Quinolizidine alkaloids as systematic markers of the Genisteae

A previously reported postulate concerning the evolution of quinolizidine alkaloids and the detailed consideration of the chemical composition led to a revised dendrogram showing proposed phylogenetic relations within the subfamily Papilionoideae in general and the tribe Genisteae in particular.     

Indole alkaloids as systematic markers of the Apocynaceae

Indole alkaloids can be characterized by skeletal specialization (S), determined upon consideration of their relative position on a biogenetic map and the number of their naturally occurring substitutional derivatives, as well as by oxidation level (O). The mean (S) and (O) for contained alkaloids of a given plant taxon are taken to represent evolutionary advancement parameters, respectively EA_s and EA_o.A correlation of these EA_s/EA_o values for tribes of the Apocynaceae-Plumerioideae reveals a chemical gradient, given by gradually increasing EA_s and EA_o values, to link Carisseae-Alstonieae-Rauvolfieae-Tabernaemontaneae.     

Quinolizidine/indolizidine alkaloids from the seed of Camoensia brevicalyx

The seeds of Camoensia brevicalyx have yielded five quinolizidine/indolizidine alkaloids. The known alkaloids camoensine and camoensidine and the n     

Benzyltetrahydroisoquinoline-derived alkaloids as systematic markers

Basic unsubstituted skeleta within biogenetic groups can be codified according to their position along biosynthetic pathways aligned in order of probability of occurrence. Correlation of the codified structural type with the taxa in which they are found is effected through frequency indices associated with the relative number of derivatives of the skeleton in the taxon and the relative number of subunits of the taxon which contain derivatives thereof. The benzyltetrahydroisoquinolines, a biogenetically related group of compounds, serves as example of the applicability of the method, which is part of an integrated system of expression of biochemical data in biological systematics.     

Iridoids as systematic markers in dicotyledon

Iridoid evolution is postulated to involve a gradual increase in the state of oxidation. From this, it appears that the iridoid-containing dicotyledons bifurcated at a primitive stage near the Ericales into the Cornales, with an extension to a Dipsacales branch and a Gentianiflorae branch, and into the Lamiiflorae.     

Polyacetylenes as systematic markers in dicotyledons

In the sequence of superorders Rutiflorae-Santaliflorae-Araliiflorae-Asteriflorae an increase in the mean oxidation state for each series of C_n-polyacetylenes and an extension in the range of the carbon atoms of these polyacetylenes in the direction of smaller numbers are observed. These trends of polyacetylene evolution also seem to be operative at lower hierarchic levels in the family Asteraceae.     

Use of the metabolic grid to explain the metabolism of quinolizidine alkaloids in Leguminosae

Evidence from feeding experiments with lysine-[2-¹⁴C] and from metabolism experiments published previously suggest the operation of a gridlike conversion of quinolizidine alkaloids in Leguminosae. Using these results and the taxonomical distribution of alkaloids a metabolic grid was devised to explain the conversion of lysine into lupin alkaloids and their interconversions.     

Chemotaxonomic significance of alkaloids in the genus Robynsiophyton

The alkaloids of the monotypic genus Robynsiophyton have been studied for the first time. Most of the quinolizidine alkaloids and esters of quinolizidine alkaloids found in the genus Pearsonia are also the major compounds in Robynsiophyton. These include lupanine, 3β-hydroxylupanine, lebeckianine, lupanine-13-angelate, cajanifoline, cryptanthine, sessilifoline and pearsonine. The results support the idea of a close affinity between Robynsiophyton, Pearsonia and Rothia. Except for the apparent absence of tigliate esters in Pearsonia, differences between the genera seem quantitative only.     

