摘要:

Three tetraoxygenated xanthones, 1,6-dihydroxy-3,5-dimethoxyxanthone, 3-hydroxy-1,5,6-trimethoxyxanthone and 1,3,5-trihydroxy-2-methoxyxanthone, were isolated for the first time from the aerial parts ofC. erythraea. Their structures were established by spectroscopic means and by comparison with literature references.

ISSN:1057-5634    

DOI:10.1080/10575630008043763

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Nyctinastic leaf-movement of the plant is controlled by a biological clock. The most difficult problem encountered in the chemical studies of nyctinasty, is the isolation of chemical signals controlling this movement. Now, we have established a good procedure for isolation of the chemicals causing leaf-movement. The separation of two inversely bioactive substances, causing leaf-closing and opening movement, by Amberlite XAD-7 chromatography was very effective. Final separation with HPLC using a combination of plural ODS columns enabled us to isolate the highly polar ieaf-closing and -opening substances ofAlbizzia julibrissin Durazz.

ISSN:1057-5634    

DOI:10.1080/10575630008043764

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Penicillium piscarium VKM F-961 produces two new polycyclic diketopiperazine alkaloids, piscarinines A (1) and B (2) displaying moderate cytotoxicity. Their structures were established by MS and NMR investigations.

ISSN:1057-5634    

DOI:10.1080/10575630008043765

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

The new natural products, streptoketol A (1) and B (2), were discovered by chemical screening as secondary metabolites ofStreptomyces sp.(strain GT 051243). The absolute stereochemistry of1was deduced by Helmchen's method and CD spectroscopy. The streptoketols show DNA-binding properties which were observed with a recently developed method using thin-layer chromatography (bio-molecular-chemical screening).

ISSN:1057-5634    

DOI:10.1080/10575630008043766

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Two new ecdysteroids have been isolated from the mature ovaries of the silkworm,Bombyx mori.Their structures were established to be (23S)-2,22-dideoxy-23-hydroxyecdysone and its 3-phosphate on the basis of spectroscopic analysis including1H-NMR comparison with the known compounds, 2-deoxy-ecdysone and (23R)-and (23S)-23,25-dihydroxycholesterols.

ISSN:1057-5634    

DOI:10.1080/10575630008043767

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

A new spirostanol steroidal saponin, along with ten known saponins, which were based upon (25R)-spirost-5-en-3β-o1 (diosgenin) or (25R)-spirost-5-ene-3β5,17α-diol (pennogenin) as the aglycones, were isolated from the rhizomes ofParis polyphyllavar.chinensis. Spectral data, including two-dimensional NMR, and the result of hydrolytic cleavage showed that the structure of the new saponin was pennogenin 3-0-{O−α-L-rhamnopyranosyl-(1→4)-Oa-L-rhamnopyranosyl-(1→4)-β-D-glucopyranoside}. The isolated saponins were evaluated for their cytotoxic activity on human promyelocytic leukemia HL-60 cells.

ISSN:1057-5634    

DOI:10.1080/10575630008043768

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

A novel phenolic lipid, schimperiol (1), along with the polyol, iditol (2), have been isolated, purified and identified from the organic extract of the marine brown algaStypopodium schimperi, order Dictyotales. The structure of the new, unstable, natural product1was proposed on the basis of its NMR spectral data, and the spectral data of its acetylated derivative that was prepared by acetylation.

ISSN:1057-5634    

DOI:10.1080/10575630008043769

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Udoteal B (1), a geometrical isomer of udoteal, was isolated, along with udoteal (2), clionasterol and 28-isofucosterol, from the organic extract of the green algaUdotea petiolata. The structure of natural product1was proposed on the basis of its spectral data including 2D NMR experiments. The identification of the known metabolites was based on comparison of their spectral data with literature values.

ISSN:1057-5634    

DOI:10.1080/10575630008043770

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

A new natural product has been obtained from the roots of “Carrizo citrange” rootstocks(Citrus sinensis × Citrus trifoliata)infected by the nematodeTylenchulus semipenetrans, and its structure identified as the diterpene carnosic acid-11-methylether (1) on the basis of spectroscopic data and chemical means. The known compounds β-sitosterol (sterol), lupeol (triterpene), 5-hydroxy-3,7,3′,4′-tretramethoxy-flavone and 5-hydroxy-6,7,3′,4′-tetramethoxy-flavone (flavones), citracridone-I (alkaloid) and xanthyletin, nordentatin and poncitrin (chromenecoumarins), were isolated from the same source.

ISSN:1057-5634    

DOI:10.1080/10575630008043771

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Bioassay-guidied fractionation of an organic extract of a South African collection of the spongePellinasp. afforded six polyacetylenic metabolites. These were identified as pellynols A-D, pellynol F, and a new compound, pellynolI(1). The structure of1was elucidated by NMR and MS analyses and by comparison of its spectral data with related compounds. The six pellynols all exhibited cytotoxic activity against human tumor cell lines.

ISSN:1057-5634    

DOI:10.1080/10575630008043772

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor