Weitere furanoeremophilane aus Othonna-arten

The investigation of further Othonna species affords 23 new furanoeremophilanes and a new benzofuran-derivative. All these compounds are closely related to those isolated before from other Othonna species. Highly oxidized furanoeremophilanes seem to be typical of this genus.     

Neue furanoeremophilane und weitere inhaltsstoffe aus südafrikanischen Senecio-arten

The investigation of further 27 South African and a few other Senecio species afforded in addition to known compounds 18 new furanoeremophilanes, most of them being cacalol derivatives, two new lactones, a new eudesmane derivative and four acyl pyrrole derivatives. The structures are elucidated by spectroscopic methods mainly. The chemical results on more than 140 species now available indicate much of chemotaxonomic interest. Together with the chemical data on related genera, the taxonomic situation of the subtribe Senecioninae is discussed in connection with the proposed new classification. The chemical data are in good agreement with this new arrangement.     

Neue eremophilene aus südafrikanischen Senecio-arten

The investigation of the South African Senecio species, S. gerardii, S. scaposus, S. cathcartensis and S. rhomboideus affords several new eremophilenes, the diesters of seneremophilondiol, senescaposone and isosenescaposone, both esterified with the previously unknown 4-methyl-5-acetoxy-pent-2c-en acid, and two further esters, one esterified with cis-hex-2-enoic acid. The side chains in three of these compounds have the unusual 7α- configuration. Furthermore the germacrene derivatives rhomboidol and the corresponding acetate have been isolated. The structures are elucidated by spectroscopic methods and some chemical transformations.     

Neue C10-säureamide,furanoeremophilane und andere inhaltsstoffe aus bolivianischen Senecio-arten

The investigation of seven Bolivian Senecio species afforded in addition to known compounds five new furanoeremophilanes, two C₁₀-amides, a new isoeugenol ester and the isomer of pterophorin. The structures are elucidated mainly by spectroscopic methods. While most of the new compounds are closely related to those isolated before from Senecio species, four of them are unusual. Another is a new type of a furanoeremophilane; its biogenesis however, can be explained easily from known types.     

New furanoeremophilanes from South African Senecio species

An investigation of South African Senecio species afforded in addition to previously known compounds three new furanoeremophilanes, six compounds derived from cacalol and a dihydroeuparin derivative. Structures were elucidated by spectroscopic methods and some chemical transformations. Chemotaxonomical aspects are discussed briefly.     

Hilliardinolester und andere furanoeremophilane aus Senecio mauricei

Senecio mauricei contains seven new furanoeremophilanes, all being highly oxidized. Intensive ¹H-NMR-studies led to the configurations of these unusual compounds. The acetstes of four of them show very unusual chemical shifts of the acetate methyls. Furthermore a new eremophilane is present: 8,12-dihydroxy-7,11,9,10-tetrahydroeremophilane. The chemotaxonomic aspects are discussed briefly.     

Neue eremophilan-derivate aus Lopholaena-arten

The genus Lopholaena contains several eremophilane derivatives. The structures of four new furanoeremophilanes and one eremophilone derivative were elucidated using spectroscopic methods. The chemical relationship of Lopholaena to other genera is discussed.     

A new type of germacranolide from Vernonia species

From several South African Vernonia species, a considerable number of sesquiterpene lactones has been isolated. Together with known compounds, seven members of a new type with an enol lactone ring have been found, their structures being elucidated by spectroscopic methods and some chemical transformations. Furthermore two new derivatives of costunolide are present in two species, and three new guaianolides have been found. From some species, however, no lactones could be isolated. Together with a new bisabolene derivative, a known eremophilone has been isolated, probably for the first time, from a member of the tribe Vernonieae.     

Eremophilane derivatives from Senecio species

The investigation of two further Senecio species afforded two new furanoeremophilanes, four eremophilanolides and a new hydroxyeremophilane. The structures of two furanoeremophilane, isolated before, have been revised.     

Neue acetylenverbindungen aus chrysothamnus parryl

The investigation of Chrysothamnus parryi afforded, in addition to known compounds, several new matricaria ester derivatives. The structures were elucidated by spectroscopic methods and some chemical transformations. Furthermore, a naphthol derivative was isolated. Chemotaxonomic aspects are discussed briefly.     

Einige neue furanoeremophilane aus Senecio-Arten

The investigation of two varieties of the South African S. hypochoerideus affords, besides known compounds, six new furanoeremophilanes and a pimarene-derivative. By contrast, S. greyi has yielded two further new furanoeremophilanes and a new eremophilene. These structures are elucidated mainly by spectroscopic methods. Chemotaxonomic aspects are briefly discussed.     

