CHLOROPLAST DNA VARIATION WITHIN AND AMONG GENERA OF THE HEUCHERA GROUP (SAXIFRAGACEAE): EVIDENCE FOR CHLOROPLAST TRANSFER AND PARAPHYLY

The Heuchera group (Saxifragaceae) comprises Bensoniella, Conimitella, Elmera, Heuchera, Lithophragma, Mitella, Tellima, Tiarella, and Totmiea. Earlier studies employing morphology, karyology, and flavonoid chemistry indicated that these genera form a natural group, but failed to resolve relationships among them. Restriction site analysis of chloroplast DNA (cpDNA) suggests that Bensoniella, Tolmiea, and Lithophragma are close allies and form the sister group of a large clade containing the remaining six genera. Mitella and Heuchera are both paraphyletic based on cpDNA data. cpDNA data, in conjunction with morphological and allozyme data, suggest at least four examples of intersectional hybridization and subsequent chloroplast capture in Heuchera. Several of these events may be explained via a stepping stone model in which the chloroplast genome of a species was captured by a second species, and then ultimately by a third taxon. Two well-differentiated groups of Tellima populations were detected: one group has a unique chloroplast genome characterized by nine autapomorphies, and the second group has a chloroplast genome identical to that found in M. trifida and M. diversifolia. cpDNA and allozyme data suggest that some Tellima populations probably obtained their chloroplast genome via intergeneric hybridization with M. trifida, M. diversifolia, or the ancestor of these taxa. The occurrence of intergeneric chloroplast transfer in some populations of Tellima, as well as extensive intersectional chloroplast capture in Heuchera, not only suggests caution in the use of cpDNA restriction site data in phylogenetic reconstruction, but also demonstrates again the importance of adequate sampling of conspecific populations. If the intergeneric relationships in the Heuchera group suggested by cpDNA analysis are accurate, fundamental questions arise regarding the validity of certain morphological traits as good taxonomic characters in Saxifragaceae. Furthermore, significant taxonomic changes at the generic level would be necessary.     

The flavonoids of ferns in the isolated genera Loxsoma and Loxsomopsis

Kaempferol and quercetin 3-O-glucosides and 3-O-rhamnoglucosides are common to both Loxsoma cunninghamii and Loxsomopsis costaricensis, but in the former the new flavonoid glycosides, kaempferol and quercetin 3-O-glucoside-7-O-arabinoside have also been identified. The data are consistent with the proposed taxonomic relationship between these geographically isolated genera. Comparative flavonoid chemistry indicates that the Loxsomaceae may be a primitive family, not closely related to the Hymenophyllaceae or the Cyatheaceae.     

Further studies of flavonols of Clibadium (compositae)

The flavonoids of an additional eight species of Clibadium have been determined. The compounds are derivatives of kaempferol, quercetin and quercetagetin. O-Methylated quercetagetin derivatives were found in several taxa with the possibility that 6-methoxykaempferol may also exist in one collection. Kaempferol and quercetin exist as 3-O-glucosides, galactosides, rhamnosides, rutinosides and diglucosides although not all glycosides occur in each taxon. Quercetagetin derivatives occur as 7-O-glucosides. Observations on these newly investigated species confirm previous work in the genus that three types of flavonoid profiles exist: (1) kaempferol and quercetin 3-glycosides; (2) kaempferol and quercetin 3-glycosides plus quercetagetin 7-glucoside; and (3) kaempferol and quercetin 3-glycosides plus quercetagetin 7-glucoside and O-methylated derivatives of quercetagetin.     

Flavonol glycosides of Euphorbia retusa and E. sanctae-catharinae

The flavonoid glycosides of Euphorbia retusa and E. sanctae-catharinae are reported. Besides a number of common flavonol glycosides, kaempferol and quercetin 3-glucuronide-7-glucosides are reported for the first time.     

