完达山地区槲寄生（Viscum coloratum）种群特征研究

于2012年4-11月对老平岗林场6个群落中7种寄主上的槲寄生（Viscum coloratum）种群进行了研究,结果表明：以寄主为单位,槲寄生的最终分布格局取决于寄主的格局;而在每个寄主上则呈聚集性分布。从数量上看,寄生强度为：山杨＂白桦＂辽东桤木＂黑桦＂紫椴=青楷槭＂色木槭;各寄主上单株槲寄生平均结果量为：山杨＂白桦＂辽东桤木＂青楷槭＂紫椴＂色木槭＂黑桦;红黄两种果实型植株的比例近于1∶1。从遗传上看,槲寄生表现出过量繁殖特征;其种子传播与太平鸟存在密切联系,经鸟类粪便排出的种子82%落在地面,15%黏附在下层灌木上,3%附着在寄主树干上。本研究认为：寄主的分布格局,寄主所在群落的组成及发育,传播者的生活习性和槲寄生自身的繁殖策略是影响其种群的主要因素。     

槲寄生的研究与开发利用

本文对槲寄生的生物学特性、化学成分、药理作用及开发利用等作了阐述。     

槲寄生中多肽B6的分离纯化和一级结构测定

采用离子交换、凝胶过滤、HPLC等提取、分离、纯化方法,从我国东北产槲寄生中得到第二种新成分槲寄生毒素B6。Edman降解结合质谱技术测定其一级结构为KSCCPNTTGRNIYNTCRFAGASRERCAKLSGCKIISASTCPSDYPK。进化分析说明该成分与白果槲寄生中的槲寄生毒素同源性很高,亲缘关系较近。同源模建表明B6是一种高α-螺旋的多肽。     

Chemical constituents of Viscum album var. meridianum

Twenty known compounds were isolated from Viscum album L. var. meridianum Danser. As major compounds, flavanones, flavanone glycosides and triterpenenes could be chemotaxonomic markers for the genus Viscum according to our study and literatures.     

槲寄生的生物学特征及鸟类对其种子的传播

2001年9月至2002年1月在黑龙江省尚志市帽儿山林场研究了槲寄生(Viscum coloratum)的生物学特征及鸟类对其种子的传播。槲寄生寄主共有9种阔叶树,杨树占比例最大,达73．3％。78．0％的槲寄生个体以杨树为寄主。多数槲寄生着生在杨树主干侧枝(43％)和细侧枝(42％)上,主干上仅l5％。寄主和槲寄生本身都呈聚集分布。槲寄生有两种色型果实,在量度上无明显差异。果实由果皮、果肉和种子构成,种子外面包裹一层胶质层。在帽儿山秋、冬季常见的7种食果实鸟类中,只有太平鸟（Bombycilla garrulus)在野外觅食槲寄生果实,斑鸫（Turdus naumanii)在笼养无其它食物时才食,其余5种鸟类拒食。太平鸟在11月以后觅食槲寄生果实频率增大。除根寄生果实外,太平鸟共可食帽儿山常见l7种肉质果中的12种。太平鸟在吞食果实后,种子外包胶质层随粪便排出,形成“种子线”粘在树枝上,槲寄生种子被传播到适宜的生境,在春天萌根生长。笼养太平鸟时,种子在消化道的滞留时间约11min,这意味着在野外很长的扩散距离。槲寄生和太平鸟之间形成了特定的互利互生系统。     

Mistletoe lectin (Viscum album coloratum) modulates proliferation and cytokine expressions in murine splenocytes

It is well documented that an extract of European mistletoe has a variety of biological effects, such as the stimulation of cytokine production from immune cells, and additional immunoadjuvant activities. While the European mistletoe has been studied intensively, we know less about Korean mistletoe as a therapeutic plant, especially as a possible immunomodulating drug. This study will investigated the effects of Korean mistletoe lectin (Viscum album L. var. coloratum agglutinin, VCA) on murine splenocytes to investigate whether VCA acts as an immunomodulator, which could lead to improved immune responses in these cells. The results showed that VCA inhibited cell proliferation at higher concentrations (at 1-8 ng/ml) and enhanced cell proliferation at lower concentrations (at 4-32 pg/ml). Further studies were carried out to determine if the proproliferative or anti-proliferative activity exhibited by VCA was correlated with cytokine secretion. Consequently, interferon (IFN)-gamma secretion was decreased in concanavalin A (ConA)-stimulated murine splenocytes by VCA (4-64 ng/ml), but there was no change in IL-4 levels. This suggests that VCA has the ability to modulate murine splenocyte proliferation and can possibly act on the balance of Th1/Th2 cellular immune responses.     