New sesquiterpenes from Senecio oxyodontus

The South African plant, Senecio oxyodontus, contained in addition to known compounds several new sesquiterpenes, which were all of the bisabolene type. The structures were elucidated by spectroscopic methods and some chemical transformations. The constituents were closely related to those from one other South African Senecio species and in contrast to most Senecio species which contain very different structural types, mainly of the furanoeremophilanes type.     

Chromones and flavans from Marshallia obovata

An investigation of Marshallia obovata afforded, in addition to known thymol derivatives, one new ester. Furthermore six new chromone derivatives, all prenylated, were present together with the known spathelia chromene. The main constituent was a flavan already isolated from M. grandiflora but five new flavans were also isolated. Besides other widespread compounds a tetraester of inositol was isolated in minute amounts. All the structures were elucidated by spectroscopic methods or chemical transformations. Surprisingly, even the main 4-methoxyflavan could be split by periodic acid.     

Neue pyron-derivate aus Helichrysum-arten

The investigation of five further Helichrysum species afforded in addition to known compounds nine α-pyrone derivatives all also being phloroglucinol derivatives. Furthermore, a new toxol derivative has been isolated. The structures were elucidated by extensive NMR studies and by some chemical transformations. The chemotaxonomic situation is discussed briefly.     

Inhaltsstoffe aus Gynoxys- und Pseudogynoxys-arten

Five new furanoeremophilanes have been isolated from Gynoxys sancto antonii, while two Pseudogynoxys species yield three new polyenes. The chemotaxonomic aspects are discussed.     

Neuartige ester von eremophilen-derivaten aus südafrikanischen Senecio-arten

The investigation of three further South African Senecio species afforded, in addition to known compounds, 11 new eremophilenes and two new eud     

Chemical constituents from Neopestalotiopsis clavispora culture medium with estrogenic effects in MCF-7 cells

Estrogen is a vital hormone responsible for the development of the female reproductive system. Hence, estrogen deficiency in menopause increases various symptoms. This study aimed to discover biologically active compounds from an EtOAc-extract of Neopestalotiopsis clavispora culture medium which has previously shown estrogenic activity. A new α-pyrone (1) and a new tetramic acid derivative (2), together with hymenosetin (3) and pestalotiollide B (4), were isolated from the extract. The chemical structures of the new compounds were elucidated using MS and NMR spectroscopy, and the absolute configurations were established by quantum mechanical calculations of electronic circular dichroism and gauge-including atomic orbital NMR chemical shift, followed by DP4 + analysis. The isolated compounds were initially tested for their estrogenic activities using MCF-7 estrogen responsive human breast cancer cells. Hymenosetin (3) showed estrogenic activity by increasing the proliferation of MCF-7 cells at the concentration of 2.5 μM via the phosphorylation of estrogen receptor-α.     

Neue germacranolide aus Calea urticifolia

The investigation of Calea urticifolia afforded eight new germacranolides. While five are heliangolides, three are of a new type and have some unusual structural features. The structures are elucidated by extensive ¹H-NMR studies and some chemical transformations. In addition, a new isoeugenol and an unusual phloroglucinol derivative were isolated; the structure of the latter could only be established after some chemical transformations. Other Calea species contain typical C₁₇ acetylenes only, also present in other species of the subtribe Galinsoginae. So far, the results on Calea indicate that the genus is chemically heterogenous.     

Neue sesquiterpene aus Liabum-arten

The reinvestigation of the roots of Liabum eggersii afforded, in addition to compounds reported before, several sesquiterpene hydrocarbons with unusual carbon skeletons and the first derivative of the propellane modhephene which itself is also present. The roots of L. floribundum contain a tricyclic sesquiterpene with three five-membered rings. This ketone most probably is a derivative of the sesquiterpene silphiperfolene. The structures of the new compounds were elucidated by extensive NMR studies and by some chemical transformations. Two further species only afforded known compounds. The chemotaxonomic situation is discussed briefly.     

Eudesmane derivatives from Verbesina species

The investigation of seven Verbesina species afforded, in addition to known compounds, several new eudesmane and germacrane derivatives, all bearing a cinnamate or derivatives as residue. Furthermore, a new bisabolene aldehyde and two acetophenone derivatives were isolated. The structures were elucidated mainly by spectroscopic methods and some chemical transformations. The chemotaxonomic situation is discussed briefly.