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From camptothecin to vinblastine, plant alkaloids continue to capture the imagination of scientists as a valuable source of anticancer drugs. Given that they are also amongst the most common secondary metabolites encountered in plants, the number of alkaloid entities subjected to cytotoxicity evaluations now runs into several thousands. Interest in the plant family Amaryllidaceae has been persistent owing to the potent cytotoxic activities of several of its isoquinoline alkaloid principles. This survey is an indepth account of such properties discernible for tazettine alkaloids belonging to the minor alkaloid groups of the Amaryllidaceae. Eleven of such compounds have up to now been screened against around 50 cancer cell lines which may be classified into nearly 20 different types of cancers. Although the activities in most instances were moderate to mild, notable responses were observed against some leukemia, adenocarcinoma, lymphoma and glioblastoma cell lines. In fact, pretazettine (ED50 0.3 μg/mL) was amongst the most potent of all Amaryllidaceae alkaloids screened against the human Molt4 T-lymphoma cell line. To most accounts, the parent compounds (such as tazettine and pretazettine) with their distinct ring systems and substitution patterns exhibit the best activities, offering little space for structural adjustments via semi-synthetic operations. Several avenues have been probed in attempts to elucidate the mechanisms by which tazettine alkaloids manifest their cytotoxic effects including, inhibition of protein synthesis, apoptosis and efflux pump interactions, the first of which to date offers the most profound insights.

There are subtle mechanisms at work in nature to maintain a balance in the interactions between plants and animals. The production of secondary metabolites is one of the key strategies utilized by plants to minimize their over-exploitation. The ‘lily borer’ moth Brithys crini poses a considerable challenge to Amaryllidaceae plants owing to the devestation it can cause during the larval stage of its development. This, despite the fact that the Amaryllidaceae is richly endowed with an assortment of isoquinoline alkaloid constituents which exhibit a diverse array of biological properties, particularly cytotoxicity-related effects. In this study, laboratory-maintained larvae of B. crini were periodically fed fresh leaves of Crinum moorei during the September to November infestation period in Pietermaritzburg, South Africa. Solvent extracts of the plant leaves, moth larvae and larvae excrement material were then prepared and subjected to HPLC and LC–MS analyses. The presence of several alkaloids, including cherylline and ambelline, in all three extracts was ratified via HR-MS and NMR analyses. The identification of ambelline is noteworthy since it has not been reported in previous studies of C. moorei. Toxicity related criteria are also considered based on the present detection of alkaloids in B. crini larvae material, as well as precedence for their association with other known insect predators of the Amaryllidaceae.

Malaria is responsible for majority of the morbidity and mortality statistics reflected by tropical diseases. Whilst effectively managed in most parts of the globe, it remains a scourge on the African continent where most cases of the disease are diagnosed annually. Plants have played a leading role as a source of malarial drugs which continue to dominate the clinical landscape today. Most if not all of these discoveries have as their basis evidence which can be traced back to traditional medicine. There is likewise precedence for the use of Amaryllidaceae plants in traditional medicinal approaches towards malaria. The chief phytochemical principles of the Amaryllidaceae are its isoquinoline alkaloids which are responsible for its diverse biological properties. These alkaloids may be divided into major and minor groups based on their distinguishing structural features as well as their natural abundance and distribution in the family. Whilst much has been written about the biological and chemical properties of the major alkaloid groups of the Amaryllidaceae, relatively little is known or understood about its minor alkaloid groups. This review focuses on the antiplasmodial activities described in the literature for the minor alkaloid group members of the Amaryllidaceae against various strains of the malarial pathogen Plasmodium falciparum . Three database platforms (Google Scholar, SciFinder and Scopus) were utilized for the literature search. Articles were accessed from journals licensed to the University of KwaZulu-Natal, or directly via the respective corresponding authors. Also considered are structural elements of these alkaloids which may be used to explain such activities as well as to provide a foundation in attempts to modulate activities. In addition, evidence is provided on the molecular basis to these effects which could guide efforts in drug discovery.