Involvement of caspase-3 in apoptosis induced by Viscum album var. coloratum agglutinin in HL-60 cells

A cytotoxic lectin (Viscum album L. coloratum agglutinin, VCA) from Korean mistletoe was isolated by affinity chromatography on Sepharose 4B immobilized with asialofetuin. In HL-60 cells, addition of VCA resulted in a dose- and time-dependent growth suppression, morphological changes of apoptotic nuclei, and DNA fragmentation characteristics of apoptosis. To investigate how caspase-3 activation during VCA-induced apoptosis induces cleavages of PARP, the expression of PARP and the pattern of caspase-3 activation in HL-60 cells were investigated. The native and processed PARP forms typically seen in apoptotic cells were observed, and a decrease in expression of the 32-kDa form of caspase-3 in a dose-dependent manner was observed. The VCA-induced apoptosis was significantly inhibited by a caspase-3 specific inhibitor, z-DEVD-FMK, and the PARP processing and caspase-3 activation were also inhibited by the inhibitor. A possible involvement of cell cycle arrest in VCA-induced apoptosis was investigated by flow cytometry and the results suggested that the apoptotic effect of VCA is not involved in the induction of cell cycle arrest.     

Cytotoxic constituents of Achillea clavennae from Montenegro

Examination of the aerial parts of Achillea clavennae afforded eight guaianolides (1-8), three bisabolenes (9-11), four flavonols (12-15), sesamin (lignan) and isofraxidin (coumarin). The structures of the new compounds (2, 4, 5, 7 and 10) were determined by spectroscopic methods. The antiproliferative action of 2, 8, 9 and 12 were tested to HeLa, K562 and Fem-X human cancer cell lines. Guaianolides 2 (9alpha-acetoxyartecanin) and 8 (apressin) showed significant cytotoxic effects to all tested lines and inducumenone (9) exhibited a moderate activity. The most active was flavonol centaureidin (12), already known as cytotoxic compound.     

Cytotoxic and aromatic constituents from Salvia miltiorrhiza

As part of an ongoing study of traditional Chinese medicinal plants, the root tissue of Salvia miltiorrhiza was further investigated for its chemical constituents. Five naturally occurring products along with 13 known constituents were isolated from an ethyl acetate-soluble portion of its ethanol extract. Their structures were elucidated by means of spectroscopic methods. Some selected compounds were also evaluated for biological activity.     

Cytotoxic constituents from the roots of Tovomita brevistaminea

Two known xanthones, trapezifolixanthone and manglexanthone were isolated as cytotoxic constituents from the CHCl3 extract of the roots of Tovomita brevistaminea by bioassay-guided fractionation using the KB cell line. In addition, a new compound, tovophenone C, and two known compounds, tovophenones A and B which are benzophenones, were found to be inactive constituents in this investigation. The structure of the new isolate was determined by detailed analysis of spectroscopic parameters including its 1D and 2D NMR spectroscopy data.     

The effect of mistletoe, Viscum album coloratum, extract on innate immune response of Nile tilapia (Oreochromis niloticus)

The purpose of the present study was to evaluate the effect of dietary mistletoe extracts on non-specific immune response and disease resistance of Nile tilapia (Oreochromis niloticus) against Aeromonas hydrophila infection. Tilapia fingerlings were fed with a diet containing 0 mg as a control, 10 mg, 50 mg, and 200 mg mistletoe powder kg(-1) dry diet for 80 days. The immunological parameters, respiratory burst activity, lysozyme activity, alternative complement haemolysis activity (ACH(50)), and phagocytic activity of fish were investigated following 20, 40 and 80 days of feeding. Fish were challenged with A. hydrophila on 80 days after feeding and mortalities were checked over 10 days post-infection. The results show that fish fed with mistletoe extract exhibited an increase in activity in all immunological parameters (P < 0.05) compared to the control group depending on feeding periods and doses of mistletoe. Following challenge with A. hydrophila, 42% less survivability was observed in the control group than in other experimental diet groups. The highest survival rate (83%) was shown in the group fed with a 50 mg mistletoe kg(-1) diet. The results suggest that mistletoe enables tilapia to promote immunity and be more resistant to A. hydrophila infection.     

