A New Bibenzyl Derivative from Dendrobium moniliforme

A new bibenzyl derivative, 3,4-dihydroxy-4,5-dimethoxy bibenzyl, was isolated from a orchid Dendrobium moniliforme. The structure elucidation and 1H,13C NMR assignments were achieved by spectroscopic method.

A new bibenzyl derivative from Pleione bulbocodioides

A new bibenzyl derivative 1, named 2-（4＇＇-hydroxybenzy1）-3-（3＇-hydroxyphenethy1）-5-methoxy-cyclohexa-2,5-diene-1,4- dione, and two known stilbenoids （2, 3） were isolated from the tubers of Pleione bulbocodioides （Franch.） Rolfe. Their structures were elucidated by spectroscopic methods.

A New Bibenzyl Glycoside from Dendrobium moniliforme

A new bibenzyl glycoside has been isolated from the stems of Dendrobium moniliforme (L.) Sw. (Orchidaceae). Its structure has been identified on the basis of spectroscopic and chemical methods.

The bibenzyl derivatives of Dendrobium officinale prevent UV-B irradiation induced photoaging via SIRT3

Dendrobium officinale is a valuable medicinal herb that is widely used in traditional Chinese medicine.The chemical constituents of D.officinale have attracted much attention and a large number of compounds have been reported including many bibenzyl derivatives.13 bibenzyl derivatives from D.officinale were sent for molecular docking,sur-face plasmon resonance(SPR)assay and after detection of Mn-SOD and SIRT3 activities in or not in HaCaT cells,it was concluded that bibenzyl derivatives did not directly activate Mn-SOD but promoted SIRT3 proteins.In addition,HaCaT cells were irradiated with UV-B to induce an oxidative stress model in vitro to further verify the effect of bibenzyl derivatives.The results show that bibenzyl derivatives could directly bind to SIRT3,enhance the deacetylation and then activate Mn-SOD,so as to protect UV-B induced skin photoaging.

Rapid Identification of Bibenzyls of Stemona sessilifolia using Hyphenated LC-UV-NMR and LC-MS Methods

As a part of the ongoing search for new constituents of Stemona species in China, chemical investigation of Stemona sessilifolia, a plant used in the traditional Chinese medicine to treat respiratory disorders, was carried out. To identify the chemical components rapidly, a selected sample of S. sessilifolia containing bibenzyls was tested using LC-ESIMS and analyzed further using stop-flow LC-UV-NMR, which was sensitive for the detection of the main constituents. LC microfractions were collected using the LC-UV-NMR technique and HR-EIMS off-line analysis was cartied out on the collected fractions. This chemical screening strategy allowed for the on-line identification of the main constituents of S. sessilifolia and provided information that was useful for a further peak-guided isolation procedure. Using these methods, four bibenzyls were isolated： two known compounds, 3,5-dihydroxy-4-methyl bibenzyl（1） and 3, 5-dihydroxy-2＇-methoxy-4-methyl bibenzyl （ 2 ）, and two novel compounds, 3,3＇-dihydroxy-5, 6＇-dimethoxy bibenzyl（3） and 3,5-dihydroxy-2＇, 5＇-dimethoxy bibenzyl （4）.

Novel phenanthrene/bibenzyl trimers from the tubers of Bletilla striata attenuate neuroinflammation via inhibition of NF-κB signaling pathway

Five novel(9,10-dihydro)phenanthrene and bibenzyl trimers,as well as two previously identified biphenanthrenes and bibenzyls,were isolated from the tubers of Bletilla striata.Their structures were elucidated through comprehensive analyses of NMR and HRESIMS spectroscopic data.The absolute configurations of these compounds were determined by calculating rotational energy barriers and comparison of experimental and calculated ECD curves.Compounds 5b and 6 exhibited inhibitory effects on LPS-induced NO production in BV-2 cells,with IC_(50) values of 12.59±0.40 and 15.59±0.83μmol·L^(-1),respectively.A mechanistic study suggested that these compounds may attenuate neuroinflammation by reducing the activation of the AKT/IκB/NF-κB signaling pathway.Additionally,compounds 3a,6,and 7 demonstrated significant PTP1B inhibitory activities,with IC_(50) values of 1.52±0.34,1.39±0.11,and 1.78±0.01μmol·L^(-1),respectively.Further investigation revealed that compound 3a might inhibit LPS-induced PTP1B overexpression and NF-κB activation,thereby mitigating the neuroinflammatory response in BV-2 cells.

