桑叶中的黄酮类化合物

为了研究桑叶的化学成分与生物活性之间的相关性, 采用硅胶、Sephadex LH-20、RP-C₁₈等色谱方法分离纯化, 通过核磁共振谱、质谱等波谱分析手段鉴定化合物结构。从长穗桑的95%乙醇提取物中分离到4个Diels-Alder类加合物, 分别鉴定为mulberrofuran F₁ (1)、mulberrofuran F (2)、chalcomoracin (3) 和kuwanon J (4); 2个查耳酮类化合物, 鉴定为morachalcone A (5) 和isobavachalcone (6); 3个黄酮类化合物, 鉴定为 norartocarpetin (7)、kuwanon C (8) 和6-geranylapigenin (9)。化合物1和6为首次从该种植物中分离, 化合物4～5、7～9为首次从桑叶中分离得到, 其中化合物1为新化合物。采用MTT法对化合物1～5进行了抗肿瘤活性筛选, 结果显示化合物1～3对人肿瘤细胞A549、Bel7402、BGC823、HCT-8以及A2780具有抑制作用。     

不同产地桑叶药材UPLC指纹图谱研究

目的 建立不同产地桑叶UPLC指纹图谱.方法 采用ACQUITY UPLC BEH C18（2.1 mm×50.0 mm,1.7 μm）色谱柱,流动相为甲醇-0.2％磷酸水溶液,梯度洗脱,检测波长为358 nm,流速为0.6 ml/min,柱温40℃,进样体积1μl.结果 建立了桑叶专属性的UPLC指纹图谱,确定了15个共有峰,不同产地桑叶样品具有较好的相似度.结论 UPLC指纹图谱方法重复性好,简便可靠,可用于桑叶的快速鉴别,可以为桑叶的质量控制和市场应用提供依据.     

Two new 5,8-quinoflavans from the leaf of Ilex centrochinensis

Two new 5,8-quinoflavans were isolated from the leaf of Ilex centrochinensis, and their structures were elucidated as (2R)-7,3′,4′-trimethoxy-5,8-quinoflavan and (2S)-7-methoxy-4′-hydroxy-5,8-quinoflavan on the basis of spectroscopic methods, especially 1D and 2D NMR, CD, and mass spectral analyses. Both of them exhibited weak cytotoxic activity against HuH7 cell lines and no cytotoxic activity against CaCO-2 cell lines.     

A new para-quinone-type flavan from the leaves of Ilex centrochinensis and its anti-inflammatory activities

A new para-quinone-type flavan, (2S)-7-methoxy-3′,4′-dihydroxy-5,8-quinoflavan (1), together with three known compounds, were isolated from the leaves of Ilex centrochinensis. Their structures were elucidated by detailed spectroscopic analyses for new structure and in comparison with published data for known compounds. Moreover, the new compound was evaluated its cytotoxic and anti-inflammatory activities in vitro on LPS induced RAW 264.7 cells and the results showed that 1 has promising anti-inflammatory activities.     

桑叶降糖活性成分研究

目的对桑叶(MorusalbaL.)的活性部位进行化学成分研究。方法用色谱法分离,用波谱法对化合物结构进行鉴定。结果与结论从桑叶活性部位中分出10个化合物,其结构分别为:1-脱氧野尻霉素(1-de-oxynojirimycin,1)、fagomine(2)、1,4-二脱氧-1,4-亚氨基-D-阿拉伯醇(1,4-deoxy-1,4-imino-D-arabinitol,3)、精氨酸醋酸盐(arginineacetate,4)、槲皮素-3-O-β-D-吡喃葡萄糖苷(quercetin3-O-β-D-glucopyranoside,5)、芦丁(rutin,6)、咖啡酸乙酯(caffeicacidethylester,7)、山柰酚-3-O-β-D-吡喃葡萄糖苷(kaempferol-3-O-β-D-glucopy-ranoside,8)、山柰酚-3-O-(6″-O-α-L-鼠李糖基)-β-D-吡喃葡萄糖苷[kaempferol-3-O-(6″-O-α-L-rhamnosyl)-β-D-glucopyranoside,9]、槲皮素(quercetin,10)。桑叶活性部位化学成分主要为生物碱和黄酮类,其中化合物7为首次从该属植物中分得。     

