人参皂苷Rg3抗肿瘤作用机制的研究新进展

人参皂苷Rg3是从五加科植物人参中提取的重要活性成分之一,其可通过抑制肿瘤细胞增殖,调节机体免疫力,促进肿瘤细胞凋亡,逆转耐药性,减少肿瘤内血管生成,抑制肿瘤细胞的侵袭和转移,联合放、化疗药物减毒增效等发挥抗肿瘤的作用。本文主要对近年来人参皂苷Rg3抗肿瘤的作用机制的研究进展做一综述。     

人参皂苷Rg3抗肿瘤作用机制的研究进展

人参作为传统中药家喻户晓,其提纯的重要活性成分之一一一人参皂苷Rg3,在科研中发现,具有多方向、多“靶点”抗肿瘤作用,并在临床治疗中不断被证实和推广.目前发现:人参皂苷Rg3具有抑制肿瘤细胞增殖作用;通过激活凋亡基因活性或抑制凋亡抑制蛋白等,从而促进肿瘤细胞凋亡;抑制肿瘤细胞的侵袭和转移;抑制肿瘤血管生成因子的信号传导途径,促进肿瘤血管生成抑制因子的表达,从而抑制肿瘤新生血管形成;与部分化学药物联合,可明显提高效果,同时对临床患者无明显血液系统毒性,并提高生活质量等作用.近年临床及体外实验证明,人参皂苷Rg3对多个系统并以不同机制发挥抗肿瘤作用,而对其研究仍在不断探索新的方向.作为祖国传统中药中提纯的单体抗肿瘤药物,在现今综合抗肿瘤治疗中意义深刻.     

人参皂苷活性单体-20(R)-人参皂苷Rg3药理作用及其机制的研究进展

20(R)-人参皂苷Rg3是人参皂苷的主要活性单体之一,主要用于抗肿瘤治疗。近年来,20(R)-人参皂苷Rg3的药理作用不断取得进展,其中保护心脑血管、增强免疫功能、抗增生性瘢痕、抗疲劳的药理作用尤为值得关注。本文整理近年来国内外与20(R)-人参皂苷Rg3相关文献,论述其主要药理作用及其作用机制,为进一步开发20(R)-人参皂苷Rg3提供了科学依据。     

人参皂苷Rg1、Rb1和Re对人慢性粒细胞白血病细胞株K562增殖的影响

目前已发现30余种人参皂苷单体,不同的人参皂苷单体的药理作用及机制各异。本实验通过研究人参皂苷单体Rg1、Rb1和Re对K562细胞增殖的影响,探讨其抗肿瘤作用及机制。取对数生长期K562细胞,分为阴性对照组、不同浓度的Rg1组、Rb1组、Re组,培养24h、48h、72h,以噻唑蓝（MTT）比色法和台盼蓝活细胞计数法测定不同浓度的Rg1、Rb1、     

一种真菌对人参皂苷Rg3的转化

[目的]筛选长白山人参土壤中的活性微生物,转化人参总皂苷及单体人参皂苷产生稀有抗肿瘤成份.[方法]从长白山人参根际土壤中分离各类菌株,对人参总皂苷及单体人参皂苷进行微生物转化,并通过硅胶柱层析等方法对转化产物进行分离纯化,采用波谱解析及理化常数对其进行结构鉴定;结合菌落形态、产孢结构、孢子形态特征以及菌株ITS rDNA核酸序列分析,对活性菌株进行鉴定.[结果]从长白山人参根际土壤中分离各类真菌菌株68株,有12株菌株对人参总皂苷有转化活性,其中菌株SYP2353对二醇组人参皂苷Rg3具有较强的转化活性.[结论]阳性菌株SYP2353被鉴定为疣孢漆斑菌(Myrothecium verrucaria),能将人参皂苷Rg3转化为稀有人参皂苷Rh2及二醇组人参皂苷苷元PPD,为稀有人参皂苷Rh2的制备提供了新的方法.     

