Foliar flavonoids of selected Vitis taxa in the Southeastern United States

A total of 19 compounds were isolated from the leaves of five North American members of the genus Vitis The flavonoid data indicate three distinct chemical groups: one producing flavonols, flavones and C-glycosylflavones (V. aestivalis and V. cinerea var. cinerea, one producing fiavonols and flavones (V. cinerea ver. floridana) and one producing only fiavonols ( V. vulpina and V. riparia). The fiavonoid complements of the taxa are extremely useful in taxon delimitation and in suggesting systematic relationships.     

Chemical characterisation of wild populations of Thymus from different climatic regions in southeast Spain

Thymus is taxonomically a very complex genus with a high frequency of hybridisation and introgression among sympatric species. The variation in accumulation of leaf-surface flavonoids was investigated in 71 wild populations of Thymus from different putative hybrid swarm areas in Andalucia, Spain. Twenty-two flavones, five flavanones, two dihydroflavonols, a flavonol and two unknowns were detected by HPLC–DAD combined with LC–APCI-MS analysis. The majority of compounds were flavones with a luteolin-type substitution of the B-ring, in contrast to previous reports on Macedonian taxa, which predominantly accumulate flavones with apigenin-type substitution of the B-ring. Anatomical and morphometric studies, supported by cluster analysis, identified pure Thymus hyemalis and Thymus baeticus populations, and a large number of putative hybrids. Flavonoid variation was closely related to morphological variation in all populations and is suspected to be a result of genetic polymorphism. Principal component analysis identified the presence of species-specific and geographically linked chemotypes and putative hybrids with mixed morphological and chemical characteristics. Qualitative and quantitative flavonoid accumulation appears to be genetically regulated, while external factors play a secondary role. Flavonoid profiles can thus provide diagnostic markers for the taxonomy of Thymus and are also useful in detecting hybridising taxa.     

Systematic studies in sedum section ternata (Crassulaceae)

An investigation of flavonoid compounds, pollen grains, and seed coats of the four taxa of the genusSedum sectionTernata, S. nevii, S. glaucophyllum, S. pulchellum, andS. ternatum, was undertaken to resolve the taxonomic status ofS. glaucophyllum. Flavonoid compounds were tentatively identified utilizing UV spectroscopy and shift reagents. Both flavones and fla vonols, as apigenin, luteolin, quercetin, and kaempferol aglycones and glycosides, were detected. Pollen grains and seed coats were viewed and photographed with the aid of a scanning electron microscope. Pollen grains of all four taxa were uniformly tricolporate; interspecific variation was negligible. Seed coats of all four taxa differed significantly with respect to ornamentation. Phytochemical and morphological data both support the recognition ofS. glaucophyllum as a species distinct from S.nevii.     

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.     

Flavones and anthocyanins from the leaves and flowers of Japanese Ajuga species (Lamiaceae)

Flavones and anthocyanins were isolated from the leaves and flowers of 14 Ajuga taxa (Lamiaceae), which are all native or naturalized in Japan. Of 13 flavones obtained from the leaves, 11 were characterized as apigenin, luteolin, 6-hydroxyluteolin and acacetin glycosides. Ten flavones were isolated from the flowers. Ten anthocyanins were isolated from the flowers. Six of these anthocyanins were identified as acylated delphinidin glycosides and four were shown to be acylated cyanidin glycosides. Japanese Ajuga taxa were chemotaxonomically discussed by their distribution patterns, especially foliar flavonoids.     