Over 600 alkaloids have to date been identified in the plant family Amaryllidaceae. These have been arranged into as many as 15 different groups based on their characteristic structural features. The vast majority of studies on the biological properties of Amaryllidaceae alkaloids have probed their anticancer potential. While most efforts have focused on the major alkaloid groups, the volume and diversity afforded by the minor alkaloid groups have promoted their usefulness as targets for cancer cell line screening purposes. This survey is an in-depth review of such activities described for around 90 representatives from 10 minor alkaloid groups of the Amaryllidaceae. These have been evaluated against over 60 cell lines categorized into 18 different types of cancer. The montanine and cripowellin groups were identified as the most potent, with some in the latter demonstrating low nanomolar level antiproliferative activities. Despite their challenging molecular architectures, the minor alkaloid groups have allowed for facile adjustments to be made to their structures, thereby altering the size, geometry, and electronics of the targets available for structure-activity relationship studies. Nevertheless, it was seen with a regular frequency that the parent alkaloids were better cytotoxic agents than the corresponding semisynthetic derivatives. There has also been significant interest in how the minor alkaloid groups manifest their effects in cancer cells. Among the various targets and pathways in which they were seen to mediate, their ability to induce apoptosis in cancer cells is most appealing.

Protozoan-borne diseases are prominent amongst diseases caused by parasites. Given their alarming morbidity and mortality statistics, there is ever growing interest in new therapies against these diseases. Whilst synthetic drugs such as benznidazole and melarsoprol have had a profound influence on the clinical setup, there has been significant interest in the phytochemical platform to also deliver such drug candidates. The plant family Amaryllidaceae is recognizable for its isoquinoline alkaloids, which exhibit attractive molecular architectures and interesting biological properties. This survey focuses on the antiprotozoal activities of 73 of such substances described in 18 different species of the Amaryllidaceae. Of these, 2-O-acetyllycorine was identified as the most potent (IC50 0.15 μg/mL against Trypansoma brucei brucei). Also considered are structure-activity relationships which have served to modulate activities, as well as the plausible mechanisms that underpin these effects and afford insight to the Amaryllidaceae alkaloid antiprotozoal pharmacophore.

The spread of malaria is thought to have followed human expansion out of Africa some 60 – 80 thousand years ago. With its prevalence in pantropical countries of the world and epicenter localized in Africa, malaria is now considered an unnecessary burden to overworked and under-resourced healthcare structures. Plants have long afforded a fertile hunting ground for the search and identification of structurally diverse antimalarial agents, such as quinine and artemisinin. This survey examines the antiparasitic properties of the family Amaryllidaceae via the antiplasmodial activities demonstrated for its lycorane alkaloid principles. Of these, 24 were natural compounds identified in 20 species from 11 genera of the Amaryllidaceae family, whilst the remaining 28 were synthetically derived entities based on the lycorane skeleton. These were screened against ten different strains of the malarial parasite Plasmodium falciparum, wherein the parent compound lycorine was shown to be the most potent with an IC50 of 0.029 µg/mL in the FCR-3 strain seen to be the best. Structure-activity relationship studies revealed that good activities were detectable across both the natural compounds as well as the synthetically accessed derivatives. Such studies also highlighted that there are several inherent structural features that define the lycorane alkaloid antiplasmodial pharmacophore, such as the nature of its ring systems and properties of its substituents. Mechanistically, a limited number of studies confirmed that lycorane alkaloids manifest their action by targeting enzymes associated with the plasmodial FAS-II biosynthetic pathways. Overall, these alkaloids have provided useful, convenient, and accessible scaffolds for antimalarial-based drug discovery.

Malaria is prevalent in tropical and subtropical regions of the globe. With over 200 million cases reported annually, particularly in sub-Saharan Africa, it is an unnecessary burden to already overworked and ailing healthcare structures. Traditional medicine (TM) remains vibrant in most of these regions wherein plants often serve as the first line of defense against malaria. Given this fact as well as the successes elsewhere of therapies such as Artemisia annua emanating from evidence-based TM, interest in plants as a source of new antimalarial drugs has been rejuvenated. The bulbous plant family Amaryllidaceae is recognized for its structurally-diverse alkaloid constituents which exhibit interesting biological properties. This review focuses on the in vitro activities demonstrated by its crinane alkaloids against various strains of the malaria-causing parasite Plasmodium falciparum. The survey embraces the twelve genera of the Amaryllidaceae whose nineteen representative species have been examined for antiplasmodial crinane alkaloid principles. A total of seventy-two compounds were screened against nine strains of P. falciparum, with the α-crinanes reflecting better overall activities than their corresponding β-crinane subgroup congeners. In terms of potency, an ED50 of 0.14 μg/mL (for augustine in the D-6 strain) and IC50 of 0.35 μg/mL (for haemanthidine in the K1 strain) were the lowest activity indices observed. Structure-activity relationship studies afforded useful insight on the antiplasmodial pharmacophore and the features supporting its efficacy. Overall, crinane alkaloids have provided a useful platform for the study of antiplasmodial effects, not only in terms of potency but also in terms of structural diversity.

The birth, growth, proliferation and death of cells involve a rigorous and continuous process in place to ensure the survival of living organisms. The cell cycle prevails at the core of this process to facilitate the division of a parent cell as well as the duplication of its genetic matter. Although checkpoints exist to steer the course of a cell from one phase to the other, malfunctions at any point of the four active phases of the cell cycle can have detrimental effects. Cancer is thought to be a consequence of such a malfunction in the cell cycle which endows a cell with enhanced replicative potential, immunity to anti-growth signals and the ability to evade apoptosis. This characteristic has been exploited in cancer chemotherapy since a significant number of anticancer drugs manifest their action via cell cycle modulatory effects. The plant family Amaryllidaceae is distinguished for its alkaloid principles which exhibit potent (at the sub-nanomolar level in some cases) and cell line specific antiproliferative activities, with apoptosis induction a key feature of these properties. As a consequence there has been sustained interest in these chemical entities as a source of new anticancer drugs. This has been matched by the large body of work that has emerged over the past two decades addressing their cytotoxic potential, establishing a structure-activity relationship basis as well as probing their mode of action. This review focuses on studies which highlight how Amaryllidaceae alkaloids modulate the cell cycle of cancer cells.

Globalization, the modern lifestyle, immuno-suppressive agents, invasive surgical procedures, the loss of efficacies of existing drugs, and multidrug resistance are some of the factors used to explain the rise in fungal infections in recent years. Significant advances have been made in attempts to replace existing antifungal schedules, especially with synthetic targets. The identification of other platforms for drug discovery is now entrenched in research programs across the globe. Plants offer significant benefits owing to their numerical superiority, exceedingly broad chemical basis and appealing sustainability characteristics. Furthermore, plants have a long and rich historical association with traditional approaches towards fungal diseases. These have in numerous instances served as markers in the bioassay-guided identification of the active constituents. Although the plant family Amaryllidaceae is conventionally associated with cancer and motor-neuron disease chemotherapies, around 30 of its species have been examined for antifungal activities with microgram per millilitre inhibitory activities detected in several instances. This review focuses on the nearly 40 constituents from the family, mainly isoquinoline alkaloids, which have been screened against around 50 fungal pathogens. Encouragingly, microgram per millilitre growth inhibitory activities were applicable for several of the compounds with a minimum inhibitory concentration of 4 μg/ml seen to be the lowest.

Plants have long served as a first line of defense response to malaria. They have also spawned several classes of antimalarial drugs such as quinine and artemisinin. However, most if not all of these drugs have succumbed to multidrug resistance, thus reigniting interest in the identification of novel chemotherapies against this parasitic disease. The starting point for many of such endeavors lies with the plants themselves whose extracts have served as herbal remedies, which originate from traditional medicine (TM). Several species of the Amaryllidaceae have been shown to have such functions in TM. This survey examines those plants of the family, which have hitherto been examined for antiplasmodial effects against the malarial parasite Plasmodium falciparum. Also considered are the alkaloid constituents of these plants, which have demonstrated activities against various strains of the pathogen. Particular emphasis is made on those plants which both demonstrate such activity as well as have a place in traditional therapies for malaria.

article i nfo The "large sour plum" tree Ximenia caffra Sond. (Olacaceae) is the only African representative of the genus Ximenia L., with a distribution covering East Africa, from Tanzania in the north to South Africa, as well as parts of Botswana and Namibia. It has many uses in traditional medicine, including treatment of wounds and infections as well as diarrhea, which have been verified through various pharmacological studies. Fur- thermore, the plant is also known for its nutritional and cosmetic value. Its edible fruits are known to be high in protein, potassium and vitamin C, while the seed oil, also referred to as "Ximenia oil" is rich in long chain unsaturated fatty acids and finds use as a domestic biofuel, with characteristics amenable to cosmetic development as topical applicants. Extracts of the plants are also widely used for treating sexually transmit- ted infections (STIs), which has been verified through ethnobotanical surveys and pharmacological screens. Based on these observations, X. caffra var. caffra was examined for its phytochemical composition and activity against the gonorrheal pathogen Neisseria gonorrhoeae. Initially, the leaf ethanolic extract was seen to be ac- tive (43.9% inhibition). The DCM partition of this extract (with 78.8% inhibition) was subjected to bioassay guided fractionation leading to the identification of the bisnorsesquiterpene vomifoliol which exhibited sig- nificant activity (63.1%) against N. gonorrhoeae.

