红花桑寄生叶提取物的抗氧化活性及酚类物质分析

采用DPPH法、TEAC法、FRAP法对红花桑寄生叶不同溶剂提取物的抗氧化活性进行体外评价,并测定其总酚、总黄酮含量。结果表明,溶剂种类对红花桑寄生叶提取物的得率、总酚、总黄酮及抗氧化活性影响显著。在3种评价方法中,不同溶剂提取物的抗氧化活性均表现出不同程度的量效依赖关系。3种溶剂提取物的抗氧化活性强弱依次为丙酮提取物 >甲醇提取物 >水提取物,其中80%丙酮提取物(总酚含量最高,达276.83mg/g)抗氧化活性最强,清除DPPH自由基能力EC₅₀值为0.247,FRAP值(FeSO₄ mmol/100g)为115.81,浓度为1.0mg/ml时,TEAC值为2.04。     

益智的抗氧化作用

本文探讨了益智(Alpinia oxyphylla Miquel)超临界CO2提取物及其渣的水提物、正丙醇提取物和乙酸乙酯提取物的抗氧化作用,测定了总酚含量、黄酮含量、抗氧化力、还原能力、DPPH清除率.结果表明,益智超临界CO2提取物和正丙醇提取物的总酚含量最高,均为5.53%,乙酸乙酯提取物的总酚含量为4.04%,水提物总酚含量最低,为O.89%.抗氧化力与酚含量相关(R2=0.703).四种提取物中黄酮含量顺序为:乙酸乙酯提取物(6.29%)＞丙醇提取物(5.81%)＞水提取物(4.85%)＞超临界CO2提取物(4.70%).在还原能力、清除DPPH自由基和羟自由基方面,乙酸乙酯提取物表现出了很强的抗氧化能力,呈现剂量依赖关系.     

香露兜叶的抗氧化活性(英文)

本文评价了香露兜叶的乙醇提取物以及石油醚、乙酸乙酯、正丁醇和水相组分的抗氧化活性。在体外测定了提取物和组分的总抗氧化活性,二苯代苦味肼基(DPPH)自由基清除活性,超氧阴离子自由基清除活性和铁离子还原能力,并利用分光光度法测定了其总酚和总黄酮的含量。结果表明,所有的提取物和组分均表现出抗氧化和自由基清除活性。抗氧化活性的大小如下:正丁醇部分>乙酸乙酯部分>乙醇提取物>水部分>石油醚部分。总酚含量的顺序和其相似,说明提取物和组分中的酚类化合物使其具有抗氧化活性。香露兜叶提取物可能会成为有价值的天然抗氧化资源,并将在保健品和食品中得到应用。     

鄂西北产鱼腥草提取物体外抗氧化性的四种化学方法评价

采用α-脱氧核糖法、邻苯三酚自氧化法、DPPH法、铁氰化钾还原法等4种国内外常用的体外抗氧化活性检测方法,对鄂西北产鱼腥草石油醚提取物、无水乙醇提取物、乙酸乙酯提取物、三氯甲烷提取物的抗氧化性进行化学评价,结果表明鱼腥草提取物具有一定抗氧化性,其浓度与其抗氧化活性强弱顺序一致。     

显齿蛇葡萄提取物抗油脂氧化作用研究

用显齿蛇葡萄Ampelopsis grossedentata幼嫩茎叶提取物进行抗氧化试验,结果表明:显齿蛇葡萄幼嫩茎叶提取物有很强的抗氧化作用.0.2%的显齿蛇葡萄提取物对油脂的抗氧化效果超过同浓度的BHA及生姜提取物,0.7%的显齿蛇葡萄提取物对菜油、猪油的氧化抑制率比0.2%的BHA分别高出49.8%、9.4%,比0.2%生姜提取物分别高出46.5%、62.2%.     