A morphological and chemical study of Populus acuminata Rydberg

Evidence from morphology, flavonoid chemistry, and field observations suggests thatPopulus acuminata is of hybrid origin. The putative parents areP. angustifolia, the narrow leaf cottonwood, and deltoid leaved plants that are assigned toP. sargentii (P. deltoides var.occidentalis), P. fremontii, orP. wislizenii (P. fremontii var.wislizenii). Populus angustifolia exhibits a series of flavonol glycosides (kaempferol, quercetin, and myricetin) in its leaves. By contrast, the major leaf flavonoids of the broad leaved plants are flavone glycosides (apigenin and luteolin).Populus acuminata is intermediate between the suspected parents in morphological features. Additionally, the leaves of mostP. acuminata plants contain the exact summation of the flavonoid compounds characteristic of the putative parents. A diploid chromosome number of 2n = 38 was obtained for six plants, which confirms the one previous report for the species. Meiosis was regular in all cases. Correlated data indicate that the majority of plants ofP. acuminata represent F₁ hybrids and that complex hybridization is not common. Evidence from morphological and chemical studies is presented to show that in certain instances backcrossing to both parents has occurred. Results gathered in this study show thatP. ×andrewsii is undoubtedly “typical”P. acuminata, but the type specimen is from a sucker shoot, and thus has been interpreted as a backcross toP. sargentii. Populus acuminata var.rehderi is not considered worthy of taxonomic recognition.     

Flavonoids from Zea mays pollen

The flavonol glycosides of quercetin, isorhamnetin and kaempferol were isolated from Zea mays pollen. The most prominent flavonols were diglycosides of quercetin and isorhamnetin. Flavonol 3-O-glucosides of quercetin, isorhamnetin and kaempferol, and triglucosides of quercetin and isorhamnetin, were minor components. The flavonoid pattern of maize pollen is characterized by the accumulation of quercetin and isorhamnetin diglycosides and by the absence of flavones, which are common in other maize tissues.     

Flavonoid glycosides of Tribulus pentandrus and T. Terrestris

Twenty-five flavonoid glycosides were detected in Tribulus pentandrus and T. terrestris. The glycosides belong to the common flavonols, kaempferol, quercetin and isorhamnetin, with the 3-gentiobiosides as the major glycosides. Traces of a flavone (tricin) glycoside was also present in T. pentandrus. The separation of Tribulaceae as a distinct family from Zygophyllaceae is discussed.     

Flavonoid glycosides and the chemosystematics of Eucalyptus camaldulensisis

Leaf flavonoid glycosides of Eucalyptus camaldulensis were identified as kaempferol 3-glucoside and 3-glucuronide; quercetin 3-glucoside, 3-glucuronide, 3-rhamnoside, 3-rutinoside and 7-glucoside, apigenin 7-glucuronide and luteolin 7-glucoside and 7-glucuronide. Two chemical races were observed based on the flavonoid glycosides. These races correspond to the northern and southern populations of species growing in Australia. The Middle Eastern species examined were found to belong to the southern Australian chemical race. The major glycosides of E. occidentalis proved to be quercetin and myricetin 3-glucuronide.     

Leaf flavonoid and other phenolic glycosides as indicators of parentage in six ornamental Fuchsia species and their hybrids

In a leaf flavonoid analysis of six Fuchsia species and seven Fuchsia hybrids, flavonols were found to be abundant in all taxa except F. procumbens. Flavone glycosides were found in only three species: luteolin 7-glucoside in F. splendens; and luteolin and apigenin 7-glucuronides and 7-glucuronidesulphates, tricin 7-glucuronidesulphate and diosmetin 7-glucuronide from one or both of the New Zealand species F. procumbens and F. excorticata. Luteolin 7- glucuronidesulphate is reported for the first time. Other less common phenolics identified include the flavanone, eriodictyol 7-glucoside from F. excorticata, a galloylglucose from F. triphylla, and a galloylglucosesulphate present in all taxa. Eight of the flavonoid glycosides proved useful as marker substances for particular Fuchsia species: quercetin 3- rhamnoside, 3-glucuronide and 3-rutinoside for F.fulgens; quercetin and kaempferol 3-galactosides for F. boliviana var. luxurians; diosmetin 7-glucuronide for F. excorticata and apigenin 7-glucuronide and 7-glucuronidesulphate for F. procumbens. The chemical results on the hybrids support the view that the cultivar ‘Mary’ is a hybrid of F. boliviana var. luxurians and F. triphylla and that both F.fulgens and F. triphylla are involved as parents of the cultivars ‘Koralle’ and ‘Traudchen Bondstedt’.     