West Valley Demonstration Project (WVDP) Annual Site Environmental Report (ASER) for Calendar Year 2014. The report, prepared for the U.S. Department of Energy West Valley Demonstration Project office (DOE-WVDP), summarizes the environmental protection program at the WVDP for calendar year (CY) 2014. Monitoring and surveillance of the facilities used by the DOE are conducted to verify protection of public health and safety and the environment. The report is a key component of DOE’s effort to keep the public informed of environmental conditions at the WVDP. The quality assurance protocols applied to the environmental monitoring program ensure the validity and accuracy of the monitoring data. In addition to demonstrating compliance with environmental laws, regulations, and directives, evaluation of data collected in 2014 continued to indicate that WVDP activities pose no threat to public health or safety, or to the environment.

Ethnopharmacological relevance Boophone disticha (Amaryllidaceae) is one of the most common bulbous plants used for medicinal purposes by the indigenous people of southern Africa. Its use as a narcotic substance by the Khoi/San tribes has been known for several centuries, while the Sotho, Xhosa and Zulu people are known to use the plant to treat a host of ailments, including inflammation, wounds, gynaecological conditions and psychosis. Aim of the study Much of the pharmacological work on the plant, such as affinity to the serotonin transporter, has been based on its reputed usage for narcotic purposes. However, its widespread use to treat wounds and infections has not been linked to a specific chemical entity. In this regard, Boophone disticha was here examined for its phytochemical composition which could shed light on the use of the plant for such purposes. Materials and methods The known crinane alkaloids buphanidrine and distichamine were isolated via column chromatography of the ethanolic extract of bulbs of Boophone disticha. Structural details of the compounds were determined by high field 2D NMR and mass spectroscopic techniques. Microbial activity against selected Gram-positive and Gram-negative bacteria was ascertained according to the micro-dilution assay. Results Both buphanidrine and distichamine were uncovered as novel, broad spectrum moderately active, antibacterial agents with the best MIC value detected at 0.063 mg/ml for Staphylococcus aureus, Escherichia coli and Klebsiella pneumoniae. MIC values for Bacillus subtilis were two-fold less than that observed for the other three bacteria, suggesting that the extract and pure compounds were selective in their interaction with the bacterial pathogens. Conclusion Phytochemical investigation of Boophone disticha has led to the identification of two known crinanes, buphanidrine and distichamine. Based on the reputed traditional use of the plant for wounds and infections, both compounds were screened for antibacterial activity which revealed them to be novel, broad spectrum antibacterial agents with the best MIC value set at 0.063 mg/ml. Their close structural similarity may have bearing on their similar activity profiles.

seco-Derivatives of the anticancer agent pancratistatin bearing the 2S,3S,4S,5S configuration were accessed via a novel, highly diastereoselective anti-aldol reaction. Structure–activity relationships reveal important insights into the seco-pancratistatin pharmacophore as a potent and selective inhibitor of human cytochrome P450 3A4 (CYP3A4), and highlight features of concern in advancing a potent, selective anticancer agent in the pancratistatin series.

The growth in demand for cosmetic, graft and organ transplant surgical procedures, the increased use of antineoplastic and immunosuppressive agents, as well as multidrug resistance are some of the factors responsible for the marked rise in fungal infection rates in recent years. Consequently, there have been renewed calls from both the public and private sectors for new and improved drug targets to replace existing antifungal therapies, many of which have been in clinical circulation for several decades. Plants select themselves in such endeavors owing to their superior numbers and vast chemical diversities. With this as a backdrop, this survey examines the antifungal activities of Amaryllidaceae plant extracts against various fungal pathogens. Good growth inhibitory activities (MICs

Cells cultured from Alzheimer disease leptomeninges or skin were grafted into the cortex of adult thymectomized rats. At 3 days post-implant, plaque-like aggregates were found in the cortex, corpus callosum, septum and caudate nucleus. These structures were immunopositive for human amyloid precursor protein (APP), human amyloid beta peptide (Aβ), cathepsin D, apolipoprotein E and ubiquitin. Aberrant tau + neurites, reactive astrocytes and microglia were associated with many aggregates. Although birefringent amyloid occupied the central area of most aggregates, these structures had disappeared by l month post-implant. Aβ and APP produced by grafted non-neural human cells can penetrate rat brain and form plaque-like structures, which can be effectively cleared by the rat.