黑根霉对人参皂苷Re的生物转化

利用菌种黑根霉Rhizopus sp.对人参皂苷Re进行生物转化,并对人参皂苷Re及其发酵产物进行HPLC系统分析比较,经液相色谱-质谱分析得出人参皂苷Re转化率为92.16%,并制备出人参皂苷Re发酵产物中峰值升高的成分,转化后的人参皂苷发酵产物中化合物1确定为人参皂苷Rg2,化合物2为Rg2的同分异构体,得率为10.13%;化合物3和化合物4确定为人参皂苷Rg5/Rk1,得率为29.23%。从结果初步推测得出人参皂苷Re被黑根霉转化为人参皂苷Rg2的机理,人参皂苷Re转化成人参皂苷Rg5/Rk1的机理还有待于进一步研究。     

西洋参茎叶化学成分及生物利用度的研究

应用多种色谱技术进行分离纯化,从西洋参茎叶中分离得到10个化合物,经理化性质和光谱数据分析鉴定分别为:拟人参皂苷RT4(1)、拟人参皂苷RT5(2)、24(R)-Ocotillol苷元(3)、20(S)-人参皂苷Rh1(4)、20(S)-人参皂苷Rg1(5)、20(S)-人参皂苷Rg2(6)、20(S)-人参皂苷Rh2(7)、20(R)-人参皂苷Rh2(8)、20(S)-人参皂苷Rg3(9)、拟人参皂苷F11(10)。化合物1和3为首次从西洋参茎叶中分离得到。首次建立和认证了20(S)-人参皂苷Rg3肌内注射的生物利用度的测定方法,采用本文方法测定犬肌注20(S)-人参皂苷Rg3的生物利用度为96.7%,为20(S)-人参皂苷Rg3的新药开发提供了临床前药代动力学依据。     

人参皂苷Rg1通过Wnt3a/β-catenin信号通路影响糖尿病大鼠肾损伤的机制研究

摘要 目的：研究人参皂苷Rg1通过Wnt3aβ-catenin信号通路影响糖尿病大鼠肾损伤的机制。方法：将60只SD大鼠随机分为对照组、模型组、厄贝沙坦组、人参皂苷Rg1组。模型组、厄贝沙坦组、人参皂苷Rg1组经腹腔注射链脲佐菌素建立糖尿病模型,给予对照组、模型组生理盐水灌胃,厄贝沙坦组接受厄贝沙坦干预,人参皂苷Rg1组接受人参皂苷Rg1干预,各组均连续干预8周。比较各组大鼠血糖血脂水平、Wnt3a/β-catenin表达、肾损伤及肾脏炎症指标。结果：与对照组相比,人参皂苷Rg1组、厄贝沙坦组、模型组空腹血糖、总胆固醇、甘油三酯水平依次升高（P<0.05）。与对照组相比,人参皂苷Rg1组、厄贝沙坦组、模型组Wnt3a、β-catenin表达水平依次升高（P<0.05）。与对照组相比,人参皂苷Rg1组、厄贝沙坦组、模型组血肌酐、尿素氮、24 h尿蛋白水平依次升高（P<0.05）。与对照组相比,人参皂苷Rg1组、厄贝沙坦组、模型组C反应蛋白、单核细胞趋化蛋白-1、肿瘤坏死因子-α水平依次升高（P<0.05）。结论：人参皂苷Rg1可有效调节糖尿病大鼠血糖血脂水平,抑制肾脏炎症反应,缓解肾损伤,调控Wnt3a/β-catenin信号通路可能是其发挥作用的重要机制。     

人参生殖器官皂苷含量动态变化

为了明确从现蕾、开花到结实过程中的人参生殖器官中各单体皂苷含量的动态变化,应用HPLC法测定了人工栽培的五年生人参不同时期生殖器官中的人参单体皂苷Rb1、Rb2、Rb3、Rc、Rd、Re、Rg1和Rg3的含量。结果显示:从现蕾到果实成熟的过程中,人参单体皂苷Rb1、Rb2、Rb3、Rc、Rd、Re、Rg1和Rg3的含量的平均值分别为0.643%,0.189%,1.026%,1.014%,1.941%,8.381%,0.724%和0.041mg.g-1。从现蕾到果实成熟的过程中,人参单体皂苷Rb1含量的最高值在7月16日,单体皂苷Rb3、Rc、Rd和Rg1含量的最高值在7月11日,单体皂苷Rb2和Rg2含量的最高值在8月7日。     

人参皂苷生物合成和次生代谢工程

人参皂苷属于植物三萜皂苷类化合物,是传统名贵药材人参和西洋参的主要活性成分,具有抗炎、抗氧化作用,还有广泛的抗肿瘤作用。人参皂苷与植物甾醇共享前期代谢途径,通过2, 3-氧化鲨烯环化步骤进入三萜代谢分支途径,在三萜碳环骨架复杂修饰的基础上形成人参皂苷。综述了近年人参皂苷生物合成途径及关键酶基因研究的最新进展,揭示了人参皂苷生物合成的基本途径,对途径中关键酶的基因进行了综述,并结合次生代谢工程技术, 探讨了该技术在人参皂苷生物合成中的应用前景。     