Flavonoids of someVigna-plants in leguminosae

Flavonoids in five lines ofVigna mungo, fifteen lines ofV. radiata var.radiata and two lines ofV. radiata var.sublobata, which belong to the subgenus Ceratotropis, were examined. In hypocotyls, seed-coats and mature leaves of those plants, twelve kinds of flavonoid including three anthocyanins, two leucoanthocyanins, two glycoflavones and five flavonol glycosides were found, and their distribution pattern in twenty-two lines of the legumes is discussed. The leaves ofV. radiata var.radiata and var.sublobata contained the glycosides (mainly rutin) of both quercetin and kaempferol, while those ofV. mungo contained only kaempferol glycosides, with robinin as the predominant pigment, and the purple-red hypocotyls of the former group contained delphinidin 3-p-coumaroylglucoside, while those of the latter contained cyanidin 3-glucoside, although delphinidin 3-glucoside was commonly found in all of the plants. With the exception of two lines, all of the seed-coats examined contained in common four compounds of vitexin, isovitexin, leucocyanidin and leucodelphinidin, whereas in addition to these pigments the black seed-coats ofV. mungo andV. radiata var.sublobata TC 1965 contained delphindin 3-glucoside.     

Leaf flavonoids from Croton urucurana and C. floribundus (Euphorbiaceae)

Flavonoids were isolated by PVPP column chromatography of leaf extracts of Croton floribundus Spreng and C. urucurana Baill. and identified by NMR and co-chromatography with standards. The two species revealed highly distinct flavonoid profiles. C. urucurana, belonging to the phylogenetically basal section Cyclostigma, yielded the flavone C-glycosides vitexin and orientin, quercetin and the O-glycosides quercetin 7-O-rhamnoside, rhamnitrin and rutin, in addition to tiliroside. Instead, C. floribundus, from the more derived section Lasiogyne, yielded no C-glycosides, but a high diversity of classes of flavonols, including kaempferol, three flavonol O-methyl ethers, isoquercitrin, three tri-O-galactosides, in addition to tiliroside and an isorhamnetin-coumaroyl-O-glycoside. The present work is the first report for Croton of two rhamnosides (isolated from C. urucurana). It is also the first report for Euphorbiaceae of two tri-O-glycosides obtained from C. floribundus. The distribution of flavonoids in the two species as determined by HPLC-DAD of extracts of small leaf samples of herbarium specimens is highly similar with the profiles resulting from isolation of compounds from bulky leaf samples. Differences among specimens of the same species were restricted to relative proportions of individual constituents. The results indicate that flavonoid profiles are effective to characterize and distinguish the two species. The present results, combined with literature data, supports the condition of tiliroside as a marker of Croton and the hypothesis of an evolutionary trend in the genus toward the loss of C-glycosides and a progressive complexity of flavonoid profiles.     

Purification and Identification of Flavonoids from the Yellow Green Cocoon Shell (Sasamayu) of the Silkworm,Bombyx mori

Three quercetin glycosides, quercetin 5-O-β-D-glucoside, quercetin 7-O-β-D-glucoside, and quercetin 4′-O-β-D-glucoside, and two kaempferol glycosides, kaempferol 5-O-β-D-glucoside and kaempferol 7-O-β-D-glucoside, along with their aglycones, quercetin and kaempferol, were isolated from an ethanolic extract of Sasamayu cocoon shells. The chemical structures were characterized by chemical and spectroscopic methods including UV spectrometry and HPLC-ESI-MS. The five flavonol glycosides of the shell are different structurally from those of the leaves of mulberry (Morus alba). It was suggested that potent antioxidative activity in the cocoon is mainly due to flavonoid compounds since free radical scavenging activity was found in the cocoon flavonoids identified here.     