Flavonoid systematics of the genus Perideridia (Umbelliferae)

A survey of flavonoids in sixteen of the seventeen taxa in the genusPerideridia (Umbelliferae) showed the presence of thirteen glycosides of the flavonols kaempferol, quercetin, and isorhamnetin, and seven glycosides of the flavones apigenin, luteolin and chrysoeriol. An anthocyanin and four other flavonoids also occur, but remain unidentified dueto their low concentration. Several species characteristically produce speciesspecific compounds. The majority of species, however, produce flavonoids common to one or more taxa, but each taxon can be distinguished by its own specific complement of these flavonoids. Based on classes of flavonoids the genus can be divided into three groups: (1) those species which produce only flavonols; (2) those which produce mainly flavonols and a few flavones; and (3) those which produce predominantly flavones with flavonols absent or present only in trace amounts. Geographically, the flavonol-producing species are centered in California, extending northeastward to Idaho and eastward into Arizona. The flavonol/flavone producers are concentrated more towards the Pacific Northwest and eastward through the Rocky Mountains to the midwestern United States.     

Apport de la biochimie flavonique à la systematique du genre Lycopodium

A systematic study of Lycopodium s.l. shows that only flavones occur in the four genera Huperzia, Lepidotis, Lycopodium s.s. and Diphasium. The arrangement of these taxa is discussed on the basis of the distribution of tricin, selgin, chrysoeriol, luteolin and apigenin. The evolutionary significance of these results and the uniqueness of Lycopodium phenolic metabolism are outlined.     

Flavonoid glycosides from illuminated cell suspension cultures of Petroselinum hortense

Twenty-four different flavonoid glycosides were isolated from illuminated cell suspension cultures of parsley (Petroselinum hortense). The chemical structures of fourteen of these compounds were further characterized. The aglycones identified were the flavones apigenin, luteolin and chrysoeriol, and the flavonols quercetin and isorhamnetin. The flavones occurred either as 7-O-glucosides or as 7-O-apioglucosides, while the flavonols were 3-O-monoglucosides or 3,7-O-diglucosides. One-half of these glycosides were electrophoretically mobile and substituted with malonate residues.     

Chemosystematic aspects of flavonoid distribution in twenty-two taxa of Helenium

Distributional data for 12 flavonoids in twenty-two taxa of Helenium are presented. Flavonoids identified to date are all flavones based on luteolin and apigenin. Chemosystematic interpretations are made concerning several species and species groups.     

Flavonoid distribution of Mulinum (Apiaceae, Hydrocotyloideae, Mulineae)

Flavonoid chemistry of the genusMulinum and selected Mulineae taxa was studied. Both flavones and flavonols were identified as C- and O-glycosides. AllMulinum species contain 6,8-di-C-glycosyl chrysoeriol (flavone) and, with the exception of one, quercetin (flavonol). The presence of both flavones and flavonols in this genus weakens previous generalizations that the mulineae contain only flavonols and are primitive compared to other Apiaceae tribes. Based on the selected taxa studied,Azorella appears to differ from bothMulinum andGymnophyton in producing more kinds of flavonols, andGymnophyton appears similar toMulinum in the production of both chrysoeriol and quercetin as well as relatively few compounds. The flavonoid profile ofAsteriscium glaucum is reported as well. In general, a more homogeneous flavonoid compound composition for the Apiaceae is suggested.     

Leaf flavonoids of eupomatiaceae

The leaf flavonoids of Eupomatia bennettii and E. laurina were examined and five flavonoid compounds were detected. The most distinctive of these compounds were two methylated flavones: 7-O-methylapigenin and 7,3′-di-O-methylluteolin (velutin). The flavonoids of Eupomatiaceae are most similar to those of the Winteraceae and this similarity may be indicative of a phylogenetic relationship between the two families.     