Viscolin, a new chalcone from Viscum coloratum, inhibits human neutrophil superoxide anion and elastase release via a cAMP-dependent pathway

The mistletoe Viscum coloratum is used in traditional Chinese medicine to treat inflammatory diseases. In this study, a cellular model in isolated human neutrophils, which are important in the pathogenesis of rheumatoid arthritis, chronic obstructive pulmonary disease, and other inflammatory diseases, was established to elucidate the anti-inflammatory functions of V. coloratum. The partially purified extract of V. coloratum (PPE-SVC) potently inhibited formyl-L-methionyl-L-leucyl-L-phenylalanine (FMLP)-induced superoxide anion generation and elastase release in a concentration-dependent manner with IC(50) values of 0.58+/-0.03 and 4.93+/-0.54 microg/ml, respectively. Furthermore, a new chalcone derivative, viscolin (4',4'-dihydroxy-2',3',6',3'-tetramethoxy-1,3-diphenylpropane), was isolated from PPE-SVC. Viscolin was demonstrated to inhibit superoxide anion generation and elastase release, as well as to accelerate resequestration of cytosolic calcium in FMLP-activated human neutrophils. Furthermore, the inhibitory effects of viscolin were reversed by protein kinase A (PKA) inhibitor, suggesting that PKA mediates the viscolin-caused inhibitions. Viscolin induced a substantial increase in cAMP levels, and that occurred through the inhibition of phosphodiesterase (PDE) activity but not an increase in adenylate cyclase function. Consistent with this, viscolin potentiated the PGE(1)-caused inhibition of superoxide anion release and calcium mobilization, as well as elevation of cAMP formation. These results demonstrate that inhibition of inflammatory responses in human neutrophils by viscolin is associated with an elevation of cellular cAMP through inhibition of PDE. Comparable results were also observed by PPE-SVC, indicating that the effect of PPE-SVC is at least partly mediated by viscolin. In summary, viscolin is a novel inhibitor of PDE and might be useful for treatment of neutrophilic inflammation.     

The Identification of in Vitro Production of Lectin from Callus Cultures of Korean Mistletoe (Viscum album L. var. coloratum)

The hydrolysis of the bacterial spore peptidoglycan (cortex) is a crucial event in spore germination. It has been suggested that SleC and SleM, which are conserved among clostridia, are to be considered putative cortex-lytic enzymes in Clostridium perfringens. However, little is known about the details of the hydrolytic process by these enzymes during germination, except that SleM functions as a muramidase. Muropeptides derived from SleC-digested decoated spores of a Bacillus subtilis mutant that lacks the enzymes, SleB, YaaH and CwlJ, related to cortex hydrolysis were identified by amino acid analysis and mass spectrometry. The results suggest that SleC is most likely a bifunctional enzyme possessing lytic transglycosylase activity and N-acetylmuramoyl-L-alanine amidase activity confined to cross-linked tetrapeptide-tetrapeptide moieties of the cortex structure. Furthermore, it appears that during germination of Clostridium perfringens spores, SleC causes merely small and local changes in the cortex structure, which are necessary before SleM can function.     

Cytotoxic and antimalarial constituents from the roots of Eurycoma longifolia

Sixty-five compounds were isolated from the roots of Eurycoma longifolia and characterized by comprehensive analyses of their 1D and 2D NMR, and mass spectral data. Among these isolates, four quassinoid diterpenoids were reported from natural sources for the first time, namely eurycomalide A (1), eurycomalide B (2), 13beta, 21-dihydroxyeurycomanol (3), and 5alpha, 14beta, 15beta-trihydroxyklaineanone (4). Screening of cytotoxicity, anti-HIV and antimalarial activity of these isolated compounds was also furnished by in vitro assays. Compounds 12, 13, 17, 18, 36, 38, 59, and 62 demonstrated strong cytotoxicity toward human lung cancer (A-549) cell lines, however, 12, 13, 17, 38, 57, 58, and 59 exhibited strong cytoxicity toward human breast cancer (MCF-7) cell lines. Compounds 57 and 58 displayed potent antimalarial activity against the resistant Plasmodium falciparum. The thorough studies on the stereochemistry of the different quassinoid diterpenoids provide a clear reference to the scientists who are interested on this field.     

Cytotoxic and antimalarial constituents from aerial parts of Sphaeranthus indicus

Two new eudesmanolide type sesquiterpenes, indicusalactone (1) and (⿿)⿿-⿿oxyfrullanolide (2), along with twelve known compounds (3⿿14), were isolated from the aerial parts of Sphaeranthus indicus. The structures of these compounds were established on the basis of their 1D and 2D NMR spectroscopic data. Compounds 1⿿4 and 12⿿14 showed antimalarial activity against Plasmodium falciparum with IC₅₀ values ranging from 2.32 to 6.47μg/mL. In addition, compounds 2⿿5 showed cytotoxicity against cancer cell lines, KB, NCI-H187 and MCF-7 with IC₅₀ values within the range 1.23⿿46.19 μg/mL.     

