摘要:

A total of 8 purified 7, 9′, 7′, 9-bisepoxylignans were evaluated for bronchodilatory effect. (+)-Phillygenin was the most potent lignan and it relaxed the guinea-pig isolated tracheal chain preparation dose-dependently. The lignans potencies were compared by EC50values.

ISSN:1057-5634    

DOI:10.1080/10575639608044888

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Manipulation of the secondary metabolite pattern was studied by feeding various compounds into growing cultures of the streptazolin (1)-producing organismStreptomyces sp.(strain FH-S 2184). Besides an increase of the yield of (1),caused by a number of primary metabolites exclusively, the feeding of ammonium ions initiated the biosynthesis of the obscurolides A2(2) and A3(3).

ISSN:1057-5634    

DOI:10.1080/10575639608044889

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

A new kaurane diterpene was isolated and identified as the major HIV-inhibitory constituent of the aqueous extract of fruits of aXylopiasp. plant. Analysis of spectral data revealed the structure of the compound, xylopinic acid (1), a new diastereomer of a compound previously known only as a chemical/microbial transformation product.

ISSN:1057-5634    

DOI:10.1080/10575639608044890

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Treatment of suspension-cell cultures ofSanguinaria canadensisL. (SCP-GM) with a series of natural and synthetic retinoic acid derivatives induced benzophenanthridine alkaloid biosynthesis in a dose-dependent manner. Suspension cells were treated with one of the following: retinoic acid (RA), retinol (ROH), retinal (RHO). 13-cis-retinoic acid (cis-RA), or retinyl acetate (ROAc) in concentrations ranging from 1 to 50 μM (24 h). Each of the RA derivatives tested increased the cellular alkaloid concentrations of sanguinarine and chelerythrine by 97 to 470% (approximately 0.045–0.23% dry wt) depending on the réinoid and the dosage employed. Control SCP-GM suspension-cells accumulated only trace amounts of sanguinarine and chelerythrine, approximately 0.005% dry wt and 0.004% dry wt, respectively. The activity of S-adenosyl methionine: tetrahydroberberine-.V-methyltransferase, a key branch point enzyme in the benzophenanthridine biosynthetic pathway, was also induced over 24 h after treatment of the cells with RA (10 μM). RA-induction of benzophenanthridine alkaloid biosynthesis was significantly suppressed by pretreating the suspension cells with actinomycin D (5 μg/ml), α-amanatin (20 μg/ml) or cycloheximide (1 μg/ml) for 1 h. The results from this work demonstrate that retinoid-induction of benzophenanthridine alkaloid biosynthesis is similar to that of fungal elicitation, and therefore these compounds may be useful for investigating the elicitation response.

ISSN:1057-5634    

DOI:10.1080/10575639608044891

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Irradiation of isoperezone acetate (4) by ultraviolet light yielded the cycloaddition products 5, 6 and the ene-type product 7.

ISSN:1057-5634    

DOI:10.1080/10575639608044892

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

From the aerial parts ofTeucrium nudicauleH. the previously known diterpenoids 6-acetilteucjaponin B and triacetylteumassilin have been isolated together with the new C-12 epimer of teupyreinin as well as the flavones cirsiliol and eupatorin. FromBaccharis spicata(Lam) Beill., theneo-clerodane bacchotricuneatin A and 6α-hydroxybacchotricuneatin A were isolated. Some of these compounds have been subjected to a series of chemical transformations in order to study the structure-antifeedant activity relationship againstTenebrio molitor(Coleoptera, Tenebrionidae) larvae.

ISSN:1057-5634    

DOI:10.1080/10575639608044893

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Tyrosol and five bioactive diketopiperazines,cyclo-(L-prolyl-L-glycine),cyclo-(L-prolyl-L-valine),cyclo-(L-leucyl-L-proline),cyclo-(L-tirosil-L-proline) andcyclo-(L-alanil-L-proline) were isolated from the phytopathogenic fungusPestalotia palmarum.

ISSN:1057-5634    

DOI:10.1080/10575639608044894

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

An antitumor cytotoxicity-bioassay directed fractionation and separation of the ethanol extract ofGoniothalamus amuyonled to the isolation of three highly cytotoxic polyketides, gigantriocin (1), corossolin (2) and annonacin (3) against three human tumor cell lines. The stereochemistry was proposed on the basis of extensive NMR analysis and biogenetic pathways.

ISSN:1057-5634    

DOI:10.1080/10575639608044895

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The natural diterpenoid sclareol (1) and ten of its analogs (2–11) were tested for their antiinsectan activity against the fall armywormSpodoptera frugiperda.Two of the tested analogs, 2-keto-sclareol (3) and 8α, 13β-dihydroxy-labd-14-en-18-O-β-D-glucoside (10), showed significant activity.

ISSN:1057-5634    

DOI:10.1080/10575639608044896

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

A new synthesis of the drimane sesquiterpene 1has been performed using (-)drimenol (3)as chiral starting material. Comparison of the specific rotation of the natural and synthetic 1established the absolute configuration of the naturally occurring 1as the normal drimane skeleton.

ISSN:1057-5634    

DOI:10.1080/10575639608044897

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor