Effects of Mistletoe (Viscum Album L., Loranthaceae) Extracts on Arterial Blood Pressure in Rats Treated with Atropine Sulfate and Hexocycline

Acute effects of different extracts of mistletoe stem (Viscum album) were investigated on values of arterial blood pressure in Wistar rats. Arterial blood pressure was registered by direct method in the left carotid artery and the investigated extracts (total ethanol, ether and ethyl acetate) of mistletoe stem were administered into the right jugular vein. The total ethanol extract exhibited the best effect even on the lowest applied concentration (3.33 × 10^?5 mg kg^?1) and significantly decreased the blood pressure after applied concentration 1.00 × 10^?3 mg kg^?1. On the contrary, the ether and ethyl acetate extracts exhibited notable activity only by higher administered doses. Atropine as a nonselective blocker of muscarinic receptors reduced the hypotensive effects of ethanol extract of mistletoe. Hexocycline, a selective blocker of muscarine receptors, significantly raised blood pressure and decreased the hypotensive effect of ethanol extract of mistletoe on arterial blood pressure in rats.     

Comparative study on the effects of aqueous extracts of viscum album (mistletoe) from three host plants on hematological parameters in albino rats

Background

The extract of the leaves of Viscum album (mistletoe) has been used for centuries in traditional medicine in many parts of the world. However, like many medicinal plants, the belief that things of natural origin are safe may not be entirely true. The blood is a good indicator of health and pathological mirror of the entire body.

Objective

Therefore, in this study, the acute effects of extracts of mistletoe, harvested from three hosts, on haematology indices of wistar albino rats was investigated.

Methods

Graded doses (400, 800, 1600 and 3200mg/kg body weight) of aqueous extracts of mistletoe from three different host plants, coffee (Coffee arabica), kola (Kola nitida), cocoa (Theobromae cacao), were administered orally to wistar albino rats for 14 days. Full haematological parameters were evaluated on whole blood collected from rats twenty four hours after the administration of the last dose.

Results

Mistletoe from kola caused a concentration dependent and statistically significant (p<0.05) reduction in platelets count in rats. Administration of mistletoe extract from cocoa and coffee led to reduction in hemoglobin concentration. Reductions in packed cell volume (PCV) and red blood cell (RBC) and increase in white blood cells (WBC) were also observed in rats administered all the extracts.

Conclusion

Increase in the WBC count observed in rats administered mistletoe suggests that mistletoe extract contains agents that could stimulate the production of leucocytes and could serve as immune booster. However, there is need to be cautious in administration at high doses to prevent the risk of anaemia.     

槲寄生总黄酮苷对缺氧、心肌缺血及心律失常的预防作用的研究

目的研究槲寄生总黄酮苷对缺氧、急性心肌缺血和心律失常的预防作用.方法采用乙醇和有机溶剂萃取方法从槲寄生中提取总黄酮有效成分;用磨口瓶法观察完全密闭小鼠的存活时间;垂体后叶素(1U/kg)致心肌缺血模型,用分光光度法测LDH、MDA、SOD值;用乌头碱(40μg/kg)建立心律失常模型,观测对室颤发生率等的影响.结果耐缺氧实验中给药组小鼠的平均存活时间显著长于对照组(P＜0.05);在心肌缺血实验中,给药组血清中LDH、MDA、SOD的含量与模型组有显著差异(P＜0.05);在心律失常实验中室性心动过速(VT)、室颤(VF)的发生率有降低趋势,室性早搏出现时间有延长趋势,对窦性节律恢复率没有影响.结论槲寄生总黄酮苷可显著增强小鼠耐缺氧能力;槲寄生总黄酮苷对垂体后叶素引起的大鼠急性心肌缺血损伤具有显著的保护作用;槲寄生总黄酮苷对大鼠心律失常有一定拮抗作用.     