The plant family Amaryllidaceae is well-known for its unique alkaloid constituents, which exhibit a wide range of biological activities. Its representative, Amaryllis belladonna, has a geographical distribution covering mainly southern Africa, where it has significant usage in the traditional medicine of the native people. In this study, A. belladonna samples collected in Brazil were examined for alkaloid content. Alkaloid profiles of A. belladonna bulbs were generated by a combination of chromatographic, spectroscopic and spectrometric methods, including GC–MS and 2D NMR. In vitro screening against four different parasitic protozoa (Trypanosoma cruzi, T. brucei rhodesiense, Leishmania donovani and Plasmodium falciparum) was carried out using the A. belladonna crude methanol extract, as well as three of its alkaloid isolates. Twenty-six different Amaryllidaceae alkaloids were identified in the A. belladonna bulb samples, and three of them were isolated. Evidence for their respective biosynthetic pathways was afforded via their mass-spectral fragmentation data. Improved data for 1-O-acetylcaranine was provided by 2D NMR experiments, together with new 1H-NMR data for buphanamine. The crude extract and 3-O-acetylhamayne exhibited good antiprotozoal activity in vitro, although both with a high cytotoxic index.

The remediation of infectious diseases is an ongoing concern in healthcare structures due to the continued loss of efficacies of existing schedules and, in particular, the poignant threat of multidrug resistance. In the search for new therapies plants have emerged as an attractive option owing to their vast chemical resources. Allied to this feature is the widespread use of plants in traditional approaches towards infectious diseases. As far as the family Amaryllidaceae is concerned, around fifty of its members are identifiable with such distinctive functions in traditional medicine. This review examines the in vitro antibacterial activities of its plant extracts and sheds light on instances where these are corroborative of the traditional usage.

We determined whether the expression of matrix metalloproteinases (MMP) and tissue inhibitors of MMPs (TIMP) in murine macrophages is regulated by the novel synthetic bacterial lipopeptide JBT 3002. Multilamellar liposomes (MLV) encapsulating JBT 3002 (MLV-JBT 3002) stimulated the production of 72-kDa and 92-kDa (gelatinase A and B) type IV collagenase and inhibited the production of murine metalloelastase (MME) in a dose-dependent manner in murine peritoneal macrophages. MLV-JBT 3002 also induced production of TIMP-1. MLV-JBT 3002 did not induce collagenase production in tumor cells. Priming murine macrophages with interferon-gamma (IFN-gamma) inhibited JBT 3002-stimulated production of both MMP-9 and MMP-2 and further inhibited production of MME by a mechanism involving nitric oxide (NO). This conclusion is based on data showing that IFN-gamma failed to inhibit production of MMP in the presence of L-methyl arginine or in macrophages from inducible nitric oxide synthase knockout mice. These data suggest that JBT 3002 differentially regulates the production of various MMPs and TIMP in macrophages.

Cell membranes contain numerous species of glycosphingolipids (GSL) and glycerophospholipids. Changes in the surface expression of these moieties that accompany malignant transformation are potential targets for immune therapies. There is increasing evidence that tumour specificity resides in the carbohydrate composition and topography of gangliosides and in the asymmetric distribution of phospholipids in the bilayer membrane. However, since these epitopes are not antigenic, circumvention of immunological tolerance to these ‘self antigens’ is required to generate an effective immune response. New methodologies accomplish this by coupling these hapten-like lipid epitopes to immunogenic protein carriers. Indeed, the generation of immune responses to endogenous lipid antigens occurs in several autoimmune syndromes and may serve as natural models for therapeutic immune intervention that influence pathways critical to tumour angiogenesis, proliferation and apoptosis.

