The direct release of nitric oxide by gypenosides derived from the herb Gynostemma pentaphyllum.

Herbal medicines are increasingly being utilized to treat a wide variety of disease processes. Gypenosides are triterpenoid saponins contained in an extract from Gynostemma pentaphyllum and are reported to be effective in the treatment of cardiovascular diseases; however, the mechanism underlying the therapeutic effect is not known. We tested the hypothesis that gypenosides extracted from G. pentaphyllum elicit vasorelaxation through the direct release of endothelium-derived nitric oxide. Nitric oxide production in bovine aortic endothelial cells grown under standard tissue culture conditions was quantitated using a chemiluminescence method. Arterial vasomotion was assayed using isolated porcine coronary artery rings under standard isometric recording conditions. The extract of G. pentaphyllum at 0.1-100 microg/ml elicited concentration-dependent vasorelaxation of porcine coronary rings that was antagonized by the nitric oxide synthase inhibitor N(G)-nitro-l-arginine methyl ester. Indomethacin had no significant effect on G. pentaphyllum-induced relaxation. The G. pentaphyllum extract elicited a concentration-dependent increase in nitric oxide production from cultured bovine aortic endothelial cells. At the concentrations utilized, there was no morphological evidence for cellular toxicity. These results demonstrate that extracts of G. pentaphyllum directly stimulate nitric oxide release, but not prostanoid production. Nitric oxide production in response to gypenosides may be one mechanism whereby this herbal medicine elicits its therapeutic effects.     

温度对绞股蓝和五柱绞股蓝生长及总皂苷积累的影响

温度是影响绞股蓝生长发育和总皂苷积累的重要环境因子之一。将绞股蓝和五柱绞股蓝幼苗置于10、15、20、25℃和30℃的光照培养箱中处理40d,检测其形态指标和总皂苷含量。结果表明:在25℃条件下,绞股蓝的叶面积、叶柄长、茎长、新萌叶片数、生物量和总叶绿素含量均为最高,五柱绞股蓝的生长发育也具有类似的规律,因此推断25℃是绞股蓝和五柱绞股蓝生长发育的适温条件。绞股蓝和五柱绞股蓝的总皂苷含量则以30℃下最高。绞股蓝的生物量和总皂苷含量决定了总皂苷产量,25～30℃最有利于提高绞股蓝的总皂苷产量,30℃则是提高五柱绞股蓝总皂苷产量的最适温度。     

动态连续逆流提取绞股蓝皂苷的研究

本文在中试条件下,通过单因素试验和正交试验考察不同因素对绞股蓝皂苷提取得率的影响,从而探讨动态连续逆流提取绞股蓝皂苷的最佳工艺。结果表明:动态连续逆流提取绞股蓝皂苷最佳条件为:提取溶剂温度为80℃,料液比为1∶35(g/mL),提取时间为50 min。在此条件下,绞股蓝提取物平均提取得率为33.95%,皂苷得率为8.9%;动态连续逆流提取绞股蓝皂苷具有生产连续性好、皂苷提取得率高、产品纯度高等优点。     

Dammarane-type saponins from Gynostemma pentaphyllum

Seven dammarane glycosides, gypenosides GC1 to GC7, together with ten known compounds, gypenosides V, XIV, XLII-XLVI, gynosaponins TN-1, -2, and gymnemaside VI, were isolated from the methanol extract of the aerial parts of Gynostemma pentaphyllum. Their structures were elucidated by both analysis of 1D and 2D NMR spectra and chemical degradation.     

绞股蓝总皂甙含量与其营养器官和生长期相关性的研究

应用组织化学和植物化学方法,研究绞股蓝总皂甙含量与其营养器官和生长期的相关性。结果表明,不同营养器官中绞股蓝总皂甙含量叶最高,茎次之,根茎和根最低。绞股蓝地上部分总皂甙含量从营养生长→开花→结果不同生长期呈现由低→高→低的变化趋势,其中7、8、9月的开花期绞股蓝总皂甙含量达到顶峰,为药材最佳采收时间。研究还得出,绞股蓝叶的形态结构特征与其总皂甙含量相关,可作为选育绞股蓝优良品种的指标。     

连续逆流提取机及其在绞股蓝皂苷提取工艺中的应用

简述了中草药连续逆流提取机的基本结构和工作原理.以水为溶媒、绞股蓝为原料,进行绞股蓝有效成分的提取试验.以绞股蓝水溶出物和总皂苷为目标物,考察提取温度、液料比和提取时间等因素对提取得率的影响,并通过L9(33)正交实验设计,对提取工艺进行优选.采用中草药连续逆流提取机提取绞股蓝有效成分的最佳工艺条件:提取溶剂温度80 ℃,料液比1:35(g/mL),提取时间50 min;所得提取物得率为33.95%,总皂苷得率为8.9%.     