Immunological response to mistletoe (Viscum album L.) in cancer patients: a four‐case series

European mistletoe (Viscum album) has been used in complementary cancer treatment, but little is known concerning its effects on immunological parameters, although there is evidence that Viscum may stimulate the immune system. In this study, a trial was conducted with cancer patients to determine whether Viscum album extracts could improve the results of immune tests. These were: white blood cell count (leukocytes, neutrophils, lymphocytes), CD4+ and CD8+ T‐lymphocytes, intradermal tests of delayed hypersensitivity (candidin, trichophytin, purified protein derivative‐PPD), complement C3 and C4, and immunoglobulin A, G and M. Four patients received seven doses of subcutaneous Viscum album 20 mg, twice weekly. Immunological tests were carried out before and after treatment, and an increase in several parameters of humoral and cellular immunity were shown. Apart from reactions around the injection sites, treatment was well tolerated and all patients benefited from it. These results suggest that Viscum album can enhance humoral and cellular immune responses in cancer patients, but further studies attesting to the possible clinical impact of these immunological effects are necessary. Copyright © 2008 John Wiley & Sons, Ltd.     

Antiviral potency of mistletoe (Viscum album ssp. album) extracts against human parainfluenza virus type 2 in Vero cells

Various extracts from the leaves of mistletoe (Viscum album L. ssp. album) were investigated for their antiviral activity on human parainfluenza virus type 2 (HPIV-2) growth in Vero cells. Plant extracts were prepared using distilled water, 50% ethanol, petroleum ether, chloroform and acetone. The 50% effective dose (ED(50)) of aqueous extract for HPIV-2 replication was 0.53 +/- 0.12 micro g/mL, and the antiviral index (AI), which was based on the ratio of the 50% inhibitory concentration (CD(50)) for host cell viability to the ED(50) for parainfluenza virus replication, was 10.05. The aqueous extract was found to be the most selective inhibitor. Furthermore, the aqueous extract at a concentration of 1 micro g/mL was found to inhibit HPIV-2 replication and the virus production was suppressed to more than 99% without any toxic effect on host cells. The chloroform extract was also found to be moderately active. In an effort to further analyse the mechanism of antiviral activity, the effectiveness of the aqueous extract on different steps of virus replication was examined. The antiviral activity could neither be attributed to the direct inactivation of the HPIV-2 nor to the inhibition of adsorption to Vero cells. The active aqueous extract has shown a dose-dependent antiviral activity on virus replication.     

枫香槲寄生抗肿瘤有效部位总皂苷的提取及含量测定研究

目的探讨枫香槲寄生抗肿瘤有效部位总皂苷的提取工艺条件及含量测定方法。方法采用正交实验法设计提取条件,以齐墩果酸为对照品,用紫外分光光度法测定总皂苷的含量,优化提取方案。结果回收率为100.3%,RSD=1.54%。各因素对总皂苷提取的影响程度依次为:乙醇浓度>提取次数>提取时间>乙醇倍量。结论提取的最佳工艺条件为5倍量60%乙醇回流提取两次,1.5 h/次,该方法稳定,准确,重现性好。     

扁枝檞寄生化学成分的研究Ⅰ

从扁枝槲寄生(Viscum articulatum Burm.f.)中分离得到八个黄酮类化合物。由理化性质及光谱分析鉴定了四种化合物(F2、F4、F6、F8),分别为高圣草素-7-O-β-D-葡萄糖甙,圣草酚-7-O-β-D-葡萄糖甙,槲寄生新甙Ⅰ,槲寄生新甙Ⅴ。四种化合物均为首次从该植物中发现。     

