Chemotaxonomic value of flavonoids in Chromolaena congesta (Asteraceae)

The phytochemical investigation on the aerial parts of Chromolaena congesta led to the isolation of nine flavonoids, known in the literature as genkwanin (1) kumatakenin (2) acacetin (3), kaempferol 3-methyl ether (4), apigenin (5), apigenin 5,7-dimethyl ether (6), apigenin 5-methyl ether (7), luteolin (8) and kaempferol (9). The chemical structures were established on the basis of spectral evidence. All the compounds were isolated from this species for the first time. The results from the present study provide further information about the flavonoids as taxonomic marker of the genus Chromolaena, and the chemotaxonomic significance of these compounds were also summarized.     

Phenolics from Tanacetum sinaicum (Fresen.) Delile ex Bremer & Humphries (Asteraceae)

The phytochemical investigation on Tanacetum sinaicum (Fresen.) Delile ex Bremer & Humphries led to the isolation of eight flavonoid aglycones (apigenin 1, acacetin 2, luteolin 3, chrysoeriol 4, cirsilineol 5, jaceidin 6, chrysosplenetin 7 and vitexicarpin; casticin 8), four flavonoid glycosides (apigenin 7-O-β-glucopyranoside 9, apigenin 7-O-β-glucuronide 10, luteolin 7-O-β-glucopyranoside 11 and luteolin 7-O-β-glucuronide 12) and three phenolics (4-hydroxy-3-methoxy benzoic acid 13, 3,4-dimethoxy benzoic acid 14 and 4-hydroxy acetophenone 15). Their structures were determined by chemical and spectroscopic analysis. Among them, compounds 1–3, 9, 11, 13 and 14 were reported for the first time from T. sinaicum. The chemotaxonomic significance of the isolated flavonoids was also summarized.     

Flavonoids from the Turkish endemic plant Rhaponticoides mykalea (Hub.-Mor.) M.V.Agab. & Greuter (Asteraceae)

The genus Rhaponticoides, recently segregated from the genus Centaurea, belongs to the family Asteraceae (tribe Cardueae). Rhaponticoides mykalea (Hub.-Mor.) M.V.Agab. & Greuter is an endemic species narrowly distributed in the Aegean part of Turkey. Owing to the existing anthropogenic impacts (such as urbanization and road construction) throughout its distribution range, the species has been the subject of several conservation studies. Phytochemical research on the aerial parts of R. mykalea led to the isolation of a new flavonoid, namely patuletin 7-O-(6″-E-sinapyl)-β-glucopyranoside, together with four known flavonoids from n-butanol extract. The structures of all isolated compounds were elucidated by spectroscopic analysis (1D and 2D NMR, HR-ESI-MS), as well as by comparison with the relevant literature data. All of the compounds have been isolated from the genus Rhaponticoides for the first time.     

Sesquiterpene lactones from glandular trichomes of Viguiera radula (Heliantheae; Asteraceae)

In addition to known compounds, the floral parts of Viguiera radula afforded two new sesquiterpene lactones. All compounds were detected in glandular trichomes, which were micromechanically collected from the anther appendages and analyzed by HPLC. Structure identification was performed by NMR and MS techniques.     

Chemotaxonomic significance of flavonoids and phenolic acids in the Hieracium rohacsense group (Hieracium sect. Alpina; Lactuceae, Compositae)

Five apomictic taxa from the Hieracium rohacsense group were studied for their phenolic constituent composition. The following substances represent dominant compounds in the leaves: chlorogenic acid, 3,5-dicaffeoylquinic acid, luteolin 7-O-β- -glucopyranoside, luteolin 4′-O-β- -glucuronopyranoside and apigenin 4′-O-β- -glucuronopyranoside. Within the group only quantitative differences were found, luteolin 7-O-glucoside being the most important chemotaxonomic marker. Each taxon has its own specific quantitative pattern, invariable within the taxon. Based on these characteristic profiles, H. rohacsense can be distinguished from a closely related and still undescribed taxon from Mt. Pip Ivan. The proportion of luteolin 7-O-glucoside to apigenin 4′-O-glucuronoside also clearly separates the individuals of two morphologically close species—H. ratezaticum and H. pseudocaesium, which corresponds to a few slight but recognisable morphological and phenological characteristics. The ontogenetic stage of leaf development and seasonal variation are also important factors, which must be taken into consideration, as the quantity of the substances changes during leaf ontogeny and with season.     

Systematic implications of sesquiterpene lactones in the subtribe melampodiinae

Within the tribe Heliantheae of the Asteraceae, the genetic boundaries of the subtribe Melampodinae have recently been drastically revised by Stuessy. The number of genera within the subtribe has been reduced and new generic groupings have been established. The present study correlates the distribution of sesquiterpene lactones found in these genera with the newly revised subtribal boundaries. The genera Acanthospermum, Melampodium, Polymnia and Sigesbeckia produce predominantly melampolide-type sequiterpene lactones. Limited chemical data support Stuessy's removal of the genera Desmanthodium, Clibadium and Ichthyothere from the subtribe Melampodiinae. The occurrence of melampolide-type sesquiterpene lactones in members of the genera Tetragonotheca (Helianthinae) and Enhydra (Ecliptinae) indicate a possible position of these genera in the Melampodiinae.     