绞股蓝龙须茶的人参皂甙组织定位及皂甙含量的季节变化

应用组织化学定位技术及植物化学方法,研究了人参皂甙在商品绞股蓝龙须茶中的组织分布状态及绞股蓝总皂甙在不同季节中的含量变化。结果表明,绞股蓝内的人参皂甙遇特定的显色剂出现深浅不同的红色,色度与人参皂甙含量呈正相关。绞股蓝叶内的人参皂甙主要分布在叶肉组织,茎内的人参皂甙主要分布于维管束的韧皮部薄壁细胞中,同化组织、厚角组织和表皮也有少量分布．木质部和髓薄壁组织中无皂甙分布。在4月至11月的龙须茶采收期中,总皂甙含量呈逐渐上升的势态,4月最低．9月最高,含量变化与月总降雨量呈显著的正相关。研究认为在8月后湿润凉爽气候条件下采摘绞股蓝芽尖加工而成的龙须茶品质最好。     

绞股蓝营养器官中皂苷积累组织的超微结构观察

应用超薄切片和电镜技术观察了绞股蓝营养器官中积累皂苷的叶肉细胞、茎表皮细胞、茎皮层细胞和茎韧皮部细胞的超微结构.结果表明,幼叶叶肉细胞的液泡中具有蛋白体性质的电子致密物;随着叶的发育,叶绿体结构逐渐完善并积累淀粉粒;地上茎表皮细胞的外侧壁增厚,皮层细胞含叶绿体,液泡内有团块状结构;根状茎中的筛管细胞具有囊泡结构,其内的颗粒状内含物可释放至液泡和跨壁运输;韧皮薄壁细胞近细胞壁处具有丰富的细胞质和细胞器.但上述细胞中均未发现与皂苷积累相关的特殊电子致密物.     

绞股蓝的皂甙成份及资源

本文综述了绞股蓝植物资源。皂甙含量和84种绞股蓝皂甙的化学结构及其水解转化的意义。     

绞股蓝的抗肿瘤作用

本文综述了绞股蓝的抗肿瘤作用及具有抗肿瘤活性的绞股蓝皂甙的结构特点、作用机理、构效关系和这种抗肿瘤新药的研究进展。     

绞股蓝营养器官各发育阶段结构与总皂甙含量相关性的研究

应用组织化学定位技术及植物化学方法,研究了不同发育阶段绞股蓝茎叶的结构与其中人参皂甙分布积累和总皂甙含量的关系。绞股蓝内的人参皂甙通过特定的显色剂能显示从紫红到浅红的颜色反应,颜色深浅与人参皂甙含量呈正相关。结果表明,叶内的皂甙主要分布在叶肉组织内,未分化的叶肉组织比成熟组织含量高,衰老的叶片不含皂甙。茎内的皂甙主要分布于维管束的外生韧皮部薄壁细胞中,表皮、同化组织、厚角组织及周皮的栓内层也有少量分布,木质部和髓薄壁组织无皂甙积累;幼茎所含总皂甙高于发育成熟的茎和老茎,含量最高的则是具有贮藏功能的根状茎。在绞股蓝全草中,叶的总皂甙含量高于相应发育阶段的茎,而以当年生根状茎的含量最高。提出了皂甙在叶内积累、茎内运输和地下茎内贮藏的观点及科学采收绞股蓝的建议。     

不同前处理方式绞股蓝总皂甙含量的差异

用超声法提取绞股蓝鲜叶样、杀青样、烘干样、风干样以及绞股蓝袋泡茶干茶样的总皂甙,并测定其含量。结果表明,总皂甙含量为杀青样> 烘干样> 鲜叶样> 风干样> 干茶样,可能由于各处理的糖苷酶失活程度不同导致皂甙不同程度的分解,在生产和实验研究中应引起注意。     