We determined whether the angiogenesis and growth of murine colon carcinomas growing in the wall of the cecum is dependent on infiltrating leukocytes. Syngeneic BALB/c or SCID mice were treated with a myelosuppressive, maximally tolerated dose of doxorubicin. Parental or multidrug resistant CT-26 colon carcinoma cells were implanted into the cecal wall 3 days after the second intravenous injection of doxorubicin. Control mice developed large, well-vascularized tumors, whereas doxorubicin-pretreated mice did not. Intravenous injection of spleen cells from normal BALB/c or SCID mice one day prior to tumor cell implantation reversed the decreased vascularity and tumorigenicity. The production of proangiogenic molecules and microvessel density in tumors directly correlated with the number of infiltrating leukocytes, suggesting that tumor-infiltrating leukocytes are essential to angiogenesis of murine colon carcinomas.

Aim of this study was to develop and characterize an applicable in vivo model to investigate angiogenesis of human gliomas. An established glioblastoma spheroid model was used to investigate the neovascularization of a standardized avascular solid tumor mass. Spheroids of two human glioma cell lines were labeled with an in vivo fluorescent dye. Single spheroids were implanted into the cortex of athymic rats. After 1, 3, 7, 14, and 21 days, brain sections containing the spheroid were immunostained for endothelial cells or vascular endothelial growth factor (VEGF). The dye-stained glioma spheroid and the endothelial cells were visualized by confocal microscopy. Two distinct mechanisms of tumor vascularization could be observed. (1) "Classical" angiogenesis with new vessels sprouting from existing host vessels into the spheroid was seen. (2) Individual endothelial cells were found to migrate towards and into the center of the spheroid where they coalesced to form new vessels. This process occurred as early as 24 hr after spheroid implantation. Spheroid vascularization was accompanied by an increase of VEGF expression, which peaked 7 days after implantation and returned to normal patterns by 14-21 days. Besides the "classical" angiogenesis by angiogenic blood vessels, the recruitment of individual endothelial cells seems to be an additional mechanism in early glioma vascularization. Our model proves to be a reliable, reproducible system to study in vivo angiogenesis of human gliomas.

Cell adhesion receptors of the integrin superfamily, CD44, and adhesion receptors of the immunoglobulin superfamily are expressed by high-grade astrocytic tumors of the central nervous system. These receptors are critical for the invasion of these tumors in the nervous system. Glioma cells utilize these receptors to adhere to and migrate along the components of the extracellular matrix, which is uniquely distributed and regulated within the brain and the spinal cord. For this reason, glioma cell invasion into the adjacent brain tissue is dependent on the interaction of glioma cells with the extracellular matrix. The receptor-ECM component interaction is discussed, focusing on the role of cell adhesion molecules of the integrin family and CD44 in glioma cell adhesion and invasion.

Although humoral responses to Borrelia burgdorferi (Bb) have been shown to be protective in some animal models of Lyme disease, the role of T cells in this disease is less well understood. This work describes three Bb-specific T cell lines that prevent disease progression in syngeneic mice. The T cell lines were generated in C3H mice immunized with Bb in complete Freund's adjuvant. All lines were Bb-specific, CD4+, TCRαβ+, and they proliferated and produced interferon-γ and interleukin-2 on stimulation with Bb. Injection of the cell lines into naive C3H recipients significantly reduced the number of organisms recoverable from the blood and tissues of infected mice and protected them from developing Bb-induced periarthritis. These studies demonstrated that Th1 cells can confer resistance to Bb infection in susceptible mice and suggested that the timing of this T cell response may be critical for determining disease outcome.

Rapid evaluation of new cytotoxic agents and biological response modifiers for therapy of cancer and elucidation of their mechanisms of action require the use of relevant animal models. It is well established that the faithful reproduction of the tumor microenvironment that allows the emergence of subpopulations of tumor cells with the biological and metastatic properties observed in clinical cancer occurs with orthotopic tumor models (transplantable and transgenic). This review summarizes the evidence that phenotypic properties of metastatic cells are governed by the expression of genes that are regulated by interaction with the relevant organ environment. While ectopic models of cancer allow rapid screening of new compounds and transgenic models afford opportunities to study early cellular and molecular events in tumor progression and metastasis, orthotopic transplantation of tumor cells remains an affordable, reproducible and reliable methodology for the study of organ-specific determinants of the biology and therapy of cancer.

The challenge of disease and death caused by infectious diseases is strikingly apparent in both developed and developing nations around the world, with developing countries being the most affected. As infectious diseases evolve and pathogens develop resistance to existing pharmaceuticals, the search for new novel leads, possibly with different modes of action, against fungal, bacterial, and viral diseases has intensified in recent years. To most of the African population, the use of medicinal plants to combat these challenges forms an integral component of their culture and hence a prominent characteristic. To this extent, several species have been subjected to different pharmacological screening techniques using different pathological strains. As a result, varied ranges of bioactivities have been reported for a number of species, different plant parts, and even geographical location and season. We present here the best reported antimicrobial activities of “Africa’s top 50 medicinal plants.”