Structural diversification of bioactive bibenzyls through modular co-culture leading to the discovery of a novel neuroprotective agent

Bibenzyls,a kind of important plant polyphenols,have attracted growing attention for their broad and remarkable pharmacological activities.However,due to the low abundance in nature,uncontrollable and environmentally unfriendly chemical synthesis processes,these compounds are not readily accessible.Herein,one high-yield bibenzyl backbone-producing Escherichia coli strain was constructed by using a highly active and substrate-promiscuous bibenzyl synthase identified from Dendrobium officinale in combination with starter and extender biosynthetic enzymes.Three types of efficiently postmodifying modular strains were engineered by employing methyltransferases,prenyltransferase,and glycosyltransferase with high activity and substrate tolerance together with their corresponding donor biosynthetic modules.Structurally different bibenzyl derivatives were tandemly and/or divergently synthesized by co-culture engineering in various combination modes.Especially,a prenylated bibenzyl derivative(12)was found to be an antioxidant that exhibited potent neuroprotective activity in the cellular and rat models of ischemia stroke.RNA-seq,quantitative RT-PCR,and Western-blot analysis demonstrated that 12 could up-regulate the expression level of an apoptosis-inducing factor,mitochondria associated 3(Aifm3),suggesting that Aifm3 might be a new target in ischemic stroke therapy.This study provides a flexible plug-and-play strategy for the easy-to-implement synthesis of structurally diverse bibenzyls through a modular co-culture engineering pipeline for drug discovery.

Ramberg-Bcklund Rearrangement Approaches to the Synthesis of Natural Bibenzyls

The Ramberg-Bcklund rearrangement has been successfully utilized to convert readily available - and -hydrogen bearing substituted dibenzyl sulfones into corresponding stilbene derivatives, which is conveniently followed by hydrogenation in the presence of 10% Pd/C to afford the natural bibenzyls.

Antifungal variant bis(bibenzyl)s from the liverwort Asterella angusta

Bioassay-guided fractionation of the diethyl ether extract of the liverwort Asterella angusta led to the isolation of two antifungal bis（bibenzyl）s, riccardin I （1）, and angustatin A （2）. Their structures were established by spectroscopic analysis （1D NMR and 2D NMR, IR, MS）. Compound I is a novel variant riccardin-type bis（bibenzyl）, while compound 2 is the first nonheteratom-containing variant bis（bibenzyl） possessing a bibenzyl-phenanthrene skeleton.

Discrimination of the rare medicinal plant Dendrobium officinale based on naringenin, bibenzyl, and polysaccharides

The aim of this study was to establish a method for discriminating Dendrobium officinale from four of its close relatives Dendrobium chrysanthum, Dendrobium crystallinum, Dendrobium aphyllum and Dendrobium devonianum based on chemical composition analysis. We analyzed 62 samples of 24 Dendrobium species. High performance liquid chromatography analysis confirmed that the four low molecular weight compounds 4′,5,7-trihydroxyflavanone (naringenin), 3,4-dihydroxy-4′,5-dime- thoxybibenzyl (DDB-2), 3′,4-dihydroxy-3,5′-dimethoxybibenzyl (gigantol), and 4,4′-dihydroxy-3,3′,5-trimethoxybibenzyl (moscatilin), were common in the genus. The phenol-sulfuric acid method was used to quantify polysaccharides, and the monosaccharide composition of the polysaccharides was determined by gas chromatography. Stepwise discriminant analysis was used to differentiate among the five closely related species based on the chemical composition analysis. This proved to be a simple and accurate approach for discriminating among these species. The results also showed that the polysaccharide content, the amounts of the four low molecular weight compounds, and the mannose to glucose ratio, were important factors for species discriminant. Therefore, we propose that a chemical analysis based on quantification of naringenin, bibenzyl, and polysaccharides is effective for identifying D. officinale.

石斛属植物化学成分研究进展

石斛为珍贵中药材 ,应用历史悠久。现代药理研究表明石斛具有抗肿瘤、抗衰老及扩张血管等作用 ,其活性成分引起国内外的关注。该属植物的化学成分主要有生物碱、菲类、联苄类、芴酮、香豆素、倍半萜、多糖及挥发油。重点对近 15年来该属植物的主要活性成分进行了较系统的综述 ,为从石斛属植物中开发利用有药用价值的天然产物提供参考。

束花石斛化学成分研究

目的 :对束花石斛抗凝血活性部位乙酸乙酯部分进行化学成分研究。方法 :色谱和光谱分析法分离鉴定结构。结果 :从乙酸乙酯部分分离得到 9个化合物 ,分别鉴定为鼓槌联苄 (1)、玫瑰石斛素 (2 )、moscatilin(3)、dengibsin(4)、dendroflorin(5 )、大黄素 (6 ) ,大黄素甲醚 (7) ,大黄酚 (8)和 β 谷甾醇 (9)。 结论 :以上化合物除moscatilin外 。