绞股蓝皂苷-硒配合物对酪氨酸酶的活性影响及动力学分析

为考察绞股蓝皂苷及其硒配合物对酪氨酸酶的动力学参数和作用机理。本研究采用体外酶促反应,以L-酪氨酸和L-DOPA为底物,模拟了酪氨酸酶单酚和二酚酶的体外催化氧化过程。绞股蓝总皂苷在50%、70%乙醇洗脱段和50%、70%乙醇洗脱绞股蓝皂苷-硒配合物在酪氨酸酶上的Ki值分别为1. 533、1. 767、1. 312和1. 210 mmol/L。Ki值越低,对酪氨酸酶的抑制作用越强,单酚酶的氧化阶段越快,表明硒元素显著提高了绞股蓝皂苷对酪氨酸酶的抑制作用。酶反应动力学分析表明,四种绞股蓝皂苷及其硒配合物对酪氨酸的抑制作用均为混合竞争抑制。其独特的药理化学特性为绞股蓝及硒系美白化妆品的进一步研究开发提供了理论依据和参考。     

Heat-processed Gynostemma pentaphyllum extract improves obesity in ob/ob mice by activating AMP-activated protein kinase

Gynostemma pentaphyllum is widely used in Asian countries as a herbal medicine to treat dyslipidemia, type 2 diabetes and inflammation. An ethanol extract of G. pentaphyllum lessened obesity by activating AMP-activated protein kinase (AMPK). The levels of damulins A and B, components responsible for AMPK activation in the extract, were increased by autoclaving in a time-dependent manner. Heat-processed G. pentaphyllum extract, actiponin containing damulins A (0.93?%, w/w) and B (0.68?%, w/w), significantly stimulated fat oxidation and glucose uptake via AMPK activation in L6 myotube cells. Oral administration of actiponin to ob/ob mice for 8?weeks decreased body weight gain, liver weight, and blood cholesterol levels with AMPK activation in the soleus muscle. Our results demonstrate the beneficial effect of G. pentaphyllum on improving obesity and have elucidated the underlying molecular mechanisms.     

绞股蓝人参皂甙的组织化学定位及其含量的变化

应用光镜技术、组织化学定位及植物化学方法,研究了人参皂甙在绞股蓝营养器官中的积累分布状态以及不同生长期、不同器官、不同性别之间的绞股蓝总皂甙含量的动态变化。结果表明,绞股蓝人参皂甙主要分布在营养器官的同化组织及韧皮部薄壁细胞中,厚角组织、表皮及周皮的栓内层也有少量分布,木质部和髓薄壁组织中无皂甙分布;叶中皂甙积累最多,茎次之,根最少。绞股蓝在营养生长期→花果期→枯萎期的生长发育过程中,其地上部分的皂甙含量呈现出低→高→低的变化趋势;叶的含量高于茎,雄株的含量高于雌株。从而认为在9—10月的花果期采收绞股蓝的地上部分而保留地下茎和根,有利于药材品质和产量的提高,又有利于药用资源的可持续开发利用。     

绞股蓝人参皂甙的组织化学定位及其含量的变化

应用光镜技术、组织化学定位及植物化学方法,研究了人参皂甙在绞股蓝营养器官中的积累分布状态以及不同生长期、不同器官、不同性别之间的绞股蓝总皂甙含量的动态变化。结果表明,绞股蓝人参皂甙主要分布在营养器官的同化组织及韧皮部薄壁细胞中,厚角组织、表皮及周皮的栓内层也有少量分布,木质部和髓薄壁组织中无皂甙分布;叶中皂甙积累最多,茎次之,根最少。绞股蓝在营养生长期→花果期→枯萎期的生长发育过程中,其地上部分的皂甙含量呈现出低→高→低的变化趋势;叶的含量高于茎,雄株的含量高于雌株。从而认为在9-10月的花果期采收绞股蓝的地上部分而保留地下茎和根,有利于药材品质和产量的提高,又有利于药用资源的可持续开发利用。     

Recognition of formamidopyrimidine by Escherichia coli and mammalian thymine glycol glycosylases. Distinctive paired base effects and biological and mechanistic implications