A hexane extract of the wood of Dysoxylum muelleri has yielded 3α-cinnamoyl glabretal, 3α-benzoyl glabretal, 21,24-epoxy-23α,25-dihydroxy-4α,4β,8β-trimethyl-14,18-cyclo-5α,13α,14α,17α-cholestan-3α-cinnamoyl-7α-yl acetate, 21,24-epoxy,23α,25-dihydroxy-4α,4β,8β-trimethyl-14,18-cyclo-5α,13α,14α,17α-cholestan-3α-benzoyl-7α-yl acetate; 21,23-epoxy-21,24,25-trihydroxy-4α,4β,8β-trimethyl-14,18-cyclo-5α,13α,14α,17α-cholestan-3α-cinnamoyl-7α-yl acetate and 21,23-epoxy-21,24,25-trihydroxy-4α,4β,8β-trimethyl-14,18-cyclo-5α,13α,14α,17α-cholestan-3α-benzoyl-7α-yl acetate. A hexane extract of the bark yielded 6α-acetoxy-obacunone acetate.

The following series of experiments explores the post-xenografting differentiation of a naturally occurring, non-neuronal cell cultured from the leptomeninges of an 84-year-old woman. In culture, flat process-bearing human cells from the leptomeninges were positive for GFAP and 200 kDa neurofilament protein (negative for 68, 160 kDa neurofilament protein). The C3 spinal cord was exposed in 30 adult athymic rats. The hindlimb dorsal columns were transected at C3 and the nerve fibers aspirated to form a pocket, into which 10(6) fast blue-labeled, human leptomeningeal-derived cells were placed. The C3 spinal cord was studied immunohistochemically over 60 days. Three days later the dorsal horn contained fast blue-GFAP-positive astrocyte-like cells that were negative for neurofilament protein. By 7 days, large, process-bearing, fast blue-GFAP-positive (neurofilament protein-negative), astrocyte-like cells joined the native astrocytes of the pia-glia membrane and were in the gray matter of the spinal cord. Some of these astrocyte-like cells were also positive for the human specific histocompatibility complex, HLADR. These data extend the age, species and tissue of origin for pluripotential cells for CNS transplantation.

Astrocytes appear to be excluded from blood vessels. In order to test this observation, pial blood vessels were seeded upon cultures of purified E14 fetal astrocytes. One to seven days later co-cultures were immunohistochemically stained for laminin and fibronectin. Confocal microscopy revealed that laminin-positive cultured astrocytes migrated from the coverslip to and on to the surface of the blood vessels. The fetal astrocytes migrated along the basement membrane but did not enter the blood vessel. Viable (live) basement membrane is a barrier to astrocyte intravasation and is a pathway for astrocyte migration. Published by Elsevier Science Ltd.

Purpose: These studies were designed to develop an orthotopic model for human bladder cancer and to isolate variant metastatic cell lines.Materials and Methods: The human bladder cancer cell line 253J was implanted into the muscular wall of the bladder of athymic nude mice. By in vivo recycling, we selected for 2 variant cell lines: 253J B-V, a bladder line isolated after 5 serial passages in the bladder, and 253J lung-IV, established from a lung tumor nodule that was recycled through the bladder.Results: These 2 cell lines showed enhanced tumorigenicity, as measured by a decreased latent period, and rapid growth as compared with the parental cell line. Moreover, orthotopic implantation of these cell lines resulted in metastasis to the lungs. These in vivo-selected, metastatic cell lines exhibited unique karyotypic alterations, increased anchorage-independent growth, overexpression of basic fibroblast growth factor, altered expression of adhesion molecules and the ability to migrate through Matrig...

