Neue prenylflavanone aus Helichrysum hypocephalum

From the aerial parts of H. hypocephalum several new prenylated flavones were isolated, their structures being elucidated by spectroscopic methods and by some chemical transformations. In addition, a new lactone derived from oleic acid is present.     

Zwei neue sesquiterpenlactone und eine neue sesquiterpensäure aus Helenium puberulum

The reinvestigation of Helenium puberulum afforded in addition to known compounds two new sesquiterpene lactones, desacetyl-isobigelovin and a guaianolide, and an anomalic sesquiterpene hydroxy acid. The structures are elucidated by spectroscopic methods. Chemotaxonomic aspects are discussed briefly.     

Flavonoids of Helichrysum chasmolycicum and its antioxidant and antimicrobial activities

From the aerial parts of Helichrysum chasmolycicum P.H Davis, which is an endemic species in Turkey, the flavonoids apigenin, luteolin, kaempferol, 3,5-dihydroxy-6,7,8-trimethoxyflavone, 3,5-dihydroxy-6,7,8,4′-tetramethoxyflavone, apigenin 7-O-glucoside, apigenin 4′-O-glucoside, luteolin 4′-O-glucoside, luteolin 4′,7-O-diglucoside, kaempferol 3-O-glucoside, kaempferol 7-O-glucoside and quercetin 3-O-glucoside were isolated. The methanol extract of the aerial parts of H. chasmolycicum showed antioxidant activity by DPPH method (IC₅₀ 0.92 mg/mL). Antimicrobial activity test was performed on the B, D, E extracts and also 3,5-dihydroxy-6,7,8-trimethoxyflavone and kaempferol 3-O-glucoside which were the major flavonoid compounds obtained from aerial parts of H. chasmolycicum by microbroth dilutions technique. The E (ethanol-ethyl acetate) extract showed moderate antimicrobial activity against Pseudomonas aeruginosa, B (petroleum ether-60% ethanol-chloroform) extract and 3,5-dihydroxy-6,7,8-trimethoxyflavone showed moderate antifungal activity against Candida albicans.     

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.     

Diterpenes from Marrubium sericeum, Marrubium supinum and Marrubium alysson

From some Marrubium species endemic in the Iberian Peninsula, four new diterpenoids, 6-acetyl-marrubenol, 19-acetyl-marrubenol, premarrubenol and 6-acetyl-premarrubenol, have been isolated. The previously known diterpenes marrubiin and marrubenol have also been obtained from the same sources.     

Sesquiterpenoid and acetylenic constituents of seven Clibadium species

The investigation of seven Clibadium species resulted in the isolation of a new germacrolide from C. surinamense, trans-β-bergamotene, a new sesquiterpene from C. asperum and a new C-17 acetylenic alcohol from C. glomeratum. Five known acetylenic compounds were present in some members of the genus. In good agreement with morphological data, the presence of ichthyothereol and its acetate in several members of Clibadium suggest affiliation with the genus Ichthyothere within the subtribe Milleriinae (Heliantheae-Compositae).     

Chromenes from ageratina riparia

The reinvestigation of the roots and aerial parts of Ageratina riparia afforded ten new chromenes, their structures being determined by spectral data and chemical transfomrations.     

Arenophthalide A: A new phthalide glycoside from Helichrysum arenarium roots

Spectral data and degradations were used to determine the structure of arenophthalide A, a glycoside of the formula C₁₉H₂₄O₉, isolated from the roots of Helichrysum arenarium. Structure I was assigned to the compound.     

Diterpenoids from Baccharis tola

Erythroxylol-A, oleanolic acid, erythroxylol-A oxide, scopolatine, 4-hydroxy-3-methoxyacetophenone and two new diterpenes, ent-beyer-14-en-18-ol and 19-hydroxy-13-epimanoyl oxide, were isolated from B. tola.     

Seven guaianolides from Eupatorium chinense

Two allyl hydroperoxy guaianolide sesquiterpene lactones (peroxyeupahakonin-A and -B) and five new guaianolides (eupahakonin-A and -B, eupahakonenin-A and -B, and eupahakonesin) were isolated from E. chinense and characterized. The allyl hydroperoxy sesquiterpene lactones were characterized by spectral and chemical methods. They were prepared chemically by photosensitized oxygenation of eupahakonin-A.     