桑白皮黄酮化学成分的研究

目的分离并鉴定桑白皮Morus alba L.丙酮提取物的化学成分.方法利用各种色谱方法进行分离纯化,根据理化性质和光谱数据进行结构鉴定.结果得到4个化合物,分别鉴定为2',4',5-三羟基-3-(y,y,γ-羟基-二甲基)丙基-2″,2″-二甲基吡喃-5″,6″:6,7-黄酮(1,morusignin L)、6,4'-二甲氧基-5,7,3'-三羟基异黄酮(2)、7-甲氧基-5,4'-二羟基二氢黄酮醇(3)、6-甲氧基-5,7,4'-三羟基异黄酮(4).结论化合物2、3、4为首次从该植物中分离得到.     

桑白皮抗病毒有效成分的提取分离及体外抗病毒活性研究

目的研究桑白皮中化学成分的抗病毒作用。方法利用细胞病变方法进行体外抗病毒筛选试验。结果桑白皮中分离得到的化合物1和化合物3在体外有较好的抑制副流感病毒、流感病毒的致病作用;化合物1具有抗呼吸道合胞病毒作用,延缓腺病毒Ⅲ、HSV Ⅰ致病作用;化合物2和化合物5也有部分抗病毒作用;化合物4能抑制腺病毒Ⅲ、柯萨奇病毒B3 、HSV Ⅰ、副流感病毒的致细胞病变作用。结论桑白皮提取物对呼吸道常见病毒有抑制作用。     

Flavans from the leaf of Ilex centrochinensis

Phytochemical investigation of the leaf of Ilex centrochinensis led to the isolation and characterization of four flavans, one flavanone (5), and one flavone (6), including a new compound whose structure was elucidated as (2S)-5,3′,4′-trihydroxy-7-methoxyflavan (1) and a new natural product whose structure was elucidated as (2S)-5-hydroxy-7,3′,4′-trimethoxyflavan (4) on the basis of spectroscopic methods especially 1D and 2D NMR, CD, and mass spectral analyses. Compounds 1 and 4 exhibited weak cytotoxic activity against Huh7 cell line and no cytotoxic activity against Caco-2 cell line.     

A novel sulphur glycoside from the seeds of Descurainia sophia (L.)

A new sulphur glycoside, named descurainoside (1), and the known compound sinapic acid (2) have been isolated from the seeds of Descurainia sophia (L.) Webb ex Prantl. The structure of 1 has been identified as (1R,6S,8R,9S,10S)-9,10-dihydroxy-4-[(4-hydroxy-3,5-dimethoxyphenyl)methylene]-8-(hydroxymethyl)-2,7-dioxa-5-thiabicyclo[4.4.0]decan-3-one by means of physico-chemical properties and spectroscopic methods (1D and 2D NMR, HRMS, ESI-MS).     

A novel sulphur glycoside from the seeds of Descurainia sophia (L.)

A new sulphur glycoside, named descurainoside (1), and the known compound sinapic acid (2) have been isolated from the seeds of Descurainia sophia (L.) Webb ex Prantl. The structure of 1 has been identified as (1R,6S,8R,9S,10S)-9,10-dihydroxy-4-[(4-hydroxy-3,5-dimethoxyphenyl)methylene]-8-(hydroxymethyl)-2,7-dioxa-5-thiabicyclo[4.4.0]decan-3-one by means of physico-chemical properties and spectroscopic methods (1D and 2D NMR, HRMS, ESI-MS).     

Aromatic acid derivatives from the lateral roots of Aconitum carmichaelii

Seven new aromatic acid derivatives (1–7), together with five known analogs, were isolated from the lateral roots of Aconitum carmichaelii. Structures of the new compounds were determined by spectroscopic and chemical methods as 4-methyl ( ? )-(R)-hydroxyeucomate (1), 4-butyl ( ? )-(R)-hydroxyeucomate (2), 4-butyl-1-methyl (+)-(R)-2-O-(4′-hydroxy-3′-methoxybenzoyl)malate (3), 1-butyl-4-methyl (+)-(R)-2-O-(4′-hydroxy-3′-methoxybenzoyl)malate (4), dimethyl (+)-(R)-2-O-(4′-hydroxy-3′-methoxybenzoyl)malate (5), dimethyl (+)-(R)-2-O-(4′-hydroxybenzoyl)malate (6), and methyl ( ± )-3-(4′-hydroxy-3′-methoxyphenyl)-3-sulfopropionate (7), respectively. Compounds 1 and 2 are 2-benzylmalates (eucomate derivatives), 3–6 belong to 2-O-benzoylmalates, and 7 is a rare phenylpropionate containing a sulfonic acid group. The absolute configurations of eucomate derivatives were confirmed by X-ray crystallographic analysis of 4-methyl eucomate (11).     