External and internal flavonoids from Madagascarian Uncarina species (Pedaliaceae)

External and internal flavonoids were isolated from 12 Uncarina taxa (Pedaliaceae), endemic to Madagascar. Four flavone aglycones, tricetin 7,3′,5′-trimethyl ether, tricetin 7,4′,5′-trimethyl ether, 5,3′-dihydroxy-6,7,4′,5′-tetramethoxyflavone and eupatorin were isolated from leaf wax of seven Uncarina taxa, Uncarina grandidieri, Uncarina decaryi, Uncarina abbreviata, Uncarina turicana, Uncarina platycarpa, Uncarina leandrii var. leandrii and Uncarina peltata, but not Uncarina stellulifera, Uncarina perrieri, Uncarina sakalava, Uncarina leptocarpa and U. leandrii var. rechbergeri. Furthermore, eight flavonoid glycosides were isolated from the leaves. Major glycosides were apigenin and luteolin 7-O-glucuronides and occurred in all the Uncarina taxa examined, except the absence of the former compound in U. peltata. Other glycosides were identified as hispidulin, jaceosidin, chrysoeriol and tricin 7-O-glucuronides, and luteolin 7,4′-di-O-glucuronide and a flavonol, isorhamnetin 3-O-diglucoside. From the results described above, methylated flavone aglycones and glucuronides were chemical characters of the leaves of Uncarina species, and also may be those of the family Pedaliaceae. Besides, an anthocyanin, two flavonols and three flavones were isolated from the flowers of U. grandidieri, and identified as cyanidin 3-O-rutinoside (anthocyanin), quercetin and isorhamnetin 7-O-glucuronides (flavonols) and apigenin, luteolin and jaceosidin 7-O-glucuronides (flavones).     

Exudate flavones and flavanones in Origanum species and their interspecific variation

Surface flavonoids in nine species of Origanum, representing taxa from all three of the currently recognised subgeneric groups, were examined both by HPLC coupled to diode-array detection and APCI–MS. Many of the flavonoids present were characterised by O-substituent at C-6 (OH, OMe) and/or C-8 (OMe). In total, 25 flavones and flavanones are described in this study, of which 13 are new to the genus and 5,4′-dihydroxy-6,7,3′-trimethoxyflavanone is reported for the first time. Taxa in subgeneric Group A accumulated flavonoids with methoxyl groups at both C-6 and C-4′; however, taxa in subgeneric Group B did not accumulate 4′-methoxylated compounds, and taxa in Group C did not accumulate 6-methoxylated compounds.     

Distribution of exudate flavonoids in the genus Plectranthus

Thirty-four species of the genus Plectranthus (including species of the former genera Coleus and Solenostemon, fam. Lamiaceae) were surveyed for exudate flavonoids to see whether the distribution of these compounds would support a recent classification of the genus based on molecular and morphological characters. In this classification two major groups had been identified, the Coleus and Plectranthus clades. Only about 40% of the species, predominantly from the Plectranthus clade, were found to produce exudate flavonoids, which were mainly flavones. Flavanones were restricted to five species of the Plectranthus clade, whereas flavonols were only found in two species of the Coleus clade, Plectranthus montanus Benth. (synonyms Plectranthus marrubioides Hochst. ex Benth. and Plectranthus cylindraceus Hochst. ex Benth.) and Plectranthus pseudomarrubioides R.H.Willemse. Four of these flavonols were isolated from P. montanus and identified by NMR spectroscopy as the 3,7-dimethyl ether and 3,7,4′-trimethyl ether of quercetin and the 3,6,7-trimethyl ether and 3,6,7,4′-tetramethyl ether of quercetagetin. The remaining flavonols and flavones were identified by HPLC–UV and LC–MS of crude extracts on the basis of their UV and mass spectra, retention times and comparison with standards. Most flavonols were 3-methyl ethers and many of the flavones and flavonols were oxygenated at the 6-position. The most common flavones, occurring in both clades, were cirsimaritin and salvigenin, which are methoxylated at the 6- and 7-positions. 6-Hydroxylated flavones such as scutellarein and ladanein were restricted to species of the Plectranthus clade.     

