大黄酸的结构修饰及其生物活性研究进展

大黄酸是大黄素型羟基蒽醌，主要存在于大黄等中药中。大黄酸具有抗癌、抗炎、抗菌、抗阿尔茨海默病等广泛的药理活性，但由于其水溶性差、生物利用度低等缺点，限制了其临床应用。为了克服这些缺点，研究者通过对其进行结构修饰研究，设计并合成了大量生物活性更为突出的大黄酸衍生物。本文综述了近年来大黄酸的结构修饰及其生物活性研究进展，为大黄酸类衍生物的进一步研究提供参考依据。     

大黄酸及其衍生物药理作用研究新进展

摘 要：大黄酸是中药芦荟、大黄的主要成分之一,临床上用于治疗骨关节炎、糖尿病肾病等多种疾病,且具有协同抗肿瘤的作用。鉴于其较广泛的药理作用及低毒性、低成本等特点,大黄酸有望得到进一步开发与应用。综述近几年来对大黄酸及其衍生物在抗肿瘤、抗氧化、抗炎和对消化系统、肾脏、心血管系统、骨以及调脂等方面的药理作用研究进展。     

1,8-二乙酰基大黄酸-(2-溴)-乙酯的合成及对骨肉瘤MG-63细胞的作用研究

目的设计并合成新的大黄酸衍生物1,8-二乙酰基大黄酸-(2-溴)-乙酯(大黄酸衍生物B),探讨其对骨肉瘤MG-63细胞的作用和机制。方法以大黄酸为原料合成了1,8-二乙酰基大黄酸-(2-溴)-乙酯,经UV、IR、NMR确定合成产物的结构,并利用HPLC测定其纯度。采用MTT法测定大黄酸和大黄酸衍生物B对骨肉瘤MG-63细胞的体外生长抑制作用;流式细胞仪检测细胞凋亡和细胞周期分布。结果经UV、IR、~1H NMR、¹³C NMR进行分子结构表征,确证合成的目标化合物为1,8-二乙酰基大黄酸-(2-溴)-乙酯,纯度>98%。MTT结果表明,大黄酸和大黄酸衍生物B对骨肉瘤MG-63细胞的IC₅₀值分别为110.60、25.78μmol·L^-1。流式细胞仪检测细胞凋亡和周期结果表明,80μmol·L^-1的大黄酸和大黄酸衍生物B对骨肉瘤MG-63细胞的凋亡率分别为(6.87±0.53)%、(48.84±2.20)%,且主要将细胞周期阻滞在S期。结论合成化合物1,8-二乙酰基大黄酸-(2-溴)-乙酯的体外抗肿瘤活性明显优于大黄酸,且具有阻滞骨肉瘤MG-63细胞周期进程和促进其凋亡的作用。     

大黄酸及其衍生物的生物活性研究进展

大黄酸是中药大黄的主要成分之一,临床可用于治疗骨关节炎、糖尿病肾病等疾病,并且具有协同抗肿瘤的作用.本文综述了大黄酸在抗炎、抗肿瘤等方面的药理活性及作用机制,并讨论了其母核取代的衍生物、氧杂蒽醌的类似物和酯衍生物的生物活性.     

赖氨大黄酸盐的合成工艺及活性研究

目的制备水溶性大黄酸衍生物。方法以大黄酸为起始原料,制备大黄酸的赖氨酸水溶液,在30℃反应24 h,然后加入一定量丙酮使其结晶析出,得到晶体物质。根据2005年药典方法检测其在水中溶解度,用MTT法检测新化合物对细胞增殖的影响。结果目标化合物经HPLC、红外光谱和1H-NMR确证。赖氨大黄酸在水中溶解度为15 g.L？1,其在抑制肿瘤细胞和内皮细胞增殖方面与大黄酸相当。结论获得了水溶性好的大黄酸衍生物——赖氨大黄酸,并且其活性与大黄酸相当。     

赖氨大黄酸盐的合成工艺及活性研究

目的 制备水溶性大黄酸衍生物。方法 以大黄酸为起始原料,制备大黄酸的赖氨酸水溶液,在30 ℃反应24 h,然后加入一定量丙酮使其结晶析出,得到晶体物质。根据2005年药典方法检测其在水中溶解度,用MTT法检测新化合物对细胞增殖的影响。结果 目标化合物经HPLC、红外光谱和1H-NMR确证。赖氨大黄酸在水中溶解度为15 g·L^-1,其在抑制肿瘤细胞和内皮细胞增殖方面与大黄酸相当。结论 获得了水溶性好的大黄酸衍生物——赖氨大黄酸,并且其活性与大黄酸相当。     