Leaf flavonoid glycosides as chemosystematic characters in Ocimum

Thirty-one accessions of nine species belonging to three subgenera of Ocimum (basil, family Lamiaceae) were surveyed for flavonoid glycosides. Substantial infraspecific differences in flavonoid profiles of the leaves were found only in O. americanum, where var. pilosum accumulated the flavone C-glycoside, vicenin-2, which only occurred in trace amounts in var. americanum and was not detected in cv. Sacred. The major flavonoids in var. americanum and cv. Sacred, and also in all other species investigated for subgenus Ocimum, were flavonol 3-O-glucosides and 3-O-rutinosides. Many species in subgenus Ocimum also produced the more unusual compound, quercetin 3-O-(6″-O-malonyl)glucoside, and small amounts of flavone O-glycosides. The level of flavonol glycosides produced was reduced significantly in glasshouse-grown plants, but levels of flavone glycosides were unaffected. A single species investigated from subgenus Nautochilus, O. lamiifolium, had a different flavonoid glycoside profile, although the major compound was also a flavonol O-glycoside. This was identified as quercetin 3-O-xylosyl(1‴→2″)galactoside, using NMR spectroscopy. The species investigated from subgenus Gymnocimum, O. tenuiflorum (=O. sanctum), was characterised by the accumulation of flavone O-glycosides. These were isolated, and identified as the 7-O-glucuronides of luteolin and apigenin. Luteolin 5-O-glucoside was found in all nine species of Ocimum studied, and is considered to be a key character for the genus.     

The leaf flavonoids of the Zingiberales

A survey of flavonoids in the leaves of 81 species of the Zingiberales showed that, while most of the major classes of flavonoid are represented in the order, only two families, the Zingiberaceae and Marantaceae are rich in these constituents. In the Musaceae (in 9 species), Strelitziaceae (in 8 species) and Cannaceae (1 of 2 species) flavonol glycosides were detected in small amount and in the Lowiaceae no flavonoids were fully identified. In the Zingiberaceae kaempferol (in 22%), quercetin (72%) and proanthocyanidins (71%) are distributed throughout the family. The two subfamilies of the Zingiberaceae may be distinguished by the presence of myricetin (in 26%), isorhamnetin (10%) and syringetin (3%) in the Zingiberoideae and of flavone $\text{C-}\text{glycosides}$ (in 86% of taxa) in the Costoideae. A number of genera have distinctive flavonol profiles: e.g. Hedychium species have myricetin and quercetin. Roscoea species isorhamnetin and quercetin and Alpinia species kaempferol and quercetin glycosides. A new glycoside, syringetin 3-rhamnoside was identified in Hedychium stenopetalum. In the Zingiberoideae flavonols were found in glycosidic combination with glucuronic acid, rhamnose and glucose but glucuronides were not detected in the Costoideae or elsewhere in the Zingiberales. The Marantaceae is chemically the most diverse group and may be distinguished from other members of the Zingiberales by the occurrence of both flavone $\text{O-}$ and $\text{C-}\text{glycosides}$ and the absence of kaempferol and isorhamnetin glycosides. The distribution of flavonoid constituents within the Marantaceae does not closely follow the existing tribai or generic limits. Flavonols (in 50% of species). flavones (20%) and flavone $\text{C-}\text{glycosides}$ (40%) are found with similar frequency in the two tribes and in the genera Calathea and Maranta both flavone and flavonol glycosides occur. Apigenin- and luteolin-7-sulphates and luteolin-7,3′-disulphate were identified in Maranta bicolor and M. leuconeura var. kerchoveana and several flavone $\text{C-}\text{glycosides}$ sulphates in Stromanthe sanguinea. Anthocyanins were identified in those species with pigmented leaves or stems and a common pattern based on cyanidin-and delphinidin-3-rutinosides was observed throughout the group. Finally the possible relationship of the Zingiberales to the Commelinales, Liliales, Bromeliales and Fluviales is discussed.     

The systematic significance of flavonoids in Persea of the Southeastern United States

The systematic significance of flavonoid distribution in the southeastern United States taxa of Persea is discussed. The compounds thus far elucidated are glycosides based on quercetin, kaempferol, apigenin or luteolin.     