Quinolizidine alkaloids from the curare adjuvant Clathrotropis glaucophylla

The bark of Clathrotropis glaucophylla (Fabaceae) is used as admixture of curare arrow poison by the Yanomami; Amerindians in Venezuela. A new quinolizidine alkaloid (QA), (-)-13alpha-hydroxy-15alpha-(1-hydroxyethyl)-anagyrine [(-)-clathrotropine], was isolated from the alkaloid extract of C. glaucophylla bark, together with eleven known QAs: (-)-anagyrine, (-)-thermopsine, (-)-baptifoline, (-)-epibaptifoline, (-)-rhombifoline, (-)-tinctorine, (-)-cytisine, (-)-N-methylcytisine, (-)-lupanine, (-)-6alpha-hydroxylupanine and (+)-5,6-dehydrolupanine. The isolation and structure elucidation were performed with the aid of chromatographic (TLC, HPLC and CC) and spectroscopic (UV and 1D/2D NMR) methods, and mass spectrometry. To our knowledge, this is the first time quinolizidine alkaloids have been isolated from an arrow poison ingredient. It is also the first report on Clathrotropis species being used for preparation of arrow poison.     

A phytochemical study of the quinolizidine alkaloids from Genista tenera by gas chromatography-mass spectrometry

Gas chromatography coupled with mass spectrometry has been used to analyse the alkaloids present in the aerial parts of Genista tenera. Anagyrine, cytisine, N-formylcytisine, N-methylcytisine and lupanine were the major compounds, the last two alkaloids being known for their hypoglycaemic activity. Dehydrocytisine, 5,6-dehydrolupanine, rhombifoline, aphylline and thermopsine were the minor alkaloids. The characterisation of the constituents was based on comparison of their Kovats retention indexes and electron impact-mass spectrometric data recorded on-line with those of reference compounds and literature data.     

Alkaloid distribution in some species of the Papilionaceous tribes Thermopsideae and Genisteae

Alkaloid profiles of extracts of fourteen papilionaceous species in the tribes Thermopsideae and Genisteae (sensu Polhill) have been determined. Altogether, eighteen quinolizidine alkaloids, representative of four structural groups, and one dipiperidine alkaloid were identified among the legumes studied. The chemotaxonomic implications of these data are discussed.     

Molecular Phylogeny of the Papilionoideae (Family Leguminosae): RbcL Gene Sequences versus Chemical Taxonomy

Total DNA was extracted from 67 species (30 genera) of the subfamily Papilionoideae (family Leguminosae). The rbcL gene was amplified by polymerase chain reaction (PCR) and sequenced directly. RbcL sequences were evaluated with character-state (maximum parsimony; PAUP) and distance methods (neighbour-joining; MEGA). Morphology-based classifications of tribes and subtribes are mostly congruent with rbcL phylogeny. Differences occur for members of the genus Sophora and for intratribal relationships within the Genista/Cytisus complex: Sophora appears in two clades; one clade with S. japonica at the base of the Papilionoideae and a second more advanced group (with S. davidii, S. jaubertii, and S.flavescens) which represents a sister clade of the Thermopsideae. The Cytisus complex includes the genera Cytisus, Chamaecytisus, Calicotome and Spartocytisus but not Cytisophyllum which appears as a distinct member of the Genista complex. Chamaespartium sagittale is very close to Genista supporting the view that it does not represent an independent genus but should be treated as Genista sagittalis. Close to Genista are Teline and Spartium, whereas Argyrolobium, Retama, Cytisophyllum, Ulex, Petteria, Adenocarpus, Chamaespartium tridentatum and Laburnum can be considered as “outliers” of the Genista-group sensu stricto. RbcL phylogeny is compared with profiles of alkaloids and other natural products. First results indicate that secondary metabolite profiles, if compared with morphology or rbcL sequences, are of limited value as a taxonomic marker.     

Comparative biosynthesis of quinolizidine alkaloids from dl-lysine in five species of Leguminosae

Five species of the leguminosae produced radioactive lupine alkaloids after feeding with dl-lysine-[2-¹⁴C]. Saturated alkaloids and compounds with a pyridone ring were radioactive. The specific radioactivity of the isolated compounds provides evidence that conversion of lysine into the saturated alkaloids, and by further oxidation to compounds both with a pyridone ring and without a d ring.     

Isoflavonoids as systematic markers

A taxonomic procedure, applicable to biogenetic groups (BG) of secondary metabolities, involves initially the determination of the relative probability of occurrence (RPO) with respect to skeleton and substitution for each compound of the BG. The means of the RPO-values of the constituents represent the evolutionary advancement parameters (EAP) of the species. Consideration of the EAPs and of the chemical composition leads to the classification of species along chemical lines. This procedure, which is independent of morphological evidence, applied to isoflavonoids, suggests the sequence of structural changes which accompany the evolution of this BG in nature, and, used as an auxiliary criterion to the conventional morphological classification, provides the basis for understanding of the evolutionary development in the Lotoideae.     