红果槲寄生抗肿瘤有效部位的确定

目的:确定红果槲寄生[Viscum coloratum(Kom.)Nakai f.Rubroaurantiacum Kitag,VCR]的抗肿瘤有效部位。方法:以S180实体瘤小鼠作为动物模型,以抑瘤率为考察指标,对红果槲寄生75%乙醇提取物的不同溶剂萃取部位:石油醚萃取部分、氯仿萃取部分、乙酸乙酯萃取部分、正丁醇萃取部分以及水层部分分别进行了抗肿瘤活性筛选。将接种肿瘤的昆明小鼠在成瘤后按照瘤体大小随机分为7组,阳性对照组于ip环磷酰胺,给药剂量为100 mg·kg-1,其他试验组于同一时间ig给药,每天1次,给药剂量按生药量计为14.2 g·kg-1,空白对照组给予相同剂量的空白溶剂,连续给药8 d。结果:红果槲寄生提取物能明显抑制小鼠S180实体瘤生长,其中正丁醇萃取物组,平均抑瘤率为48.8%;氯仿萃取物组,平均抑瘤率为44.1%。结论:正丁醇和氯仿萃取部分抗肿瘤活性较强,为红果槲寄生抗肿瘤有效部位。     

Mechanisms involved in Korean mistletoe lectin-induced apoptosis of cancer cells

AIM: To investigate the anti-cancer mechanisms of Korean mistletoe lectin (Viscum album coloratum agglutinin,VCA) using a human colon cancer cell line (COLO). METHODS: Cytotoxic effects of VCA on COLO cells were determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay in vitro and tumor-killing effects in vivo. To study the mechanisms involved,the expression of various pro-caspases,anti-apoptotic proteins,and death receptors was determined by western blot. To determine which death receptor is involved in VCA-induced apoptosis of COLO cells,cytotoxicity was examined by MTT assay after treatment with agonists or antagonists of death receptors. RESULTS: VCA killed COLO cells in a time-and dose-dependent manner and induced complete regression of tumors in nude mice transplanted with COLO cells. Treatment of COLO cells with VCA activated caspase-2,-3,-8,and -9 and decreased expression of anti-apoptotic molecules including receptor interacting protein,nuclear factor-κB,X-linked inhibitor of apoptosis protein,and Akt/protein kinase B. We then examined the involvement of death receptors in VCA-induced apoptosis. Only tumor necrosis factor receptor 1,among the death receptors examined,was involved in apoptosis of COLO cells,evidenced by inhibition of VCA-induced apoptosis and decreased activation of caspases,particularly caspase-8,by tumor necrosis factor receptor 1 antagonizing antibody.CONCLUSION: VCA-induced apoptotic COLO cell death is due to the activation of caspases and inhibition of anti-apoptotic proteins,in part through the tumor necrosis factor receptor 1 signaling pathway.     

槲寄生黄酮苷对大鼠心肌缺血的保护作用及其机制

目的 观察槲寄生黄酮苷对心肌缺血大鼠的保护作用,并进一步明确其对血小板激活因子 (PAF) 的调控作用。方法 结扎大鼠冠状动脉左前降支造成急性心肌梗死模型,通过观察不同剂量槲寄生黄酮苷 (15、75 mg/kg) 及 PAF 受体特异性阻断剂 BN52021 (10 mg/kg) 对梗死范围的影响,对比评价槲寄生黄酮苷对缺血心肌的保护作用;分离正常大鼠心肌细胞,Fluo-3/AM 荧光染色,采用共聚焦显微镜技术研究,预先给予不同剂量槲寄生黄酮苷 30 min 后对 PAF (1×10^-11 mol/L) 诱导心肌细胞钙超载的拮抗作用。结果 与模型组比较,槲寄生黄酮苷和 BN52021 均可缩小大鼠梗死心肌范围,降低心肌梗死大鼠血清乳酸脱氢酶 (LDH),丙二醛 (MDA) 水平,提高血清超氧化物歧化酶 (SOD) 水平,并成剂量效应关系。PAF 可直接诱导心肌细胞钙超载,而槲寄生黄酮苷和 BN52021 可直接对抗这种钙超载作用。结论 槲寄生黄酮苷对心肌缺血具有保护作用,作用机制与其抑制 PAF 诱导心肌细胞内钙超载有关,PAF 信号通路阻断药物可能成为抗心肌缺血药物的研究靶点。