大黄炮制品与炮制方法对其主要化学成分的影响

现代药理研究证实,大黄的主要成分是蒽醌类衍生物,含量为2%～6%,其中以结合态为主,游离态仅占一小部分[1]。游离蒽醌类衍生物(包括大黄酸、大黄素、大黄酚、大黄素甲醚等)具很强的抗菌和抗病毒作用[2];结合性葸醌类衍生物(包括双蒽酮苷及蒽醌单糖苷2类)具有泻下作用,其致泻力与所含的结合性大黄酸的含量呈正比;鞣质含量约为6%(包括没食子酰葡萄苷、大黄四聚素等),为收敛成分。大黄在我国应用历史悠久,疗效广泛,所含蒽醌等成分具有致泻、止血、抗炎及抑制癌细胞增殖和诱导凋亡等多种作用。     

浅谈大黄的炮制品及其临床配伍

现代药理研究证实,大黄主要含蒽醌类衍生物,含量约为1%～5%,其中以结合状态为主,游离状态仅占小部分。游离蒽醌类衍生物（包括大黄酸、大黄素、大黄酚、芦荟大黄素、大黄素甲醚等）具有广谱而强大的抗菌和抗病毒作用;结合性蒽醌类衍生物（包括双蒽酮苷及蒽醌单糖苷两类）具有泻下作用的化学成分,其致泻力与其中的结合性大黄酸含量成正比;鞣质含量约为5%（包括没食子酰葡萄苷、α-儿茶素、没食子酸、大黄四聚素等）为收敛成分。     

HPLC法测定牛黄解毒片中结合大黄酸的含量

<正> 蒽醌类衍生物为大黄中重要的活性成分。它们的化学结构不同或存在状态不同(游离或结合型)其药理药效差异较大。结合型大黄酸是正品大黄的主要标志之一。本文建立了结合型大黄酸的HPLC分离测定方法,为中成药的质量评价提供了方便和依据。     

大黄的炮制及有效成分分析

本文叙述了大黄的炮制方法，炮制上的大黄性状、化学成份及药理作用，炮制后的有效成分为蒽甙衍生物３．５％，游离状态的甙元，其余则为葡萄糖结合为甙，甙元主要有：大黄素、大黄酸、芦荟大黄素、大黄酚、大黄素甲醚。大黄具有杀虫作用，利胆作用，止血作用，抗感染作用，泻下作用。     

Perfusion of rat colon with sennosides, rhein and rheinanthrone. Concentration-related histamine release.

Rat colon perfused intraluminally in vitro and in vivo released histamine into the perfusates. Histamine release was increased by rhein 0.1-10 micrograms/ml and much more by rheinanthrone 0.1-10 micrograms/ml but not by sennosides A or B 1-10 micrograms/ml. The effect of rhein and rheinanthrone was reduced by tritoqualine 20 mg/kg. This raises the possibility that laxation by senna and its derivatives involves histamine formation.     

大黄酸衍生物的制备及其抗糖尿病肾病活性研究

目的 设计合成活性优化的新大黄酸衍生物,并对其进行抗糖尿病肾病活性研究。方法 以大黄酸为先导化合物合成了一系列大黄酸酰胺类衍生物;通过实时定量 PCR 实验对其进行糖尿病肾病体外筛选,并通过对糖尿病肾病模型大鼠进行药效学实验研究其降糖活性。结果 合成了11个未见文献报道的新化合物,其结构经元素分析、质谱、核磁共振谱确证。化合物 9 对四型胶原（Col Ⅳ）和胰岛素样生长因子-Ⅰ（IGF-Ⅰ）的基因表达均有下调趋势;高剂量的化合物 9 能显著降低餐后血糖水平（P < 0.001）。结论 大黄酸酰胺类衍生物在治疗糖尿病领域值得进一步研究。     

The relative purgative activities of 1,8-dihydroxyanthracene derivatives

The purgative activities of twelve different 1,8-dihydroxyanthracene derivatives including free anthraquinone, anthrone and dianthrone forms, anthraquinone O-glycosides and dianthrone O-glycosides were compared with senna pod powder using the production of wet faeces by mice as a criterion of purgation. The higher purgative activity of the dianthrone glycosides was confirmed for the compounds based on rhein. Sennidin (rhein dianthrone) was more active than had previously been reported. These highly active compounds had parallel dose response curves which were not parallel to those of the less active rhein anthrone, rhein, aloe-emodin and chrysophanol. Emodin and chrysazin were inactive in mice. The highly active compounds exerted a high activity during the initial 3 h after dosage while the less active compounds were virtually inactive during this period. Rhein anthrone appeared to act initially like the highly active primary sennosides, sennoside A and sennidin and later as the less active rhein. The results are discussed in relation to the mode of action of orally administered 1,8-dihydroxyanthracene derivatives.     