皂荚棘刺提取物总黄酮提取测定、除螨活性及抗氧化活性研究

目的：对皂荚棘刺提取物的除螨及抗氧化活性进行探究。方法：检测皂荚棘刺提取物处理前后螨虫的自然死亡率和提取物的灭螨率，同时测定提取物对DPPH自由基、超氧阴离子自由基以及Fe3+的清除能力，判断皂荚棘刺提取物的除螨能力及抗氧化能力。结果：所得皂荚棘刺提取物的黄酮提取率为0.136%，其体外抗氧化实验表明皂荚皂素对DPPH自由基、超氧阴离子自由基均有明显的清除作用，且48 h除螨活性达到91%。结论：皂荚棘刺提取物具有良好的除螨活性及抗氧化活性，具有良好的应用前景。     

草菇培养物中粗三萜和黄酮含量及抗氧化抗肿瘤活性研究

采用液体摇瓶法培养草菇菌丝体,并用不同有机溶剂对培养液及菌丝体中的代谢成分分别进行分离提取,获得了不同来源的次生代谢提取物。对各提取物的成分分析表明,石油醚相、乙酸乙酯相和乙醇相提取物中均含有粗三萜和黄酮类物质,但菌丝体提取物中粗三萜和黄酮含量明显高于培养液提取物中的含量。石油醚抽提菌丝体获得的提取物中粗三萜含量最高,达17%,而乙酸乙酯抽提菌丝体获得的提取物中黄酮含量最高,达9.31%。抗氧化活性检测结果显示,石油醚相、乙酸乙酯相、乙醇相中的代谢提取物均有较高的抗氧化活性,但乙酸乙酯相提取物的抗氧化活性明显高于石油醚相提取物,具最高抗氧化活性的提取物分别来自乙酸乙酯、乙醇对菌丝体的抽提物。MTT法检测各提取物对胃癌细胞增殖的抑制作用,结果显示各组分均有较高的抗肿瘤活性,且抗肿瘤活性与提取物浓度存在明显的量效关系。     

草菇培养物中粗三萜和黄酮含量及抗氧化抗肿瘤活性研究

采用液体摇瓶法培养草菇菌丝体,并用不同有机溶剂对培养液及菌丝体中的代谢成分分别进行分离提取,获得了不同来源的次生代谢提取物。对各提取物的成分分析表明,石油醚相、乙酸乙酯相和乙醇相提取物中均含有粗三萜和黄酮类物质,但菌丝体提取物中粗三萜和黄酮含量明显高于培养液提取物中的含量。石油醚抽提菌丝体获得的提取物中粗三萜含量最高,达17%,而乙酸乙酯抽提菌丝体获得的提取物中黄酮含量最高,达9.31%。抗氧化活性检测结果显示,石油醚相、乙酸乙酯相、乙醇相中的代谢提取物均有较高的抗氧化活性,但乙酸乙酯相提取物的抗氧化活性明显高于石油醚相提取物,具最高抗氧化活性的提取物分别来自乙酸乙酯、乙醇对菌丝体的抽提物。MTT法检测各提取物对胃癌细胞增殖的抑制作用,结果显示各组分均有较高的抗肿瘤活性,且抗肿瘤活性与提取物浓度存在明显的量效关系。     

沙棘籽提取物抗氧化活性与酚类组成的研究

采用卵磷脂脂质体体系比较了沙棘籽不同溶剂提取物的抗氧化活性,对其中的抗氧化活性成分进行了分析。试验结果表明:当浓度为250μg/mL时,提取物对共轭二烯氢过氧化物的抑制率为0~90.1%,对丙二醛的抑制率为0~88.6%。70%丙酮提取物具有最强的抗氧化活性、清除DPPH自由基能力和还原力。各提取物中主要的酚类物质为原花色素,抗氧化活性与原花色素含量有很好的相关性。     