Distribution of quinolizidine alkaloid types in nine Ormosia species (Leguminosae-Papilionoideae)

Quinolizidine alkaloids were surveyed in 22 plant samples, representing nineOrmosia species and up to five different plant parts per species, using combined gas chromatography and mass spectroscopy. The detected alkaloids were classified into 40 structural types. There was a remarkable degree of dissimilarity of alkaloid-type profiles between any two plant samples, including those obtained from the same species and even from a single tree. The similarity of alkaloid-type profiles among the studied samples varied between 0% and 79% (Jaccard similarity coefficient). Of chemotaxonomic interest was the finding of acosmine inO. isthmensis, which previously had been reported only from the related genusAcosmium. Furthermore, the alkaloid-type profile ofO. panamensis seeds was distinct from that of all other samples, supporting the hypothesis that this species is only distantly related to the other Latin AmericanOrmosia species.     

Flavonoids as taxonomic markers in old world Lupinus species

In a leaf survey of 54 specimens of 11 Old World Lupinus species three classes of flavonoids were detected: flavones (in 82%), flavonols (in 36%) and flavone C-glycosides (in 55%). The rough-seeded species were clearly distinguished from the smooth-seeded taxa by the presence of a novel 2′-hydroxyflavone, luteolin and flavone C-glycosides as major leaf constituents and by the absence of flavonols. Within the smooth-seeded species, there are three flavonoid patterns: (a) flavonols only, L. albus; (b) flavones and flavonols, L. luteus, L. hispanicus and L. angustifolius; and (c) flavones only, L. micranthus. L. angustifolius further differed in uniquely producing diosmetin as a major leaf constituent. These divisions coincide exactly with previous groupings based on alkaloidal and morphological data. Amongst the 12 samples of L. angustifolius three chemical races were distinguished and a number of diosmetin glucoside malate esters detected. The flower flavonoid aglycone patterns of the nine Old World species surveyed differed markedly from the corresponding leaf profiles by the presence of flavones: luteolin and apigenin in eight and chrysoeriol in seven species as major constituents, while flavone C-glycosides were found only in trace amount in three species. In a leaf flavonoid survey of 13 representative New World Lupinus taxa, glycoflavones were major leaf components, a variety of methylated flavones were identified and flavonols were absent. The presence of the novel 2′-hydroxyflavone in five New World species may indicate some evolutionary link with the rough seeded taxa of the Old World.     

Alkaloids of the rutaceae: their distribution and systematic significance

The biosynthesis of the alkaloids of the Rutaceae and its relevance to their systematic value is discussed. The alkaloids are divided into groups of potential systematic significance and their distribution reviewed and analysed with respect to presently accepted taxonomic classifications for the family. It is shown that, from the alkaloid data available, Engler's classification of the major sub-families Rutoideae and Toddalioideae is untenable. An hypothesis for the phylogeny of the Rutales, based on the distribution of alkaloids and other secondary metabolites, is proposed.     

The biochemical systematics of Fagaropsis angolensis and its significance in the Rutales

From the stem bark of Fagaropsis angolensis (Rutaceae) three alkaloids and two limonoids were isolated. The alkaloids were identified as the 6-acetonyl derivatives of the benzophenantridines, dihydrochelerythrine, dihydrosanguinarine and dihydronitidine, the last of these being reported for the first time. The alkaloids did not appear to be artefacts of the corresponding benzophenanthridines. The limonoids were identified as rutaevin and limonin diosphenol. The significance of these compounds in resolving the confused taxonomic position of F. angolensis is discussed. Attention is drawn to the presence of a small group of taxa within the Rutaceae capable of synthesizing 1-benzyltetrahydroisoquinoline-derived alkaloids and the potential of these taxa as a starting point for visualizing biochemical evolution within the order Rutales, and putative relationships between the Rutales and Ranales are examined.