Proteomic analysis effects of ginsenoside Rg1 on human umbilical vein endothelial cells stimulated by tumor necrosis factor-alpha

Ginsenoside Rg1 (derived from ginseng root) has been found to have many vasoprotective activities. The present study was undertaken to examine effect of ginsenoside Rg1 on the secretion of nitric oxide (NO) in human umbilical vein endothelial cells (HUVECs) stimulated with or without tumor necrosis factor-alpha (TNF-alpha). We showed here that ginsenoside Rg1 can increase the basal and TNF-alpha-attenuated NO production in a dose-dependent manner. As little is known regarding the vascular molecular mechanism of ginsenoside Rg1 on HUVECs and proteomic technique has more advantages in molecular identification, we attempted to use proteomic analysis to explain vascular molecular mechanism of ginsenoside Rg1 on HUVECs. Proteomic analytical result showed that 21 protein spots were changed in TNF-alpha stimulated HUVECs, including 9 up-regulated spots, 11 down-regulated spots, and 1 spot detected in TNF-alpha stimulated group only. The expression level of proteins such as MEKK3, phosphoglycerate mutase was increased, and nitric-oxide synthase, mineralocorticoid receptor were decreased in TNF-alpha stimulated HUVECs, while ginsenoside Rg1 could prevent this change or reverse to some degree. This study suggested that NO production increased via ginsenoside Rg1 played an important role in the protective effect on TNF-alpha stimulated HUVECs and was helpful to deeply understand the active mechanism of ginsenoside Rg1 to HUVECs at the molecular level.     

Stimulation of Rg3 ginsenoside biosynthesis in ginseng hairy roots elicited by methyl jasmonate

It has been recognized that ginsenoside Rg3 is not naturally produced in ginseng although this ginsenoside can accumulate in red ginseng as the result of a thermal process. In order to determine whether or not Rg3 is synthesized in ginseng, hairy roots were treated with methyl jasmonate (MJ). From HPLC analysis, no peak for Rg3 was observed in the controls. However, Rg3 did accumulate in hairy roots that were MJ-treated for 7?days. Rg3 content was 0.42?mg/g (dry weight). To gain more insight into the effects of MJ on UDP-glucosyltransferase (UGT) activity, we attempted to evaluate ginsenoside Rg3 biosynthesis by UGT. A new peak for putative Rg3 was observed, which was confirmed by LC-MS/MS analysis. Our findings indicate that the proteins extracted from our hairy root lines can catalyze Rg3 from Rh2. This suggests that our ginseng hairy root lines possess Rg3 biosynthesis capacity.     

Protective effect of ginsenoside Rg3 on lung injury in diabetic rats

Ginsenoside has been used to treat diabetes, while ginsenoside Rg3 is the main active ingredient component of ginseng and is used to study its effects on lung tissue damage in diabetic rats. In this paper, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and flow cytometry were applied to detect the proliferation and apoptosis of BEAS-2B cells treated with different concentrations of Rg3. The inflammatory response and pathological change in the lung tissue of diabetic rats treated with Rg3 were evaluated by enzyme-linked immunosorbent assay, quantative real-time polymerase chain reaction, and hematoxylin and eosin staining immunohistochemistry. Meanwhile, PI3K and MAPK signaling pathway proteins in lung tissue were determined by Western blot analysis. The results showed that ginsenoside Rg3 had no significant influence on the proliferation and apoptosis of BEAS-2B cells. Ginsenoside Rg3 can inhibit inflammatory response and promote the activation of PI3K and MAPK signaling pathways to prevent damages of lung tissues induced by hyperglycemia. The protective effect provided by ginsenoside Rg3 indicates that ginsenoside Rg3 is a potential drug for the treatment of diabetes.     