Distribution and pharmacokinetics of five Rhubarb anthraquinones in rabbits and rats

The main active components of Rhubarb are anthraquinones (AQs), most of which are glycosides and others are free. The concentrations of AQs derivatives (rhein, aloe-emodin, emodin, chrysophanol and physcion) in plasma and homogenate were assayed with a high performance liquid chromatography (HPLC) method. The pharmacokinetic parameters and distribution of Rhubarb AQs in rabbits or rats were studied after administrationof different formulas. Elimination of AQs was fit to a two-compartment model in rats and rabbits. There were no significant difference in the main pharmacokinetic parameters between rhein and AQs in rats. AQs were distributed progressively in the kidney, liver, blood, and heart. The AQs were mainly composed of rhein in vivo and was excreted by the kidney. For formulas that contained Rhubarb, rhein could be used as a probe for in vivo pharmacokinetic studies.     

Effects of senna and its active compounds rhein and rhein-anthrone on PAF formation by rat colon.

A single or a prolonged oral administration of senna (60 mg kg-1) to rats did not increase either colonic PAF (platelet activating factor) content or intraluminal release of acid phosphatase. A similar result was observed in the colonic tissue of rats perfused in-vitro with rhein (1-300 micrograms mL-1) or rhein-anthrone (1-300 micrograms mL-1). A single or prolonged administration of castor oil (2 mL) to rats increased both colonic PAF content and intraluminal release of acid phosphatase. Colonic tissue of rats perfused in-vitro with calcium ionophore A23187 (1 and 10 micrograms mL-1) formed large amounts of PAF and acid phosphatase. Since PAF can mediate intestinal damage and acid phosphatase is a marker of cellular injury, we conclude that senna and its derivatives, rhein and rhein-anthrone, are well tolerated in rats.     

In vitro deterioration of rhein anthraquinone in cecal content of rats.

The influence of the intestinal microbial reduction of rhein anthraquinone on the formation of deterioration products was studied. Therefore [14C]rhein and [14C]rhein anthrone were mixed with sterilized or non-sterilized cecal mass of rats and incubated for 20 hours at 37 degrees C. Extractions with a methanol-water (50:50) mixture or 4-nitroso-N,N-dimethylaniline (0.1%) in pyridine revealed several radioactive derivatives after TLC and autoradiography, except in the case where the anthraquinone was mixed with sterilized cecal content. Gel permeation on a styrene-divinylbenzene copolymer column of an methanol/water extract of non-sterilized cecal content incubated with [14C]rhein, showed radioactive deterioration products with a molecular weight higher than rhein anthraquinone. The high molecular weight of some deterioration products was confirmed by an ultrafiltration study where the methanol/water extract was centrifuged on a Centricon-3 microconcentrator (nominal cutoff: 3000 MW). Aqueous extracts of non-sterilized cecal content incubated with rhein were extracted with chloroform to remove rhein anthraquinone, rhein anthrone and sennidins before being intracecally injected in rats. No laxative activity was found. Furthermore it was shown that the deterioration products which are probably formed through radical reactions, no longer develop a color with a solution of KOH. Therefore it is concluded that the reduction process of dihydroxy-anthraquinones in the gut microflora followed by an extraction, accounts for the loss of anthranoid equivalents in in vivo circumstances, as several times reported in the past.     

Inducible nitric oxide synthase inhibitors of Chinese herbs III. Rheum palmatum

In this paper, the effects of bioactive compounds of Rheum palmatum L. on the inhibition of NO production from RAW 264.7 cells were explored. Seven main anthraquinone derivatives were isolated from the root of R. palmatum, and of these, emodin and rhein significantly inhibited nitrite production from lipopolysaccharide (LPS)-activated RAW 264.7 cells. The IC(50) values for inhibition of nitrite production by emodin and rhein were 60.7 and 67.3 microM, respectively. After iNOS enzyme activity was stimulated by LPS for 12 h, treatment with emodin or rhein at 20 microg/ml for 18 h did not significantly inhibit NO production. The data show that the inhibitory activity of emodin and rhein is not due to direct inhibition of iNOS enzyme activity. However, expression of iNOS and the COX-2 protein was inhibited by emodin in LPS-activated RAW 264.7 cells, and PGE(2) production was reduced. Rhein also inhibited LPS-induced iNOS protein expression, but not COX-2 or PGE(2) production. On the other hand, inhibition effects on NO production from RAW 264.7 cells were enhanced and cytotoxic effects decreased by co-treatment with emodin and rhein. In conclusion, emodin and rhein are major iNOS inhibitors of R. palmatum and may possibly serve as bioactive substances for anti-inflammation effects.     