Influence of the parasite Viscum cruciatum Sieber on the chemical constituents of Crataegus monogyna Jacq

A phytochemical study of two plant species, Viscum cruciatum Sieber and Crataegus monogyna Jacq., was completed to investigate the influence of the parasite Viscum cruciatum on the host Crataegus monogyna. The study was carried out with two samples and consisted of hexane extracts of the Viscum cruciatum parasitizing on Crataegus monogyna and C monogyna. In these samples ursolic acid, beta-sitosterol and a triterpene fraction were found that contained mainly butyrospermol (3beta-lanost 8, 24-dien, 3-ol), 24-methylene-24-dihydrolanosterol (24-methylene-5alpha-lanost-8-en-3beta-ol), cycloartenol (9beta, 19-cyclo-5alpha, 9beta-lanost-24-en-3beta-ol), beta-amyrin (olean-12-en-3beta-ol) and several aliphatic alcohols identified as the C18 to C30 members of the 1-alkanol homologous series. beta-Amyrin acetate was only isolated from Viscum cruciatum and was not found in Crataegus monogyna.     

Cytotoxic constituents from Brazilian red propolis and their structure-activity relationship

Several classes of flavonoids [flavanoids (1-10), flavonol (11), isoflavones (12-18), isoflavanones (19-22), isoflavans (23-26), chalcones (27-30), auronol (31), pterocarpans (32-37), 2-arylbenzofuran (38), and neoflavonoid (39)] and lignans (40-42) isolated from the MeOH extract of Brazilian red propolis were investigated for their cytotoxic activity against a panel of six different cancer cell lines including murine colon 26-L5 carcinoma, murine B16-BL6 melanoma, murine Lewis lung carcinoma, human lung A549 adenocarcinoma, human cervix HeLa adenocarcinoma, and human HT-1080 fibrosarcoma cell lines. Based on the observed results, structure-activity relationships were discussed. Among the tested compounds, 7-hydroxy-6-methoxyflavanone (3) exhibited the most potent activity against B16-BL6 (IC(50), 6.66microM), LLC (IC(50), 9.29microM), A549 (IC(50), 8.63microM), and HT-1080 (IC(50), 7.94microM) cancer cell lines, and mucronulatol (26) against LLC (IC(50), 8.38microM) and A549 (IC(50), 9.9microM) cancer cell lines. These activity data were comparable to those of the clinically used anticancer drugs, 5-fluorouracil and doxorubicin, against the tested cell lines, suggesting that 3 and 26 are the good candidates for future anticancer drug development.     

Cytotoxic constituents from Celastrus paniculatus induce apoptosis and autophagy in breast cancer cells

Celastrus paniculatus is a traditional medicinal plant with diverse pharmacological activities. To identify its bioactive constituents, three new β-dihydroagarofuranoid sesquiterpenes were isolated from the whole plant, of which the major constituent is (1α,2α,8β,9β)-1,8-bis(acetyloxy)-2,9-bis(benzoyloxy)-14-hydroxy-β-dihydroagarofuran. It was assessed for its antiproliferative activity, and it suppressed the viability of MCF-7 breast cancer cells with an IC₅₀ of 17 ± 1 μM. This growth inhibition was, in part, attributable to apoptosis. Moreover, this drug treatment led to LC3B-II accumulation, indicative of autophagy. Western blot analysis established its ability to target a broad range of signaling effectors related to survival and cell cycle progression, including Akt, NF-κB, p53, and MAP kinases. In addition, flow cytometry analysis indicates increased reactive oxygen species production in response to this compound. Taken together, these findings suggest a pleiotropic mode of mechanism that underlies the antiproliferative activity of this compound in MCF-7 breast cancer cells.     

Cytotoxic activity and constituents of the volatile oil from the roots of Patrinia scabra Bunge

The volatile oil from the roots of Patrinia scabra Bunge was isolated by steam distillation, and separated into four major fractions (Fr. A-D) by means of column chromatography. A total of 39 compounds (1-39) were identified by GC/MS analysis, and evaluated for their in vitro cytotoxic activities against human ovarian carcinoma cells (HO-8910) and human hepatoma cells (Bel-7402) (Table 1). Fr. A showed the strongest inhibitory effect on HO-8910 (IC50 = 21 microg/ml) and Bel-7402 cells (16 mcirog/ml), whereas Fr. B was the least active (>100 microg/ml). By comparison of the constituents of the four fractions, we assume that the cytotoxicity of the volatile oil of P. scabra is mainly due to the lignans and azulenes, rather than to caryophyllene oxide I (18). Our results suggest that the volatile oil of P. scabra possesses potent and tumor-specific cytotoxicity, and could serve as a possible candidate for future cancer chemotherapy.