduction of the number of solvents necessary for the composition of the mobile phase was achieved as the official procedures need eight different solvents.

GAMMA-IRRADIATION OF SENNAE FOLIUM - MICROBIOLOGICAL AND PHYTOCHEMICAL STUDIES

The effect of different doses of gamma irradiation on senna leaves was studied. No changes in sennoside content and composition were observed after irradiation with 25 kGy. It was demonstrated that a minimum dose of 10 kGy was necessary to obtain a product of good microbiological quality. Cold maceration of senna leaves has to be discouraged, because of unavoidable microbial growth. Hot extraction is the method of choice for tea preparation. The rationale of gamma irradiation is discussed.

Alkaloids in ergot found on different Gramineae in The Netherlands

AbstractThe alkaloid content and the composition of the alkaloid complex of thirteen samples of ergot sclerotia from different gramineous host species collected in The Netherlands were investigated. Two samples collected in France were also examined. Ergot ofGlyceria fluitans (L.) R.Br. did not contain alkaloids. The total alkaloid content of ergot found on the other wild grasses was more than 0.2%. The ratio between the contents of water soluble and water insoluble alkaloids of the investigated ergot sclerotia varies between 1∶10 and 1∶20. The composition of the alkaloid complex in the sclerotia was studied by quantitative thin-layer chromatography. The sclerotia could be grouped into three main categories:sclerotia ofLolium perenne L.,Festuca arundinacea Schreb. andArrhenatherum elatius (L.) P.B. ex J. et C. Presl, containing predominantly ergocornine, α- and β-ergokryptine and ergosine;sclerotia ofDactylis glomerata L.,Phalaris arundinacea L.,Alopecurus geniculatus L. andHolcus mollis L., containing predominantly ergosine, ergocristine and ergotamine;sclerotia ofMolinia caerulea (L.) Moench, containing predominantly ergocristine, ergosine and ergqmetrine. A great similarity was found between the composition of the alkaloid complex in ergot ofLolium perenne L. from different locations and also in ergot ofMolinia caerulea (L.) Moench from different locations. This similarity was less in ergot ofDactylis glomerata L. collected from different locations.