The activity of prokaryotic and mammalian thymine glycol (Tg) glycosylases including Escherichia coli endonuclease III (Endo III) and endonuclease VIII (Endo VIII) and mouse Endo III homologue (mNth1) for formamidopyrimidine (Fapy) has been investigated using defined oligonucleotide substrates. 2, 6-Diamino-4-hydroxy-5-N-methylformamidopyrimidine, a methylated Fapy derived from guanine, was site specifically incorporated in the oligonucleotide. The substrates containing Fapy:N pairs (N = A, G, C, T) as well as a Tg:A pair, a physiological substrate of Endo III, Endo VIII, and mNth1, were treated by the enzymes and nicked products were quantified by gel electrophoresis. The activity of Endo III and Endo VIII for Fapy varied markedly depending on the paired base, being the highest with G (activity relative to Tg = 0. 55 (Endo III) and 0.41 (Endo VIII)) and the lowest with C (0.05 (Endo III) and 0.06 (Endo VIII)). In contrast, mNth1 recognized all Fapy pairs equally well and the activity was comparable to Tg. The results obtained in the nicking assay were further substantiated by the analysis of the Schiff base intermediate using NaBH(4) trapping assays. These results indicate that Escherichia coli and mammalian Tg glycosylases have a potential activity to recognize Fapy. However, as demonstrated for Fapy:C pairs, their distinctive activities implicate unequal participation in the repair of Fapy lesions in cells.     

Preconditioning of brain slices against hypoxia induced injury by a Gynostemma pentaphyllum extract--stimulation of anti-oxidative enzyme expression

A short period of hypoxia/hypoglycaemia (oxygen and glucose deprivation, OGD) induced by perfusion with O(2)/glucose-free medium caused immediate loss and incomplete restoration of evoked field potentials in the CA1 region of transverse hippocampus slices. OGD-dependent decrease in evoked field potentials can be prevented by a proceeding short OGD event (preconditioning). We report about a study investigating the effect of an ethanolic Gynostemma pentaphyllum extract on evoked field potentials when administered before the OGD episode. Using this procedure, the extract completely protected the cells of the slices from functional injury. In an astroglia rich cell culture the ethanolic Gynostemma pentaphyllum extract caused within 48 h of cultivation increased protein and activity levels of the anti-oxidative enzymes manganese superoxide dismutase (Mn-SOD) and glutathione peroxidase (GPx). Consequently, the cellular H(2)O(2) concentration remained at a low level. These data suggest that the Gynostemma pentaphyllum-mediated increase in antioxidative enzyme activities may contribute to the protection of transverse hippocampus slices from OGD induced functional injury. Our results demonstrate that the prophylactic administration of the ethanolic extract from Gynostemma pentaphyllum has a high potential to protect from ischemia/reperfusion injury.     

The effect of Tribulus terrestris extract on motility and viability of human sperms after cryopreservation

BackgroundSemen cryopreservation produces significant amounts of reactive oxygen species (ROS), which may lead to impairment of sperm morphology, function, and ultimately, male fertility. Since Tribulus terrestris has antioxidant and free-radical-scavenging properties, this study aims to reveal the effect of the Tribulus terrestris extract on motility and vitality of human sperms after cryopreservation.Materials and methodsSemen specimens from 80 healthy volunteers were divided into eight groups: fresh control (group I), freeze control (group II), groups III, IV, and V, which had 20, 40, and 50 μg/mL doses of Tribulus terrestris extract added before cryopreservation, and groups VI, VII, and VIII, which were supplemented by these extract doses after the freeze-thaw process. To evaluate the effects of the Tribulus terrestris extract, the semen samples were incubated with the extract and evaluated with a light microscope for motility and viability.ResultsAfter cryopreservation, a significant improvement in spermatozoa viability was observed in group VII. In groups VII and VIII, motility, according to World Health Organization (WHO) criteria, increased considerably (p < 0.001). There was no significant difference among groups III, IV, and V.ConclusionThe present study demonstrated that the protective effects of Tribulus terrestris, which improves human sperm motility and viability, may be due to its antioxidant properties. On the basis of the results, the researchers concluded that Tribulus terrestris can be used as a safe therapeutic alternative to current modalities for the management of motility dysfunction in males.