显齿蛇葡萄抗氧化活性与主要成分相关性研究

探究不同显齿蛇葡萄提取物抗氧化活性及其与多酚、黄酮、二氢杨梅素的相关性。实验分别用水和乙醇溶液提取制备四种显齿蛇葡萄提取物,并测定总多酚、总黄酮、二氢杨梅素含量。利用·OH、O_2~-·、DPPH自由基清除实验以及还原力实验共四种体系,评价各提取物抗氧化活性;使用SPSS进行活性与成分的Pearson相关分析,并建立回归方程模型。结果显示,四种提取物均具有显著抗氧化活性,但差异明显,综合以二氢杨梅素提取物最强,醇提物居中,水提物最弱。Pearson相关分析显示不同提取物的抗氧化活性与总多酚、总黄酮、二氢杨梅素含量呈显著正相关(P 0.01),表明总多酚、总黄酮、二氢杨梅素均是显齿蛇葡萄中主要抗氧化功效因子,但不同抗氧化体系中三种成分的影响程度表现各异。     

中药紫草的化学成分和药理学研究进展

本文对中药紫草(Arnebia euchroma(Royle)Johnst.,Lithospermum erythrorhizon Sieb.et Zucc.和A.guttata Bunge的干燥根)的化学成分和药理作用的研究进展进行了综述.     

紫草的制剂学研究进展

本文对国内有关紫草制剂的研究概况进行了综述,为研究和开发紫草制剂提供依据.     

Brazilin and the extract from Caesalpinia sappan L. protect oxidative injury through the expression of heme oxygenase-1

In this study, we examined the protective effects of Caesalpinia sappan L. and its major component, brazilin, against tert-butylhydroperoxide (t-BHP)-induced cell death in House Ear Institute-Organ of Corti 1 (HEI-OC1) cells. We found that the extract of C. sappan L. and brazilin induced antioxidant response element (ARE)-luciferase activity and heme oxygenase-1 (HO-1) expression in a concentration-dependent manner. The inductive effect of brazilin was more potent than the extract of C. sappan L. and the expression of HO-1 reached a peak at 12 h after brazilin treatment. The extract and brazilin protected the cells against t-BHP-induced cell death. Their protective effects were abrogated by zinc protoporphyrin IX (ZnPP IX), a HO inhibitor. These results demonstrate that the extract of C. sappan L. and brazilin induce the expression of HO-1 and the enzyme diminishes t-BHP-induced cell death in HEI-OC1 cells.     

Caffeic acid oligomers in Lithospermum erythrorhizon cell suspension cultures

Lithospermum erythrorhizon cells cultured in pigment production (M-9) medium produced lithospermic acid B, a dimerized caffeic acid ester derivative, in quantities similar to the production of shikonin. The cells also produced a related dimer, (+)-rabdosiin. In Linsmaier-Skoog liquid medium, which suppresses shikonin production, both lithospermic acid B and (+)-rabdosiin were still formed. Lithospermic acid, a caffeic acid-rosmarinic acid conjugate, was isolated as a main constituent in Lithospermum hairy root cultures. In the aerial parts of L. erythrorhizon, the content of these phenylpropanoid oligomers was relatively low compared to that of rosmarinic acid.     

Human ACAT inhibitory effects of shikonin derivatives from Lithospermum erythrorhizon

Three naphthoquinones were isolated by bioassay-guided fractionation from the CHCl(3) extracts of roots of Lithospermum erythrorhizon. They were identified as acetylshikonin (1), isobutyrylshikonin (2), and beta-hydroxyisovalerylshikonin (3) on the basis of their spectroscopic analyses. The compounds 1-3 were tested for their inhibitory activities against human ACAT-1 (hACAT-1) or human ACAT-2 (hACAT-2). Compound 2 preferentially inhibited hACAT-2 (IC(50)=57.5microM) than hACAT-1 (32% at 120microM), whereas compounds 1 and 3 showed weak inhibitory activities in both hACAT-1 and -2. To develop more potent hACAT inhibitor, shikonin derivatives (5-11) were synthesized by semi-synthesis of shikonin (4), which was prepared by hydrolysis of 1-3. Among them, compounds 5 and 7 exhibited the strong inhibitory activities against hACAT-1 and -2. Furthermore, we demonstrated that compound 7 behaved as a potent ACAT inhibitor in not only in vitro assay system but also cell-based assay system.     