Coumarin-hemiterpene ethers from Artemisia species

In addition to a known derivative, five new coumarin-hemiterpene ethers were isolated from the leaves of Artemisia laciniata, A. armeniaca and A. tanacetifolia and identified by ¹H NMR and, in part, by ¹³C NMR spectroscopy. The coumarin patterns are characterized particularly by compounds with a hydroxylated and saturated isoprenoid unit attached to oxygen at the C-8 position and by 5,7,8-trioxygenated derivatives. The chemotaxonomic significance of the coumarin-terpenoid ethers within Artemisia is discussed.     

Anthocyanins in Salix species: A new anthocyanin in salix purpurea bark

Cyanidin 3-glucoside and delphinidin 3-glucoside (minor component) occurred in the bark of Salix purpurea (29 cultivars examined), S. fragilis (3 cvs), S. americana (4 cvs), S. rubra (1 cv.), S. incana (1 cv.), S. aegyptica (1 cv.) and S. alba (3 cvs) and several hybrids. A previously unrecorded anthocyanin was also present in appreciable amounts in the bark of eleven S. purpurea cultivars, notably those with small leaves. In other large-leaved cultivars of S. purpurea (18) it occurred only in traces or was not detected with certainty. A trace was found in one purpurea hybrid, but it was not detected in four others. Small amounts of the new anthocyanin were also found in S. incana (1 cv.), S. fragilis cv. Basfordiana, S. americana cv. Cordata and one hybrid, but were absent from other cultivars of S. fragilis (2) and S. americana (2), and also from S. alba (3), S. aegyptica (1), S. daphnoides (1), S. rubra (1), S. triandra (1), S. viminalis (1) and three hybrids. The new anthocyanin is unique in containing fructose as well as glucose and is based upon a previously undescribed anthocyanidin, possibly dimeric in nature, which is provisionally named purpurinidin.     

Flavonoid constituents of Eupatorium odoratum

Isosakuranetin and a new chalcone, odoratin, have been isolated from the leaves of Eupatorium odoratum. The structure of odoratin has been shown to be 2′-hydroxy-4,4′,5′,6′-tetramethoxy chalcone.     

Xanthones and C-glucosylflavones from Gentiana corymbifera

A new xanthone and twelve known compounds were isolated from the aerial parts of Gentiana corymbifera. The new xanthone was shown to be 3-methylcorymbiferin (1,8-dihydroxy-3,4,5-trimethoxy-9H-xanthen-9-one) by spectral and chemical procedures. The chemotaxonomic implications are discussed.     

Diterpenes with a new carbon skeleton from Printzia Laxa

The aerial parts of the South African composite Printzia laxa contain two manoyl oxides and three clerodane derivatives together with two further acids, which belong to a new type of diterpene, biogenetically closely related to the clerodanes. The structures have been elucidated by spectroscopic methods. The constituents may indicate some relationship of Printzia to the tribe Astereae.     

Diterpenoids from Acacia leucophloea

From the root bark of Acacia leucophloea (Mimosaceae) two new pimar-8(14)-ene diterpenoids have been isolated. Their structures have been established by chemical and spectroscopic means as 1β,15R,16-trihydroxypimar8(14)-ene(leucophleol) and 15R,16-epoxy-1β,11α-dihydroxypimar-8(14)-ene(leucophleoxol).     

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.     

Two labdane diterpenoids from Nicotiana raimondii

Two new labdanoids from Nicotiana raimondii have been identified as (12E) - 7β - hydroxylabda - 8(20),12,14 - triene and 7β - hydroxy - labda - 8(20),13(16),14 - triene.     

Depsipeptides from Metarhizium anisopliae

From the culture medium of a strain of Metarhizium anisopliae, 14 depsipeptides have been isolated. Five of them were identified as known destruxins A, B, C, D and desmethyldestruxin B. The structures of the new compounds, named destruxins E, A₁, A₂, B₁, B₂, C₂, D₁, D₂ and E₁,were established mainly from the mass spectral analysis of their corresponding open-chain derivatives.     

(8R,14S)-8-angeloyloxythapsan-14-ol,a sesquiterpene with a novel carbon skeleton,from Thapsia villosa

The roots of Thapsia villosa afforded in addition to other terpenoids, a sesquiterpene, with a new carbon skeleton. The structure, including the relative configuration, was elucidated by spectroscopic methods, a few chemical transformations and by X-ray analysis. The absolute configuration was determined by means of the method of Horeau. The trivial name thapsan is suggested for the parent structure [2aR,2bR,6aS,7aS]-2b,3,3,6a-tetramethylperhydroindeno[2,3-c]-furan.