Tautomeric and conformational isomerism of natural hydroxyanthraquinones

Natural 1,5-di-, 1,4,5-tri-, and 1,4,5,8-tetrahydroxyanthraquinones and their anions and metal complexes were shown to be equilibrium mixtures of tautomers and conformers using quantum-chemical and correlation analysis of elecronic absorption spectra. Solvent effects, ionization, complexation, and the introduction and substitution of substituents were accompanied by shifts of tautomeric and conformational equilibria that determine the color of the compounds. __________ Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 224–229, May–June, 2006.     

UPLC‐ESI/MS determination of 17 active constituents in two categorized formulas of traditional Chinese medicine,Sanhuang Xiexin Tang and Fuzi Xiexin Tang: application in comparing the differences in decoctions and macerations

A rapid and sensitive UPLC‐ESI/MS method was established and validated to determine 17 active constituents (aconitine, hypaconitine, mesaconitine, benzoylaconine, benzoylhypaconine, benzoylmesaconine, berberine, palmatine, jatrorrhizine, coptisine, baicalein, wogonin, baicalin, wogonoside, emodin, aloe‐emodin and rhein) in Sanhuang Xiexin Tang (SXT) and Fuzi Xiexin Tang (FXT), which are two classic compound recipes from Xiexin Tang categorized formulas in traditional Chinese medicien. The separation was performed on a UPLC BEH C₁₈ column gradient eluted using acetonitrile and 0.1% formic acid as mobile phase. ESI/MS was operated in positive ([M + H]⁺) in selected ion recording mode for analysis of alkaloids and flavones, while in negative ([M ? H]^?) selected ion recording mode for anthraquinones. All of the 17 constituents exhibited good linearity in a relatively wide concentration ranges with the lowest limits of detection of 0.38 ng/mL. All of the relative standard deviation values of intra‐ and inter‐precisions and stabilities of 17 constituents were within 5%. The method was successfully applied to determine 17 active constituents in decoctions and macerations of SXT and FXT. The results indicated that different preparative methods resulted in significant diversity in concentrations of the 17 analytes. Herb–herb interaction appeared between aconitum alkaloids in Aconiti Lateralis Radix Preparata and another three herbs. Copyright © 2013 John Wiley & Sons, Ltd.     

基于反相高效液相色谱法构建 QSRR 模型测定萘类及蒽醌类化合物的正辛醇-水分配系数

正辛醇-水分配系数(Kow )是评价药物毒性、活性及跨膜转运等的重要参数,但直接测定法实验过程复杂。本研究采用反相高效液相色谱(RP-HPLC)法,以甲醇-水为流动相,以29种已知 Kow的酸性和中性苯系物及萘类、醌类衍生物为模型化合物,以保留时间两点校正法( DP-RTC)校正保留时间,并由 Snyder-Soczewinski方程得100%水相保留因子(kw ),建立了表观正辛醇-水分配系数 Kow＂与 kw 的定量关系(Quantita-tive structure-retention relationship, QSRR)模型,并对模型进行了内、外部验证。结果表明,不同 pH 下的 QSRR模型线性相关性 R2=0.974~0.976,内部验证( R2cv =0.970~0.973)和外部验证结果(6种验证化合物,1.4%≤相对误差(RE)≤7.9%)令人满意,与考虑了分子结构参数后建立的线性溶剂化能模型(LSER)相比无差异。将建立的 QSRR 模型应用于11种萘类和蒽醌类化合物的 Kow测定,并与软件计算值、摇瓶法实验值比较,结果表明,本方法准确性更高,且简单快捷,可用于快速准确预测复杂混合物体系中组分的 Kow。     

大黄游离羟基蒽醌的TG—DTA和XRD谱图特征分析

中药大黄属蓼科植物,性寒味苦,是中医临床常用药物,具有攻坚破积、活血化瘀、泻火凉血、清热解毒及抗菌、抗炎、调节免疫、抗肿瘤、止血和保健等作用[1].     

Tectona grandis (teak) – A review on its phytochemical and therapeutic potential

Tectona grandis Linn (Teak), is locally known as Sagwan, belongs to Lamiaceae family. It is one of the most valuable timber in the world, due to its beautiful surface and its resistance to termite and fungal damage. The main active ingredient compounds that are responsible for these action are tectoquinone, lapachol and deoxylapachol. Naphthoquinones, anthraquinones and isoprenoid quinones are abundant metabolites in teak. In addition to these, teak contains several other phytochemicals such as triterpenoids, steroids, lignans, fatty esters and phenolic compounds. Pharmacologically, the plant has been investigated for antioxidant, anti-inflammatory, anti-pyretic, cytotoxic, analgesic, hypoglycemic, wound healing and antiplasmodial activities. The present review highlights the phytochemical and pharmacological aspects of teak.     

Screening for novel plant sources of prenyloxyanthraquinones: Senna alexandrina Mill. and Aloe vera (L.) Burm. F.

As a continuation of our ongoing studies aimed to reveal the presence of oxyprenylated anthraquinones in plants claimed to have a laxative effect, in this article, we describe the extraction and HPLC separation of madagascin (3-isopentenyloxyemodin) and 3-geranyloxyemodine from dried leaves and fruits of Senna alexandrina Mill. (Leguminosae) and leaves and gel of Aloe vera (L.) Burm. F. (Xanthorrhoeaceae). Both compounds are described herein for the first time as components of extracts of the title plants.     

Electrochemical properties of modified carbon paste electrodes containing some amino derivatives of 9,10-anthraquinone

The preparation and aqueous electrochemistry of carbon paste electrodes modified by some amino-substituted 9,10-anthraquinones are reported. In all cases, the reduction processes studied by cyclic voltammetry reveal a quasi-reversible behavior. The half-wave potentials were calculated as a function of the solution pH and from the resulting potential-pH plots the formal potentials and pK _a ^′ values of different redox and acid-base couples involved at various pH ranges were evaluated. The diffusion coefficients of different anthraquinone derivatives used in paraffin oil were calculated by chronoamperometry. Received: 3 May 1999 / Accepted: 15 November 1999     

Practical Synthesis of p‐ and o‐Amino‐ and Methoxyphenolic Anthraquinones

New versatile and selective methods for the syntheses of substituted amino‐ and methoxyphenolic anthraquinones ( I–IV ) based on fusion of cyanophthalides ( V ) and semiquinone aminals ( VI , VII ) under basic conditions are described.