Ginsenoside Rg3 antagonizes NMDA receptors through a glycine modulatory site in rat cultured hippocampal neurons

We previously reported that ginseng, a well-known herbal medicine, inhibited NMDA receptors in cultured hippocampal neurons. Here, we further examined the detailed mechanism of ginseng-mediated inhibition using its main active ingredient, ginsenoside Rg3. Co-application of ginsenoside Rg3 with increasing concentrations of NMDA did not change the EC50 of NMDA to the receptor, suggesting that ginsenoside Rg3 inhibits NMDA receptors without competing with the NMDA-binding site. Ginsenoside Rg3-mediated inhibition also occurred in a distinctive manner from the well-characterized NMDA receptor open channel blocker, MK-801. However, ginsenoside Rg3 produced its effect in a glycine concentration-dependent manner and shifted the glycine concentration-response curve to the right without changing the maximal response, suggesting the role of ginsenoside Rg3 as a competitive NMDA receptor antagonist. We also demonstrated that ginsenoside Rg3 significantly protected neurons against NMDA insults. Therefore, these results suggest that ginsenoside Rg3 protects NMDA-induced neuronal death via a competitive interaction with the glycine-binding site of NMDA receptors in cultured hippocampal neurons.     

Effects of ginsenoside Rg2 on the 5-HT3A receptor-mediated ion current in Xenopus oocytes

Treatment with ginsenosides, major active ingredients of Panax ginseng, produces a variety of pharmacological or physiological responses with effects on the central and peripheral nervous systems. Recent reports showed that ginsenoside Rg2 inhibits nicotinic acetylcholine receptor-mediated Na+ influx and channel activity. In the present study, we investigated the effect of ginsenoside Rg2 on human 5-hydroxytryptamine3A (5-HT3A) receptor channel activity, which is also one of the ligand-gated ion channel families. The 5-HT3A receptor was expressed in Xenopus oocytes, and the current was measured using the two-electrode voltage clamp technique. The ginsenoside Rg2 itself had no effect on the oocytes that were injected with H2O as well as on the oocytes that were injected with the 5-HT3A receptor cRNA. In the oocytes that were injected with the 5-HT3A receptor cRNA, the pretreatment of ginsenoside Rg2 inhibited the 5-HT-induced inward peak current (I5-HT) The inhibitory effect of ginsenoside Rg2 on I5-HT was dose dependent and reversible. The half-inhibitory concentrations (IC50) of ginsenoside Rg2 was 22.3 +/- 4.6 microM. The inhibition of I5-HT by ginsenoside Rg2 was non-competitive and voltage-independent. These results indicate that ginsenoside Rg2 might regulate the 5-HT3A receptors that are expressed in Xenopus oocytes. Further, this regulation on the ligand-gated ion channel activity by ginsenosides might be one of the pharmacological actions of Panax ginseng.     

Conversion of major ginsenoside Rb1 to 20(S)-ginsenoside Rg3 by Microbacterium sp. GS514

Ginseng saponin, the most important secondary metabolite in ginseng, has various pharmacological activities. Many studies have been directed towards converting major ginsenosides to the more active minor ginsenoside, Rg3. Due to the difficulty in preparing ginsenoside Rg3 enzymatically, the compound has been mainly produced by either acid treatment or heating. A microbial strain GS514 was isolated from soil around ginseng roots in a field and used for enzymatic preparation of the ginsenoside Rg3. Blast results of the 16S rRNA gene sequence of the strain GS514 established that the strain GS514 belonged to the genus Microbacterium. Its 16S rRNA gene sequence showed 98.7%, 98.4% and 96.1% identity with those of M. esteraromaticum, M. arabinogalactanolyticum and M. lacticum. Strain GS514 showed a strong ability to convert ginsenoside Rb1 or Rd into Rg3. Enzymatic production of Rg3 occurred by consecutive hydrolyses of the terminal and inner glucopyranosyl moieties at the C-20 carbon of ginsenoside Rb1 showing the biotransformation pathway: Rb1-->Rd-->Rg3.     

Relaxation of canine corporal smooth muscle relaxation by ginsenoside saponin Rg3 is independent from eNOS activation

