靛红席夫碱及其Cu(Ⅱ)/Zn(Ⅱ)配合物的合成与抗稻瘟菌活性研究

以靛红为原料合成了系列席夫碱类化合物及其cu(Ⅱ)、Zn(Ⅱ)配合物,研究了它们在抗稻瘟菌方面的活性,发现靛红及其席夫碱类化合物没有好的抑制稻瘟菌孢子萌发的活性,而其Cu(Ⅱ)、Zn(Ⅱ)配合物具有较好的活性,其中双靛红席夫碱的Cu(Ⅱ)的活性接近Carbendazim的水平。     

New bioactive constituents from eleutherine americana

Three new constituents were isolated from Eleutherine americana Merr. et K. Heyne (hong-cong) by means of silica gel, octadecyl silane (ODS) column chromatography and high-performance liquid chromatography (HPLC). They were identified as (1) 9,9′-dihydroxy-8,8′-dimethoxy-1′-dimethyl-1H, 1H′-[4,4′]bis[naphtha[2,3-c] funanyl]-3,3′-dione; (2) 6,8-dihydroxy-3,4-dimethoxy-1-methyl-anthraquin-one-2-carboxylic acid methyl ester; and (3) 2-acetyl-3,6,8-trihydroxy-1-methyl anthraquinone by the physico-chemical properties and spectral data, respectively. All three compounds showed weak activities against the growth of Pyricularia oryzea. The minimum morphological deformation concentration (MMDC) was 145.8, 50.2, and 124.8 μg/mL. Additionally, (2) also inhibited the proliferation of human erythroleukemia cancer cell line K562 with IC₅₀ value of 49.1 μg/mL. __________ Translated from Chemical Journal of Chinese Universities, 2005, 26(11) (in Chinese)     

Application of MEKC and monolithic CEC for the analysis of bioactive naphthoquinones in Eleutherine americana

Two microscale separation techniques for the analysis of bioactive naphthoquinones in Eleutherine americana were developed and validated. By MEKC four compounds (eleuthoside B, isoeleutherin, eleutherol and eleutherinoside A) could be determined in plant extracts using an aqueous electrolyte solution composed of 25 mM sodium tetraborate, 50 mM sodium cholate and 20% THF. CEC on a polymeric methacrylate‐based monolith with strong cationic properties showed promising results, as it additionally enabled the separation of two enantiomers, eleutherin and isoeleutherin. The mobile phase for CEC experiments comprised 3 mM ammonium formate in a mixture of ACN and water. At an applied voltage of ?25 kV, all five markers were baseline separated in less than 12 min. Both methods were successfully validated for linearity (MEKC: R²≥0.999; CEC: R²≥0.997), sensitivity (MEKC: LOD=4–5 μg/mL; CEC: LOD=2–8 μg/mL), accuracy (MEKC: 96.5–102.7% recovery; CEC: 97.1–103.5% recovery) and precision (MEKC: σ_rel≤2.43%; CEC: σ_rel≤2.21%). The quantitative analysis of naphthoquinone derivatives in several E. americana samples showed that both methods are suitable for practical applications, because the results were well comparable to those obtained by established techniques such as HPLC.     

A New Furostanol Saponin from Dioscorea futshauensis

A new furostanol saponin presenting moderate bioacitivity of inducting morphological deformation of Pyricularia oryzae mycelia was isolated from Dioscorea futshauensis R.Kunth by bioacitivity-guided fractionation. The structure was established as 26-O-β-D-glucopyranosyl-3β,26-diol-23(S)-methoxyl-(25R)-furost-5,20(22)-diene-3-O-[α-L-rhamnopyranosyl(1→2)-β-D-glucopyranosyl(1→3)]-β-D-glucopyranoside on the basis of chemical evidencesand spectral analysis,especially by 2D-NMR techniques.     

A New Pregnane Glycoside from Fermented Leaves of Agave americana

A new minor pregane glycoside was isolated from the fermented leaves of Agave americana.Its structure was elucidated as (20S)-5α-pregnane-3β，20-diol 20-O-β-D-glucopyrano-side(1)by spectral methods.     

A New Spirostanol Saponin from Dioscorea futshauensis

A new screening bioassay detecting deformation of mycelia germinated from conidia of Pyricularia oryzae P-2b was first developed for quantitative application to screen antifungal and antineoplastic agents by H. Kobayashi1,2. We have introduced and applied this bioassay in the search of bioactive agents from Traditional Chinese Medicine3,4. The ethanol extract of Dioscorea futshauensis R. Kunth (Dioscoreaceae) showed a strong activity against the growth of Pyricularia oryzae P-2b. Its buta…     

Two New Steroidal Glycosides from Fermented Leaves of Agave americana

Two new spirostanol glycosides named agamenoside A and B, ere isolated from the fermented leaves of Agave americana. Their structures were elucidated as (23S,25R)-5α-spirostan-3β,6α，23－triol 3-O-α-L-rhamnopyranosyl-(1→3)-β-D-glucopyranosyl-(1→2)-[β-D-xylopyranosyl-(1→3)]-β-D-glucopyranosyl-(1→4)-β-D-galactopyranoside(1) and (25R)-5α-spiro-stan-3β,6α-diol 3-O-β-D-glucopyranosyl-(1→2)-[β-D-xylopyranosyl-(1→3)]-β-D-glucopyra-nosyl-(1→4)-β-D-galactopyranoside(2) by a combination of chemical and spectral methods.     

The chemical constituents from the active fractions of Eleutherine bulbosa with their antimicrobial activity

Abstract

Six compounds including three new polyketide ones named eleubosas A-C (1–3) were isolated from the active frations of Eleutherine bulbosa. Their structures were elucidated by extensive spectroscopic methods, including NMR, MS and IR spectroscopic analyses data. All the isolates were evaluated against three pathogenic bacteria, Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa, and the results showed that compounds 1 and 2 displayed moderate inhibitory activities against E. coli with MIC values both 12.5?μg/mL, which are consistent with the clinical applications and need further studies.     

A New Triterpenoid Spaonin Isolated from the Seeds of Aesculus assamica Griff

The Aesculus genus consists of about thirty species distributed in Asia, Europe andAmerica. There are sixteen species distributed in China, and most of them are used asherbal medicines for the treatment of distention and pain in the chest and abdomen. Anu…