A novel analgesic pyrazine derivative from the leaves of Croton tiglium L.

A novel analgesic pyrazine derivative, named crotonine, was isolated from the leaves of Croton tiglium L. The structure was elucidated as 2-(furan-2-yl)-5-(2,3,4-trihydroxy-butyl)-1,4-diazine by spectroscopic analysis. Crotonine inhibited remarkably the acetic acid-induced writhing in mice.     

Cytotoxic C-Methylated Chalcones from Syzygium samarangense.

Abstract

The flavonoids 2′-hydroxy-4′,6′-dimethoxy-3′-methylchalcone (1), 2′,4′-dihydroxy-6′-methoxy-3′,5′-dimethylchalcone (2), 2′,4′-dihydroxy-6′-methoxy-3′-methylchalcone (3), 2′,4′-dihydroxy-6′-methoxy-3′-methyldihydrochalcone (4) and 2′,4′-dihydroxy-6′-methoxy-3′,5′-dimethyldihydrochalcone (5), isolated from Syzygium samarangense. (Blume) Merr. & L.M. Perry (Myrtaceae), were subjected to cytotoxicity testing using the dimethylthiazoldiphenyl tetrazolium (MTT) assay. The cell lines used were the Chinese hamster ovarian (CHO-AA8) and the human mammary adenocarcinoma, (MCF-7 and SKBR-3). Among the test compounds, 2 exhibited significant differential cytotoxicity against the MCF-7 cell line with an IC₅₀ of 0.0015 ± 0.0001 nM. It was also cytotoxic against the SKBR-3 cell line with an IC₅₀ of 0.0128 ± 0.0006 nM. Doxorubicin, the positive control, had an IC₅₀ of 2.60 ± 0.28 × 10^?4 nM against the MCF-7 cell line and an IC₅₀ of 2.76 ± 0.52 × 10^?5 nM against the SKBR-3 cell line. When tested in a mechanism-based yeast bioassay for detecting DNA-damaging agents using genetically engineered Saccharomyces cerevisiae. RS322Y (RAD52) mutant strain and (LF15/11) (RAD+) wild-type strain, 2 showed significant selective cytotoxicity against the RAD52 yeast mutant strain. It had an IC₁₂ of 0.1482 nM, as compared with the positive control, streptonigrin, which had an IC₁₂ of 0.0134 nM. Hence, 2 is a cytotoxic natural product with potential anticancer application.     

Two new compounds from Trifolium resupinatum var. microcephalum

An investigation of CH₂Cl₂ and EtOH extracts of Trifolium resupinatum L. var. microcephalum Zoh. has led to the isolation of two new compounds characterized as 4,15-dimethyl-2-(1,2-dihydroxyethyl)-hexadecene (1) and 1-undecene-1-O-β-2′,3′,4′,6′-tetraacetyl glucopyranoside (2a). Their structures were established by 1D and 2D NMR techniques, and mass spectroscopy.     

Enantioselective synthesis of tri-deuterated (–)-geosmin to be used as internal standard in quantitation assays

For the accurate and sensitive quantitation of the off-flavor compound geosmin, particularly in complex matrices, a stable isotopologue as internal standard is highly advantageous. In this work, we present a versatile synthetic strategy leading from (4aR)-1,4a-dimethyl-4,4a,5,6,7,8-hexahydronaphthalen-2(3H)-one to tri-deuterated (–)-geosmin ((4S,4aS,8aR)-4,8a-dimethyl(3,3,4-²H₃)octahydronaphthalen-4a(2H)-ol). The starting material was readily accessible from inexpensive 2-methylcyclohexan-1-one using previously published procedures.     

A novel analgesic pyrazine derivative from the leaves of Croton tiglium L.