Flavonoids of Heterogaura (Onagraceae)

Heterogaura is a monotypic genus of the tribe Onagreae of the Onagraceae. It is endemic to south western Oregon and California. Four flavonol glycosides, kaempferol 3-O-rhamnoside, quercetin 3-O-glucoside, quercetin 3-O-rhamnoglucoside and myricetin 3-O-glucoside, were found to occur in methanolic leaf extracts of each of the populations sampled. The presence of only flavonols is consistent with flavonoid analyses from other genera of the Onagreae, including Clarkia, the closest relative of Heterogaura.     

Leaf flavonoids of Glycine subgenus Glycine in relation to systematics

A survey of leaf flavonoids and isoflavonoids in several taxa of the genus Glycne subgenus Glycine was undertaken to see if this would help interpret inter- and intraspecific relationships in the genus. C-Glycosylflavones based on apigenin were found in Glycine tomentelia, G. tabacina and G. falcata. Glycosides of quercetin and kaempferol were also detected in G. tabacina. In the cultivated soybean, G. max, and its wild annual relative, G. soja, only quercetin and kaempferol glycosides have been reported. Interspecific hybrids of Glycine species sometimes show additive flavonoid patterns in F₁ hybrid leaf tissue. All perennial wild species analysed including Glycine canescens and G. latifolia have the isoflavonoids genistin (genesitein 7-O-glucoside), daidzein and coumestrol in the leaves.     

Flavonoid glycosides from the leaves of Aphananthe aspera (Thunb.) Planch. (Cannabaceae) and their chemotaxonomic significance

From the leaves of Aphananthe aspera (Thunb.) Planch. (Family: Cannabaceae), six flavonol glycosides, such as quercetin 3-O-β-glucopyranoside (1), kaempferol 3-O-β-glucopyranoside (2), quercetin 3-O-rutinoside (3), kaempferol 3-O-rutinoside (4), quercetin 3-O-neohesperidoside (5) and kaempferol 3-O-neohesperidoside (6) were isolated and identified. Structure elucidation of these compounds was performed on the basis of NMR spectral data. All these compounds were isolated for the first time from the genus Aphananthe. Chemotaxonomic significance and distribution of these flavonoid derivatives among the genera of Cannabaceae are explained in detail.     

Flavonol derivatives of Ichthyothere terminalis

The flavonoids of Ichthyothere terminalis are based upon quercetin, with minor amounts of kaempferol and dihydroquercetin. All glycosides are linked at position-3. Quercetin 3-glucoside, 3-galactoside, and 3-arabinoside comprise the monoglycoside fraction. The diglycoside fraction consists of quercetin 3-rutinoside, 3-rhamnosylgalactoside and 3-digalactoside. The single triglycoside present was shown to be quereetin 3-rhamnosylgalactosylgalactoside. A major constituent of the aglycone fraction was shown to be 3-0-methylquercetin. The flavonoid profile of Ichthyothere terminalis shows marked ditterences from those of the related genera Clibadium and Desmanthodium.     

Flavonoids of Chrysosplenium tetrandrum

Chrysosplenium tetrandrum, from northern British Columbia, accumulates a variety of flavonoid glycosides. Several kaempferol and quercetin mono- and diglycosides were identified. The major flavonoid fraction consisted of O-methylated compounds having an hydroxyl or methoxyl substituent at position-6. Aglycones identified were 5,4′-dihydroxy-3,6,7-trimethoxyflavone, 5,6,7,3′,4′-pentahydroxy-3-methoxyflavone, 5,6,3′,4′-tetrahydroxy-3,7-dimethoxyflavone, 5,6,4′-trihydroxy-3,7,3′-trimethoxyflavone, 5,3′,4′-trihydroxy-3,6,7-trimethoxyflavone, and 5,4′-dihydroxy-3,6,7,3′-tetramethoxyflavone. All occurred as glucosides. The occurrence of 6-substitution and the preponderance of O-methylated flavonoids supports removal of Chrysosplenium from Engler's Saxifraginae.