Antiviral flavones from the leaves of Nicotiana tabacum

Three new flavones, tabaflavones A–C (1–3), together with three known flavones (4–6), were isolated from the leaves of Nicotiana tabacum. Their structures were elucidated by spectroscopic methods, including extensive 1D and 2D NMR techniques. Compounds 1–6 were evaluated for their anti-tobacco mosaic virus (anti-TMV) activities. The results showed compound 1 exhibited moderate anti-TMV activity with inhibition rate of 29.2%, which is close to that of the positive control. The other compounds also showed the anti-TMV activities with inhibition rates in the range of 14.2–20.8%.     

Comparison of secondary compounds in Heterozostera tasmanica from Australia and Chile

Leaves of Heterozostera tasmanica (Martens ex Aschers.) den Hartog from both Australia and Chile lack the sulfated flavones that are characteristics of Zostera. Similar phenolic compounds are present in leaves of both Australian and Chilean plants of Heterozostera, but none of the numerous flavonoids (sulfated or non-sulfated) that occur in Zostera were detected in two-directional chromatograms of the Heterozostera leaves. The nearly identical patterns of secondary compounds in leaves from Australia and Chile support their position in the same species.     

Flavonoids of Sullivantia: Taxonomic implications at the generic level within the saxifraginae

Sullivantia species were found to produce quercetin 3-O-glycosides, several of which contain glucuronic acid, as well as pedalitin (6-hydroxy-7-O-methyl luteolin), pedalitin 6-O-glycosides, and small amounts of luteolin. Sullivantia has a unique combination of compounds that distinguishes it from other genera in the Saxifraginae for which flavonoid data are available. The nature of the flavonoid compounds is in accordance with a general trend within the Saxifragaceae of reduction and replacement of flavonols by flavones.     

Chemical constituents from Lomatogonium carinthiacum (Gentianaceae)

Lomatogonium carinthiacum (Wulfen) Rchb. (Gentianaceae) is an annual plant which used in the Mongolian system of medicine against liver and bile diseases. In the present study, three flavones (1–3), four xanthones (4–7), and two iridoids (8, 9) were isolated and identified. Among them, compounds 3–5, 7, 8 were firstly isolated from the species L. carinthiucum, compounds 3-5 were isolated from the genus Lomatogonium for the first time. The Chemotaxonomic significance of these compounds was discussed in the article.     

Leaflet secretory structures of five taxa of the genus Zornia J.F. Gmel. (Leguminosae, Papilionoideae, Dalbergieae) and their systematic significance

A survey of the secretory structures of leaflets has been carried out for five taxa of the genus Zornia J.F. Gmel. to assess possible taxonomic value of the glands, taking into account that these taxa, Zornia curvata Mohlenbr., Z. gemella Willd. ex Vogel, Z. glabra Desv., Z. latifolia Sm. and Z. reticulata Sm., have overlapping diagnostic characters. The leaflet secretory structures of the five studied taxa of Zornia were mucilage epidermis, mucilage cavities, and idioblasts secreting phenolic compounds. Mucilage epidermis is found in all five aforementioned taxa. Mucilage cavities are observed on both epidermal surfaces of the leaflets in four taxa, the exception being Z. glabra, whose cavities occur only on the abaxial surface. Idioblasts secreting phenolic compounds were detected only in the mesophyll of Z. latifolia and Z. reticulata. The joint occurrence of mucilage epidermis with mucilage cavities seems to be of unifying value for the five taxa analyzed. The position of mucilage cavities and the occurrence of secretory idioblasts in the mesophyll of the leaflets are of diagnostic value, providing a key to enable identification of the taxa studied. This study reveals that the secretory structures provide important information in support of systematic studies of the Leguminosae. In relation to the five taxa of Zornia studied, current results suggest recognition of four species: Z. curvata, Z. glabra, Z. latifolia, and Z. reticulata.     

Flavonoids from the leaf resin of Adenostoma sparsifolium

Four flavonoids were identified from the external leaf extract of Adenostoma sparsifolium: the two new flavones 3, 7-dihydroxy-5, 6-dimethoxyflavone and 3, 5, 7-trihydroxy-8-methoxyflavone and the known compounds galangin and pinocembrin.