High level expression of chorismate pyruvate-lyase (UbiC) and HMG-CoA reductase in hairy root cultures of Lithospermum erythrorhizon

Shikonin, a red naphthoquinone pigment, is produced by cell cultures of Lithospermum erythrorhizon (Boraginaceae). It is biosynthetically derived from two key precursors, 4-hydroxybenzoate (4HB) and geranyldiphosphate (GPP). The bacterial ubiC gene, encoding chorismate pyruvate-lyase (CPL) which converts chorismate to 4-hydroxybenzoate, was expressed in L. erythrorhizon under the control of the strong (ocs)(3)mas-promoter. This introduced an efficient biosynthetic pathway to 4HB, i.e. a one-step reaction from chorismate, in addition to the endogeneous multi-step phenylpropanoid pathway. Feeding experiments with [1,7-(13)C(2)]shikimic acid showed that in the most active transgenic line, 73% of 4HB was synthesized via the genetically introduced pathway. However, there was no correlation between CPL activity and 4HB glucoside or shikonin accumulation in the transgenic lines. HMG-CoA reductase (HMGR) is involved in the biosynthesis of GPP in L. erythrorhizon. Two forms of HMGR1 of Arabidopsis thaliana were expressed in Lithospermum under control of the (ocs)(3)mas promoter. Only moderate increases in enzyme activity were obtained with the complete enzyme, but high activity was achieved using the soluble cytosolic domain of HMGR1. Shikonin accumulation remained unchanged even upon high expression of soluble HMGR.     

A novel dark-inducible protein, LeDI-2, and its involvement in root-specific secondary metabolism in Lithospermum erythrorhizon

Lithospermum erythrorhizon produces red naphthoquinone pigments that are shikonin derivatives. They are accumulated exclusively in the roots of this plant. The biosynthesis of shikonin is strongly inhibited by light, even though other environmental conditions are optimized. Thus, L. erythrorhizon dark-inducible genes (LeDIs) were isolated to investigate the regulatory mechanism of shikonin biosynthesis. LeDI-2, showing the strict dark-specific expression, was further characterized by use of cell suspension cultures and hairy root cultures as model systems. Its mRNA accumulation showed a similar pattern with that of shikonin. In the intact plants LeDI-2 expression was observed solely in the root, and the longitudinal distribution of its mRNA was also in accordance to that of shikonin. LeDI-2 encoded a very hydrophobic polypeptide of 114 amino acids that shared significant similarities with some root-specific polypeptides such as ZRP3 (maize) and RcC3 (rice). Reduction of LeDI-2 expression by its antisense DNA in hairy roots of L. erythrorhizon decreased the shikonin accumulation, whereas other biosynthetic enzymes, e.g. p-hydroxybenzoic acid:geranyltransferase, which catalyzed a critical biosynthetic step, showed similar activity as the wild-type clone. This is the first report of the gene that is involved in production of secondary metabolites without affecting biosynthetic enzyme activities.     

Glucosylation of esculetin by plant cell suspension cultures

Cell suspension cultures of Lithospermum erythrorhizon, Gardenia jasminoides and Nicotiana tabacum were capable of glucosylating esculetin to esculin (7-hydroxycoumarin-6-O-β-D-glucoside). Especially, a culture strain of Lithospermum erythrorhizon was superior in the esculetin glucosylating capability; 40 to 50% of esculetin administered to the culture medium at early stationary growth stage was converted into esculin within 24 h. The rate of glucosylation was also dependent on the growth stage and the medium composition especially growth hormones and sugar.     

硬紫草细胞悬浮培养和紫草宁及其衍生物的形成

硬紫草细胞悬浮培养形成紫草宁及其衍生物时．细胞生长曲线呈扁平的s形。细胞停止生长后,紫草宁及其衍生物大量形成,二者的动态变化呈负相关。测定丁此过程中培养液的无机元素和可溶性糖含量、溶氧、pH值以及细胞形态的变化情况,可作为硬紫草细胞大规模培养的参考。