Nine New Sesquiterpenes from Dendrobium nobile

Nine new sesquiterpenes, i.e., dendronobilins A–I ( 1 – 9 ), with copacamphane‐type ( 1 ), picrotoxane‐type ( 2 – 6 ), muurolene‐type ( 7 ), alloaromadendrane‐type ( 8 ), and cyclocopacamphane‐type ( 9 ) skeletons, were isolated from the 60% EtOH extract of the stems of Dendrobium nobile. Their structures were established as (1R,2R,4S,5S,6S,8S,9R)‐2,8‐dihydroxycopacamphan‐15‐one ( 1 ), (2β,3β,4β,5β)‐2,4,11‐trihydroxypicrotoxano‐3(15)‐lactone ( 2 ), (2β,3β,5β,9α,11β)‐2,11‐epoxy‐9,11,13‐trihydroxypicrotoxano‐3(15)‐lactone ( 3 ), (2β,3β,5β,12R*)‐2,11,13‐trihydroxypicrotoxano‐3(15)‐lactone ( 4 ), (2β,3β,5β,12S*)‐2,11,13‐trihydroxypicrotoxano‐3(15)‐lactone ( 5 ), (2β,3β,5β,9α)‐9,10‐cyclo‐2,11,13‐trihydroxypicrotoxano‐3(15)‐lactone ( 6 ), (9β,10α)‐muurol‐4‐ene‐9,10,11‐triol ( 7 ), (10α)‐alloaromadendrane‐10,12,14‐triol ( 8 ), and (5β)‐cyclocopacamphane‐5,12,15‐triol ( 9 ) on the basis of spectroscopic analysis. The absolute configuration of compound 1 was tentatively assigned as (1R,2R,4S,5S,6S,8S,9R) according to its CD spectrum and the octant rule. Compounds 1 and 4 – 9 were inactive in our preliminary in vitro immunomodulatory bioassay.     

红外光谱结合化学计量学快速预测铁皮石斛中总黄酮含量

评价药用植物质量的主要手段之一是有效成分含量检测,不同采收期对药用植物有效成分含量有明显影响。通过傅里叶变换红外光谱(FTIR)结合化学计量学建立快速预测不同采收期铁皮石斛中总黄酮含量的方法,以期为铁皮石斛质量快速预测评价提供研究基础。采收2014年1至12月的铁皮石斛样品干燥粉碎;以氯化铝显色法测定铁皮石斛中总黄酮含量,分析不同采收时间铁皮石斛总黄酮的累积规律;采集样品红外光谱信息,归属红外吸收峰,拟合红外光谱数据和总黄酮含量数据,结合一阶导数、二阶导数、多元散射校正、标准正态变量、正交信号校正等对数据进行预处理,建立偏最小二乘回归模型预测样品中总黄酮含量。结果显示：(1)样品和标准品芦丁均在270 nm附近有共有吸收峰,实验以270 nm为总黄酮定量波长,标准曲线为y=6.076 5x+0.055 8,相关系数r=0.996 6,线性关系良好;重现性、精密度和稳定性相对标准偏差分别为1.00%,0.37%和0.28%,该方法稳定可靠;(2)总黄酮含量随时间变化趋势为先升高后降低,6月-8月样品含量较高,平均含量大于64.10 mg·g-1;(3)铁皮石斛红外光谱数据与总黄酮含量拟合后进行一阶导数、二阶导数、多元散射校正、标准正态变量、正交信号校正等组合处理,用PLSR模型预测铁皮石斛的总黄酮含量,结果最佳预处理方式为2D+SG5+SNV+OSC-PLSR,训练集和验证集r分别为0.979 0和0.882 4,验证均方根误差(RMSEE)和预测均方根误差(RMSEP)分别为2.438 2和4.169 9,铁皮石斛中总黄酮含量预测值与测量值较接近,表明PLS模型可用于总黄酮含量的快速预测。傅里叶变换红外光谱结合化学计量学能实现铁皮石斛中总黄酮含量准确预测,为铁皮石斛质量评价提供快速、有效的方法。     

不同石斛枫斗中酚酸类活性成分的比较及杓唇石斛素和石斛酚含量的测定

建立了基于液相色谱-离子阱飞行时间串联质谱(LC-IT-TOF MS/MS)的酚酸类分析方法,对6种共18批次的石斛枫斗药材中的酚类化合物进行了研究,其中18种酚酸类化合物得到初步定性。在共有化合物中选择杓唇石斛素和石斛酚作为质量控制的目标化合物。在此基础上,采用响应面法(RSM)确定了提取溶剂为60%甲醇、提取时间为65 min的超声提取杓唇石斛素和石斛酚的最佳条件,建立了石斛枫斗中杓唇石斛素、石斛酚的高效液相色谱(HPLC)含量测定方法。定量线性优于0.999 8,检出限(LOD)分别为0.18 mg/L和0.09 mg/L,重复性的相对标准偏差(RSD)小于3%,加标回收率均值分别为97.1%和101.4%。这些结果表明本研究建立的方法可用于石斛枫斗药材中酚酸类化学成分研究及质量控制。     