A novel analgesic pyrazine derivative, named crotonine, was isolated from the leaves of Croton tiglium L. The structure was elucidated as 2-(furan-2-yl)-5-(2,3,4-trihydroxy-butyl)-1,4-diazine by spectroscopic analysis. Crotonine inhibited remarkably the acetic acid-induced writhing in mice.     

Anti-inflammatory coumarins from Paramignya trimera

Context: Paramignya trimera (Oliv.) Burkill (Rutaceae) has been used to treat liver diseases and cancer. However, the anti-inflammatory effects of this medicinal plant and its components have not been elucidated.

Objective: This study investigated chemical constituents of the P. trimera stems and evaluated anti-inflammatory effects of isolated compounds.

Materials and methods: Cytotoxicity of isolated compounds (5–40?μM) toward BV2 cells was tested using 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) for 24?h. Inhibitory effects of isolated compounds (5-40?μM) on nitrite and PGE₂ concentrations were determined using Griess reaction and PGE₂ ELISA kit, respectively (pretreated with the compounds for 3?h and then stimulated for 18?h with LPS). Inhibitory effects of compounds (5-40?μM) on iNOS and COX-2 protein expression were evaluated by Western blot analysis (pretreated with the compounds for 3?h and then stimulated for 24?h with LPS).

Results: Seven coumarins were isolated and identified as: ostruthin (1), ninhvanin (2), 8-geranyl-7-hydroxycoumarin (3), 6-(6′,7′-dihydroxy-3′,7′-dimethylocta-2′-enyl)-7-hydroxycoumarin (4), 6-(7-hydroperoxy-3,7-dimethylocta-2,5-dienyl)-7-hydroxycoumarin (5), 6-(2-hydroxyethyl)-2,2-dimethyl-2H-1-benzopyran (6), and luvangetin (7). Compounds 1–4 and 7 inhibited NO and PGE₂ production in LPS-stimulated BV2 cells, with IC₅₀ values ranging from 9.8 to 46.8 and from 9.4 to 52.8?μM, respectively. Ostruthin (1) and ninhvanin (2) were shown to suppress LPS-induced iNOS and COX-2 protein expression.

Discussion and conclusion: The present study provides a scientific rationale for the use of P. trimera in the prevention and treatment of neuroinflammatory diseases. Ostruthin and ninhvanin might have potential therapeutic effects and should be considered for further development as new anti-neuroinflammatory agents.     

A new saponin from the leaves and stems of Panax quinquefolium L. collected in Canada

A new dammarane-type saponin named quinquenoside L3 (1) together with vina-ginsenoside R3 (2) were isolated from the leaves and stems of Panax quinquefolium L. collected in Canada. On the basis of physicochemical and spectral evidences, 1 was established as 3-O-β-D-glucopyranosyl-20-O-[β-D-xylopyranosyl-(1 → 6)-β-D-glucopyranosyl] 20(S)-dammar-23-ene-3β, 12β,20,25-tetryol.     

Structural elucidation of a new flavone from Sarcopyramis nepalensis

A novel flavone, named 4′-methoxy-3′,5,7-trihydroxy-8-(1″-(3?,4?,5?-trihydroxyphenyl)ethyl)flavone (1), was isolated from Sarcopyramis nepalensis, along with two known compounds syringaresinol (2) and aralidioside (3). Their structures were established by the spectroscopic analysis, especially by 2D NMR. All of the three compounds were isolated from the plant for the first time.     

Ceramides and cerebrosides from the marine bryozoan Bugula neritina inhabiting South China Sea

From the marine bryozoan Bugula neritina inhabiting South China Sea, a new ceramide named (2S,3R,4E)-2-(14′-methyl-pentadecanoylamino)-4-octadecene-l,3-diol (1) and a new cerebroside named 1-O-(β-d-glucopyranosyl)-(2S,3R,4E)-2-(heptadecanoylamino)-4-octadecene-l,3-diol (6), together with one known ceramide (2) and three known cerebrosides (3, 4, and 5), were isolated. Their structures were deduced by extensive spectral analysis and chemical evidences. Compound 1 is branched with a methyl [–CH(CH₃)₂] in the fatty acid moiety, which is a rare structural feature among ceramides. Compound 6 is a new cerebroside with 17 carbons in the fatty acid moiety, while 5 is a new natural product which was isolated from a natural origin for the first time.