Systematic implications of the sesquiterpene lactones in the “strumarium” morphological complex (Xanthium strumarium, Asteraceae) of Europe, Asia and Africa

In most populations of the “strumarium” morphological complex of Xanthium strumarium L. (sensu lato) in northern Europe and in India, a new compound, xanthinosin, is the only detectable sesquiterpene lactone. In populations of this morphological complex in Portugal and Egypt as well as in eastern Asia, USSR, Korea, Hong Kong and Taiwan, xanthinin and xanthatin occur as major constituents along with xanthinosin. Experimental F, hybrids between pistillate Indian plants which contained only xanthinosin and staminate plants from Hong Kong which contained a mixture of xanthinin, xanthatin and xanthinosin produced a mixture of compounds in which the percentage of xanthinin increased relative to its percentage in the Hong Kong parent. The sesquiterpenoid data suggest that the various taxa in the “strumarium” morphological complex can be divided into three groups: (a) X. strumarium (sensu stricto) and X. indicum König, containing primarily or exclusively xanthinosin; (b) X. sibiricum Patrin and X. brasilicum Vell., with xanthinin and xanthinosin predominating; and (c) X. inaequilaterum DC., with almost equal proportions of xanthinin, xanthatin and xanthinosin. Two other taxa of the complex. X. japonicum Widd. and X. abyssinicum Wallr., were not available for inclusion in the present study.     

The sesquiterpenoids and their chemotaxonomic implications in Senecio L. (Asteraceae)

Sesquiterpenoids are important characteristic compounds in Asteraceae plants. These compounds have been proposed to be potential chemotaxonomic markers, but this application has not been comprehensively investigated. In this paper, sesquiterpenoids from 149 species of the genus Senecio were investigated to assess their taxonomic utility. The presence and absence were encoded as binary taxonomic characteristics and subsequently utilised in a clustering analysis. The previously biosynthesis pathway of sesquiterpenoids was taken into account to explore the relationship among these species contained different sesquiterpenoid types. In addition, the DNA phylogeny was also considered to explore the distribution and evolution of sesquiterpenoids in genus Senecio further. As a result, seven chemical major sections within the Senecio were recognised based on the chemical character. Although with several exceptions, the biosynthesis pathway, molecular phylogeny and the geographical origin of these sesquiterpenoid were found to be related to the chemical sections, which largely confirmed the validity of our chemo-classification for genus Senecio. In conclusion, we suggest that the sesquiterpenoid character in Senecio has some value for the genus taxonomy but should be analysed carefully and critically.     

Phenolic compounds from aerial parts as chemosystematic markers in the Scorzonerinae (Asteraceae)

In continuation of our chemosystematic survey of the Lactuceae tribe of the Asteraceae family and of the Scorzonerinae subtribe in particular, we have studied the profiles of phenolic compounds of aerial parts of Geropogon glaber L., and seven representatives of each of the genera Scorzonera and Tragopogon. Employing HPLC-MS³, 56 phenolics amongst the seven phenolic acids and 49 flavonoids were characterized. All phenolic acids were assigned as caffeoyl quinic acid derivatives and 15 of the flavonoids were identified as aglyca and glycoside of apigenin, luteolin, and quercetin, whilst the remaining flavonoids were only partially characterized. Multivariate data analyses of the HPLC-DAD quantification data revealed no significant differences between the three genera Geropogon, Scorzonera, and Tragopogon. However, some clusters of chemically very similar species amongst them the group of Tragopogon minor Mill., Tragopogon orientalis L., and Tragopogon pratensis L. (also regarded as subspecies of T. pratensis by some authors) were identified. In contrast, the three taxa of Scorzonera hispanica s.l. (Scorzonera crispatula Boiss., S. hispanica L., and Scorzonera trachysperma Guss.) were chemically less similar and partially clustered with other morphologically less closely related species.     

Chemical constituents from the roots of Caragana grandiflora (M. B.) DC. and their chemotaxonomic importance

A comprehensive phytochemical research on roots of Caragana grandiflora, a native plant to Iran, resulted in isolation of ten compounds including four phenolic compounds (2, 4, 5, 8), two fatty alcohols (1, 6), one fatty acid (9), one triterpene (3), one glyceride derivatives (7) and one fatty acid methyl ester (10), from which eight compounds (1, 2, 4–6 and 8–10) were isolated from the genus Caragana and two compounds (5 and 10) from the family Fabaceae, for the first time. All compounds (1–10) were described from Caragana grandiflora for the first time. Chemical structures of the purified compounds were identified through FT-IR, NMR and MSS, and spectral data comparison with literature reported evidences.Our findings provide valuable information in reporting the rare existence of natural fatty acid methyl ester (10) in the Fabaceae family. Moreover, the chemotaxonomic significance of these compounds was discussed.     