Evaluation of the antiviral activity of anthraquinones, anthrones and anthraquinone derivatives against human cytomegalovirus.

A number of anthraquinones, anthrones and anthraquinone derivatives were evaluated for antiviral activity against human cytomegalovirus (HCMV) as well as for cytotoxicity. Of those compounds evaluated, quinalizarin, emodin, rhein, hypericin, protohypericin, alizarin, emodin bianthrone and emodin anthrone showed antiviral activity against a normal laboratory HCMV strain, AD-169. When tested against a ganciclovir-resistant strain of HCMV, the EC50 values for quinalizarin, rhein and alizarin were superior to the values obtained for the AD-169 strain of HCMV. These results suggest that these compounds will be useful as prototypes for synthesizing a class of anti-HCMV drugs that are effective against ganciclovir-sensitive and -resistant strains of HCMV.     

大黄酸在大鼠和比格犬体内的吸收动力学研究

目的：研究中药大黄的活性蒽醌单体大黄酸（rhein）在SD大鼠和Beagle犬体内的吸收动力学特征,为临床的进一步研究提供基础参数和依据。方法：采用HPLC-荧光检测法分别测定SD大鼠和Beagle犬在灌胃及静脉注射两种给药途径下单次给予不同剂量的大黄酸药物后,两种动物血浆样品中的大黄酸经时曲线过程并计算相应的药代动力学参数及绝对生物利用度。结果：SD大鼠灌胃及静脉注射高、中、低剂量大黄酸后,AUC与剂量间呈一定的线性关系（r〉0.99）,灌胃及静脉注射3个剂量下的半衰期结果相似。在上述研究范围内大黄酸在大鼠体内的药代动力学行为近似是线性的。用面积法,算得高、中、低3个剂量下大黄酸在大鼠体内的绝对生物利用度分别为16.4%、23.8%、19.4%。对6只Beagle犬进行随机交叉试验,静脉注射大黄酸真溶液（0.4mg/kg）和灌胃大黄酸混悬液（20mg/kg）,算得静注及灌胃后药物的消除半衰期分别为（1.77±0.93）、（3.25±0.80）h,Beagle犬体内的绝对生物利用度为（49.7±7.4）%。对Beagle犬组（6只）和SD大鼠灌胃3剂量组（18只）各只动物生物利用度进行方差分析,结果显示差异具有统计学意义（P〈0.01）。结论：大黄酸在不同动物间吸收存在一定的种属差异,吸收程度在Bea-gle犬体内略高于在大鼠体内。     

生熟大黄总提取物灌胃给药后游离蒽醌在SD大鼠组织中的分布差异研究

大黄应用范围广、疗效确切,然而近年来国内外实验报道大黄中蒽醌成分具有肝、肾细胞毒性。本文对比研究了生熟大黄总提取物灌胃给药后游离蒽醌在正常SD大鼠组织中的分布。肝、脾和肾组织中游离蒽醌类成分含量采用UPLC-MS/MS法测定。生熟大黄总提物(相当于生药量14.69 g.kg-1)灌胃给药,连续12周。结果表明,游离蒽醌在生大黄组大鼠组织中的分布浓度高于熟大黄组;大黄游离蒽醌在同一组织中的分布浓度顺序大致为大黄酸>大黄素>芦荟大黄素;大黄酸在肝、脾和肾组织中的分布浓度明显高于芦荟大黄素和大黄素,且大黄酸在生大黄组的组织分布浓度明显高于熟大黄组;停药恢复4周后,大黄游离蒽醌在组织中检测不到。结果提示生大黄的组织毒性可能高于熟大黄;大黄酸可能是大黄主要的毒性物质之一;大黄游离蒽醌在组织中可能无蓄积毒性。炮制过程不仅影响了有效成分的含量还可能影响其成分的组成,通过影响吸收和作用过程中成分之间的相互作用,致使生大黄组动物组织中游离蒽醌的分布浓度高于熟大黄组,这与传统中医药理论炮制减毒的思想认识基本一致。