金钗石斛免疫活性多糖DNP-W1B的结构特征

从金钗石斛茎中获得了1个均一多糖组分DNP-W1B, 采用化学与光谱学结合的手段对其一级结构进行了解析. 结果表明, DNP-W1B分子量为7.7×10⁵, 比旋度²⁰_D=+81.3°(c0.3, H₂O), 由葡萄糖、 阿拉伯糖和半乳糖3种单糖组成, 摩尔比为6.2:3.1:0.9. DNP-W1B主链由1,4-和1,6-连接的葡萄糖残基组成, 在主链1,6-连接葡萄糖残基的4位形成分支, 支链由末端半乳糖残基和阿拉伯糖残基组成. 初步的免疫活性实验结果表明, DNP-W1B在体外能促进免疫细胞的增殖.     

秋水仙素诱导铁皮石斛多倍体研究

用不同质量分数秋水仙素处理铁皮石斛种胚原球茎诱导多倍体,结果表明：1.秋水仙素对种胚原球茎的生长有不同程度的抑制作用,对根系生长的抑制尤为明显.2.由于种胚原球茎完整性好,耐受性强,要获得多倍体则需较高质量分数的秋水仙素或较长的处理时间.3.本实验诱导多倍体有相当一部分是非整倍体,通过流式细胞检测到的变异率高于形态学观察的结果.4.经秋水仙素处理后,有些植株的茎变得粗短,出现茎分叉现象,叶片形状呈锯齿状,变小变厚等变异特征.     

优化Rpa电压-电感耦合等离子体质谱法测定铁皮石斛中不同部位的14种金属元素

建立了优化Rpa电压-电感耦合等离子体质谱法测定铁皮石斛中不同部位的Mg、Al、K、Ca、Cr、Mn、Fe、Cu、Zn、Ni、As、Se、Cd和Pb 14种金属元素的方法。样品经微波消解后,采用动态反应池去除样品基体带来的质谱干扰,同时针对部分高含量元素的信号溢出问题,实验优化了Rpa电压,免去了样品的二次稀释。各元素的检出限为0.02~32μg/L,日内精密度(RSD,n=6)和日间精密度(RSD,n=12)分别在0.7%~4.6%和1.5%~5.8%之间;样品的加标回收率为83.9%~112%。采用该方法对柑橘叶标准样品(GBW10020)进行了验证,测定值均在参考值范围内。方法对大棚种植的铁皮石斛的不同部位样品进行了测定,发现重金属含量处于较低水平,其中叶和花的重金属含量要显著高于茎中的含量。     

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 method for isolating functional RNA from callus of Dendrobium candidum contented rich polysaccharides

Isolation of high-quality RNA from Dendrobium candidum is particularly difficult. D. candidum contains considerable amounts of polysaccharides that coprecipitate with RNA, which render RNA unsuitable for either cDNA synthesis and/or PCR amplification. In this paper, a rapid and efficient method was described for functional RNA isolation from the callus of D. candidum. The procedure included: (i) an extraction with phenol and isopropyl alcohol, to remove proteins and polyphenols; (ii) purifications by lithium chloride, pre-cooled (−20 °C) ethanol successively to remove polysaccharides. The method resulted in high-quality RNA suitable for DDRT-PCR and cDNA library analysis finally.     

A new furostanol saponin from Dendrobium chrysanthum Lindl. with cytotoxic activity

A new furostanol saponin, (25R)-26-O-(α-d-glucopyranosyl)-(1→2)-α-l-rhamnopyranosyl-furost-5-ene-3β, 22α, 26-triol-3-O-α-d-glucopyranoside (1), together with four known compounds 2–5 were isolated from the ethanolic extract of the stems of Dendrobium chrysanthum Lindl. The structures of these new compounds were identified by extensive spectroscopic analysis including 1D and 2D NMR and HR-ESI-MS, as well as chemical methods. Compounds 1–3 were isolated from D. chrysanthum for the first time. Furthermore, the inhibitory effects of the compounds on tumor cells were evaluated, and compounds 1–2 exhibited significant cytotoxic activities potentially against SPC-A1, MCF-7 and HeLa human cancer cell lines. Compounds 3–5 showed inhibitory activity against the SPC-A1 and MCF-7.