It has been reported that nitric oxide (NO) is involved in the relaxation mechanism of ginsenoside saponin in various smooth muscle in experimental animals. Although ginsenoside Rg(3) showed both endothelium-dependent and -independent component relaxation in vascular smooth muscle, the action mechanism of the relaxation of corporal muscle is not clear. We, thus, investigated the relaxation mechanism of ginsenoside Rg(3) using isolated canine corpus cavernosum. Ginsenoside Rg(3) concentration-dependently relaxed the canine corpus cavernosum that had been contracted by phenylephrine (PE), in which IC(50) was 1.68 x 10(-5) g/ml. Ginsenoside Rg(3) significantly (P < 0.05) potentiated acetylcholine (ACh)-induced relaxation in endothelium intact corpus cavernosum. Methylene blue (MB) but not N(omega)-nitro-L-arginine methylester (L-NAME) or ODQ (1H-[1,2,4]oxadiazol-[4,3-]quinoxsalin-1-one) modified the dose-response curve of ginsenoside Rg(3). Ginsenoside Rg(3) also significantly potentiated relaxation response to UV light in the presence of streptozotocin (STZ), which was almost completely (P < 0.01) blocked by ODQ. Ginsenoside Rg(3) concentration-dependently inhibited corporal phosphodiesterases (PDE), which resulted in increase of cyclic adenosine monophosphate (cAMP) as well as cyclic guanosine monophosphate (cGMP) contents in corporal smooth muscles. MB inhibited the accumulation of cGMP but not cAMP by ginsenoside Rg(3). These results indicate that mechanism responsible for the relaxation by ginsenoside Rg(3) is not by stimulating endothelial nitric oxide synthase (eNOS) of the canine corporal smooth muscle but by increasing cyclic nucleotide levels through PDE inhibition.     

Ginsenoside Rg1 inhibits tumor necrosis factor-alpha (TNF-alpha)-induced human arterial smooth muscle cells (HASMCs) proliferation

In China, the ginseng root began to be used in medicine over 2000 years ago. Ginsenosides are the most important component isolated from ginseng. The aim of this study was to determine the effects of ginsenoside Rg1 on the proliferation and molecular mechanism in cultured human arterial vascular smooth muscle cell (HASMC) induced by tumor necrosis factor-alpha (TNF-alpha). It was shown that ginsenoside Rg1 significantly inhibited TNF-alpha-induced HASMC proliferation in a dose-dependent manner. Treatment with ginsenoside Rg1, which blocked the cell cycle in the G1-phase, induced a downregulation of cyclin D1 and an upregulation in the expression of p53, p21(WAF/CIP1), and p27(KIP1). MEK inhibitors PD98059, U0126, and phosphatidylinositol 3-kinase (PI3K) inhibitor wortmannin, but not p38-inhibitor SB203580 or JNK-inhibitor SP600125 significantly aggravated ginsenoside Rg1-inhibited HASMC proliferation. Ginsenoside Rg1 markedly inactivated the extracellular signal-regulated kinases (ERK1/2) and protein kinase B (PKB), indicating that the inhibition of ginsenoside Rg1 on HASMC proliferation was associated with ERK and PI3K/PKB pathways. The inactivation of ERK and PI3K/PKB pathways and modulation of cell-cycle proteins by ginsenoside Rg1 may be of importance in inhibition of HASMCs proliferation.     

人参皂甙Rg1与1,6-二磷酸果糖配伍抗疲劳作用的研究

观察人参皂甙Rg1与1,6-二磷酸果糖配伍的抗疲劳效果,寻找最佳配伍剂量。根据雄性清洁级昆明种小鼠按体重随机分为安静对照组、运动对照组、人参皂甙Rg1对照组及4个配伍组。通过析因实验设计分析人参皂甙Rg1与1,6-二磷酸果糖提高运动耐力的效果及两者的交互作用。结果不同剂量人参皂甙Rg1对小鼠力竭游泳时间影响有显著差异(P<0.05)。各配伍组力竭游泳时间均有显著延长,C组延长最显著;与人参皂甙Rg1对照组相比,各配伍组力竭游泳时间均显著降低(P<0.01)。MDA含量A组显著低于运动对照组和D组,与安静对照组相比,各组均升高。SOD/MDA比值A、C组显著高于运动对照组,C组显著高于人参皂甙Rg1对照组,与安静对照组相比,各组均有下降趋势,D组下降最显著(P<0.01)。乳酸脱氢酶C、D组显著低于运动对照组和人参皂甙Rg1对照组(P<0.05)。与运动对照组及人参皂甙Rg1对照组相比,配伍在一定程度上减少心肌、骨骼肌细胞线粒体和其他细胞超微结构损伤。结论:与FDP配伍未能延长小鼠力竭游泳时间,配伍可减轻耐力运动对小鼠心肌和骨骼肌的细胞损害,一定程度上保护线粒体的呼吸功能,缓解细胞缺氧损伤。