鼓槌石斛化学成分的研究

目的 研究鼓槌石斛的化学成分 ,为阐明其活性成分 ,开发其资源提供科学依据。方法 采用胶柱层析法进行分离 ,根据光谱数据鉴定结构。结果 从中分得 10个化合物 ,分别为 :erianin( ) ,chrysotobibenzy( ) ,chrysotoxene( ) ,confusarin( ) ,erianthridin( ) ,dendroflorin( ) ,chrysotoxone( ) ,dengibsin( )和β- sitosterol( ) ,daucosterol( )。结论 化合物 为首次从石斛属植物中分得 ,化合物

鼓槌石斛化学成分的研究

目的 研究鼓槌石斛的化学成分,为阐明其活性成分,开发其资源提供科学依据。方法 采用硅胶柱层析法进行分离,根据光谱数据鉴定结构。结果 从中分得4个化合物,分别为;2,4,7-三羟基-9,10-二氢菲（Ⅰ）,2,7-二羟基-3,4,6-三甲氧基菲（Ⅱ）,5,4’-二羟基-3,3’二甲氧基联苄（Ⅲ）,3,4-二径基苯甲酸（Ⅳ）。结论 化合物Ⅰ-Ⅳ均为首次从石斛属植物中分得。

球花石斛的化学成分研究(Ⅰ)

目的 :研究兰科植物球花石斛的化学成分 ,以探明其有效成分并为制定中药石斛质量标准提供科学依据。方法 :采用硅胶、SephadexLH 2 0及RP C18等色谱技术分离纯化化合物 ,根据理化性质、光谱数据鉴定结构。结果 :从球花石斛乙醇提取物的乙酸乙酯部位分离得到芴酮类、联苄类、菲类及黄酮类 13个化合物 ,分别鉴定为 4 ,7 二羟基 5 甲氧基芴酮 (Ⅰ )、1,4 ,7 三羟基 5 甲氧基芴酮 (Ⅱ )、2 ,4 ,7 三羟基 4 甲氧基芴酮 (Ⅲ )、2 ,5 ,9 三羟基 4 甲氧基芴 (Ⅳ )、4 ,4′ 二羟基 3,3′ ,5 , 三甲氧基联苄 (Ⅴ )、5 ,4′ 二羟基 3,3′ 二甲氧基联苄 (Ⅵ )、3,5 ,4′ 三羟基 3′ 甲氧基联苄 (Ⅶ )、2 ,5 二羟基 4 甲氧基菲 (Ⅷ )、2 ,5 二羟基 4 甲氧基 9,10 二氢菲 (Ⅸ )、二氢麦黄酮 (Ⅹ )、柯伊利素 (Ⅺ )、高北美圣草素 (Ⅻ )、柚皮素 (ⅩⅢ )。结论 :化合物Ⅸ ,Ⅹ ,Ⅺ为首次从石斛属中分离得到 ,其它化合物均为首次从该种植物中分离得到。

云南石仙桃的化学成分及其抑制NO生成的作用

目的 研究云南石仙桃全草的化学成分,并通过测定所得化合物抑制大鼠巨噬细胞中NO的生成量,以确定云南石仙桃中抑制NO生成的活性成分.方法 采用多种柱色谱法进行分离纯化,并根据理化常数和光谱分析进行结构鉴定.利用微板紫外比色法,体外测定各化合物对脂多糖（LPS）和γ-干扰素（IFN-γ）诱导的RAW 264.7大鼠巨噬细胞NO的生成量.结果 分离得到了7个化合物,分别为反式-3,3＇,5-三羟基-2＇-甲氧基二苯乙烯（trans-3,3＇,5-trihy-droxy-2＇-methoxystilbene,Ⅰ）、顺式-3,3＇-二羟基-5-甲氧基二苯乙烯（cis-3,3＇-dihydroxy-5-methoxystilbene,Ⅱ）、反式-3,3＇,5-三羟基二苯乙烯（trans-3,3＇,5-trihydroxystilbene,Ⅲ）、3,3＇-二羟基-5-甲氧基联苄（3,3＇-dihydroxy-5-methoxybibenzyl,batatasin-Ⅲ,Ⅳ）、3,4＇-二羟基-3＇,5-二甲氧基联苄（3,4＇-dih州roxy-3＇,5-dimethoxybibenzyl,gigantol,Ⅴ）、3,3＇,5-三羟基联苄（3,3＇,5-trihydroxybibenzyl,Ⅵ）、2,7-二羟基-4-甲氧基-9,10-二氢菲（贝母兰宁,2,7-dihydroxy-4-methoxy-9,10-dihydrophenanthrene,coelonin,Ⅶ）.结论 化合物Ⅱ、Ⅳ、Ⅵ具有较强的抑制大鼠巨噬细胞NO生成的作用.化合物Ⅰ和Ⅱ为新化合物,化合物Ⅲ～Ⅶ为首次从该属植物中分离得到.