Phylogenetic implications of corolla morphology in subfamily Barnadesioideae (Asteraceae)

The previously insignificant and small South American subtribe Barnadesiinae of tribe Mutisieae has been shown recently to be ancient within Asteraceae. Due to absence of a 22 kb diagnostic chloroplast inversion, plus other features, this subtribe has been elevated to subfamilial status as Barnadesioideae, now containing 90 species in nine genera. Recent cladistic analyses at the generic and specific levels based on morphology and DNA sequences (ITS and trnL intron) have revealed different relationships among taxa of the subfamily. To better understand these conflicts, we analyze specific morphological features of corollas (shape and vascularization) to develop trends (trees) in these features based on minimal structural change (i.e., morphological parsimony), and to compare these with relationships among genera derived from the two recent cladistic analyses. We define six principal types of corollas in Barnadesioideae (tubular, split, double split, ligulate, subbilabiate and bilabiate) and six principal types of corolla vascularization patterns (combinations of presence or absence of central bundles, fusion of adjacent bundles and fusion of bundles at the apex of corolla lobes). In all features we assume character states in Calyceraceae to be ancestral. In corolla shape, from tubular ancestry, we hypothesize two general evolutionary trends within the subfamily: (1) splitting of the tube, and (2) flattening of the tube. In vascularization of corollas, from an ancestral condition of one central and one lateral bundle in each corolla lobe and all traces fused at the apex, we hypothesize four basic trends: (1) gain or (2) loss of lateral vascular traces in each lobe, (3) loss of the central vein, and (4) loss of fusion of traces in lobe apices. These morphological trends allow tests of the two previous phylogenetic hypotheses by (1) counting step changes (following steps in the morphological network) in the two characters on the two competing phylogenetic trees and (2) constructing an index of morphological advancement for each genus (based on morphological trees of the two characters) and correlating these with cladistic distances within the two phylogenies. Results of both tests reveal the molecular phylogeny to be more compatible with evolutionary inferences from the two morphological features. With Fulcaldea excluded, a highly significant correlation is seen between morphological advancement and cladistic distance in the molecular phylogeny.     

入侵植物飞机草与4种牧草的竞争效应

【背景】飞机草是我国危害最严重的入侵植物之一,目前仍缺乏可持续的控制手段。【方法】运用De Wit取代试验研究法,设置2株·盆-1(42.42株·m~(-2))、4株·盆-1(84.84株·m-2)和8株·盆~(-1)(169.68株·m~(-2))3种密度,分别研究杂交狼尾草、木豆、山毛豆和宽叶雀稗与飞机草的竞争效应,以明确4种牧草对飞机草的替代控制潜力。【结果】3种密度下,杂交狼尾草和木豆均可以显著抑制飞机草的生长,其竞争平衡指数显著大于0,说明杂交狼尾草和木豆的竞争力均大于飞机草;山毛豆和宽叶雀稗的相对产量均显著小于1,其竞争平衡指数均显著小于0,说明山毛豆和宽叶雀稗的竞争力小于飞机草。【结论】杂交狼尾草和木豆可用作飞机草的替代控制植物。     

Phytoconstituents from the leaves of Dracaena cochinchinensis (Lour.) S. C. Chen

Five flavonoids, four feruloyl amide derivatives, pinoresinol, lanost-9-en-3β-ol and three steroids from the leaves of Dracaena cochinchinensis (Lour.) S. C. Chen. Of these, compound 4 was identified as a new homoisoflavanone. This publication is the first reported purification of compounds 3, 4, 6–12 from D. cochinchinensis. We also indicate the chemotaxonomic importance of these metabolites.     

Guaianolide-type sesquiterpene lactones of Montanoa tomentosa subsp. xanthiifolia and M. tomentosa subsp. rosei and the molecular structures of two pumilin analogs

Montanoa tomentosa subsp. xanthiifolia and M. tomentosa subsp. rosei produce guaianolides which are very similar to those previously reported from Berlandiera pumila, B. texana and B. lyatra. The molecular structures of 3α-epoxypumilin and 8-acetyl-9-desacylpumilin-9-methacrylate were determined by single crystal X-ray diffraction.     

Chemical constituents of Medinilla septentrionalis (W. W. Sm.) H. L. Li (Melastomataceae)

Our phytochemical investigation of the whole plants of Medinilla septentrionalis (W. W. Sm.) H. L. Li led to the isolation of five tannins (1–5), five phenolic acids and phenolic acid derivatives (6–10), four flavonoids (11–14), two triterpenes (15 and 16), and one hydantoin derivative (17). The structures of the obtained compounds were identified using spectrometric methods (¹H NMR, ¹³C NMR and MS). This is the first study reporting on the chemical constituent of M. septentrionalis and the chemotaxonomic relationships between Medinilla and other genera of Melastomataceae.