HPLC测定不同采收期球花石斛中酚类成分的含量

目的:比较不同采收期球花石斛叶酚类成分(联苄、菲和芴酮类成分)的含量变化,为球花石斛的合理采收及质量评价提供科学依据。方法:采用高效液相色潜法对不同采收期球化石斛中联苄类化合物石斛酚(gigantol)和杓唇石斛素(moscatil-in),菲类化合物 moscatin 及芴酮类化合物 dendroflorin、dengibsin 和 denchrysan A 的含量进行测定。色谱条件:色谱柱为 Beck-man Coulter ODS(250 mm×4.6 mm,5μm);流动相为乙腈和0,1%二氟醋酸水溶液,梯度洗脱[32%A(0～15 min),32%A→65%A(15～45 min),65%A→32%A(45～55 min)],流速:1.0 mL·min^(-1);检测波长280 nm;柱温25℃。结果:石斛酚、杓唇石斛素、moscatin、dendroflorin、dengibsin 和 denchrysan A 在测定的范围内均表现出良好的线性(r>0.9992);方法的回收率在95.8%～102.4%之间(RSD<2.8%)。结论:通过对同一年12个月不同采收期的球花石斛中联苄、菲和芴酮类成分的含量测定,证明方法灵敏,准确可靠,重复性好。总酚类成分的含量在4,5月份和10,11月份相对高于其他月份。

金钗石斛中联苄类和酚酸类成分的抗氧化活性研究

目的研究金钗石斛体积分数60%乙醇提取物中联苄类和酚酸类成分的抗氧化活性,探讨其抗氧化活性与结构的关系。方法综合运用现代色谱学和光谱学方法对金钗石斛体积分数60%乙醇提取物中的化学成分进行分离鉴定;采用1,1-苯基苦基苯肼(DPPH)自由基清除法和氧自由基清除能力法两种体外活性测试方法评价分得的16个化合物的抗氧化活性。结果从金钗石斛体积分数60%乙醇提取物中分离得到3个新的联苄类化合物和13个酚酸类化合物,将它们的结构鉴定为nobilinA(1),nobilinB(2),nobilinC(3),丁香酸(syringicacid)(4),2-羟基苯丙醇(2-hydroxyphenylpropanol)(5),香草醛(vanil-lin)(6),罗布麻宁(apocynin)(7),松柏醛(coniferylaldehyde)(8),丁香醛(syringaldehyde)(9),丁香乙酮(syringylethanone)(10),对羟基苯甲醛(p-hydroxybenzaldehyde)(11),3-羟基-4-甲氧基苯乙醇(3-hydroxy-4-methoxyphenylethanol)(12),α-羟基丁香丙酮(α-hydroxysyringylethanone)(13),二氢松柏醇(dihydroxyconiferylalcohol)(14),对羟基苯甲酸(p-hydroxybenzoicacid)(15),对羟基苯丙酸(p-hydroxyphenylpropionicacid)(16)。1-二苯基-2-苄基苯肼(DPPH)法活性测试中,化合物4的活性明显强于维生素C(VitC),化合物1,2,12,14显示出弱于VitC但强于2,6-二羟丁基对甲酚(BHT)的活性,化合物3和8只显示很弱的活性;氧自由基清除能力法(ORAC)法测试结果表明,化合物2～4,7～10,15显示出强于VitC的活性,化合物12,14,16活性较弱。结论金钗石斛中的联苄类和酚酸类化合物大多具有不同程度的抗氧化活性,活性的强弱与分子结构之间存在一定的相关性。

中药白及中一新的联苄化合物

目的 研究中药白及Bletillastriata (Thunb .)Reichb .f.根茎的化学成分。方法 利用硅胶柱及SephadexLH 2 0等色谱技术进行分离纯化 ,根据理化性质和光谱数据进行结构鉴定。结果 得到 3个化合物 ,分别鉴定为 5 羟基 4 (对羟基苄基 ) 3′ ,3 二甲氧基联苄 (I) ,五味子醇甲 (II) ,4,4′ 二甲氧基 2 ,2′,7,7′ 四羟基 1,1′ 联菲 (III)。结论 I为新化合物 ,II为从该植物中首次分得。