Glioblastoma is very rarely found outside the central nervous system. The ability of rat C6 glioblastoma cells to intravasate into central nervous system and pial blood vessels is tested using a rat homografting model and two in vitro models. In vivo, scanning electron microscopy demonstrates that upon grafting C6 cells into implantation pockets in rat cortex, blood vessels can be spared in large digestion cysts formed in host brain parenchyma. Immunocytochemistry of the grafted rat cortex reveals that the glioblastoma cells are upon the blood vessel basement membrane, surrounded by the extracellular matrix material, fibronectin. The endothelial cells of the blood vessel are inside the laminin and fibronectin, and there were areas of endothelial cell hyperplasia. C6 cells are not observed inside blood vessels. In vitro, C6 cell cultures seeded with blood vessels from fresh rat pia exhibit the same relationship of the C6 glioblastoma cells to the blood vessel as those in the other models. The C6 cells migrate upon the pial blood vessel basement membrane but do not intravasate into the blood vessel. To ascertain whether structure and components of the blood vessel basement membrane are important factors in glioblastoma cell exclusion from blood vessels, C6 cells are seeded upon artificial basement membrane hydrated gel wafers. C6 cells migrate into the artificial basement membrane gel wafer by 1 day after seeding. These data indicate that glioblastoma cells are confined to the central nervous system by an inability to pass through vital basement membrane.

The antiproliferative effect of interferon alpha (IFN-alpha) against cultured 253J human bladder tumour cells was enhanced when IFN-alpha was encapsulated into multilamellar phospholipid liposomes (MLV). Moreover, significant cytostasis of a variant 253J subline (253J alpha R, resistant to the antiproliferative effect of IFN-alpha), could be achieved by delivery of IFN-alpha contained in liposomes. Although the two cell lines have the same number and affinity of cell receptors for IFN-alpha, the 253J alpha R cells did not down-regulate receptors as observed for the IFN-sensitive 253J cells. The IFN-response genes, 2'-5' oligosynthetase and gene 6-16 were equally induced in both cell lines following incubation of the cells with either free IFN-alpha or liposome-encapsulated IFN-alpha. Incorporation of radiolabelled IFN-alpha into cells by liposomes was independent of the status of IFN-receptors (the receptors being either occupied or down-regulated). These observations are consistent with the hypothesis that the antiproliferative effects of IFN-alpha against 253J and 253J alpha R cells may be mediated by internalization of IFN-alpha.

The therapy of cancer is, in reality, the design of therapeutic strategies for therapy of metastatic disease. Metastases consist of unique subpopulations of tumor cells that are derived from the primary tumor, colonize distant target organs, and are able to subvert host immune responses, establish necessary angiogenesis, and obtain a sufficient nutrient supply while evolving to become autonomous from homeostatic mechanisms that function within normal, differentiated tissues. Attempts at eradication of metastases by conventional therapies have generally been unsuccessful due to genetic instability and heterogeneity of metastatic tumors; these properties lead to the emergence of tumor cells that are resistant to most conventional treatments. It may be possible to circumvent this heterogeneity by the activation of tissue macrophages to the tumoricidal state. Activated macrophages are able to kill tumor cells while sparing normal tissues, and efficient activation can be achieved by encapsulation of synthetic muramyl tripeptide analogues into multilamellar vesicles composed of phospholipids. Systemic administration of these liposome-encapsulated compounds leads to tumoricidal activation of alveolar and peritoneal macrophages and eradication of established tumor metastasis in numerous animal tumor models, and this form of therapy is enhanced by combination with parenteral administration of cytokines. Phase III clinical trials of recurrent osteosarcoma are currently in progress. Modulation of the tumor microenvironment by activated macrophages may prove to be an additional modality in treatment strategies that combine the use of biological response modifiers with conventional therapies.

A series of saccharin derivatives I has been synthesized and evaluated for their inhibitory activity toward human leukocyte elastase and cathepsin G. Most of the compounds were found to be efficient and time-dependent inhibitors of elastase. Inactivated elastase was found to regain its activity almost fully after 24 h (80-90% activity) and the half-lives of reactivation ranged between 12-15 h. Addition of hydroxylamine to fully-inactivated enzyme led to rapid and complete recovery of enzymatic activity. A tentative mechanism of action is proposed on the basis of biochemical and model studies.

A series of 3-( alkylthio )-N- hydroxysuccinimide derivatives was synthesized and their inhibitory activity towards human leukocyte elastase (HLE) was investigated. The interaction of the compounds having a 3-alkylthioether side chain (compounds 1 and 2) with HLE was found to involve rapid acylation of the enzyme, followed by total regain of enzymatic activity within 3 h. Interestingly, compounds 3–8, having an oxidized thioether side chain, were found to be highly effective, time-dependent, irreversible inhibitors of the enzyme. The k obs /I values for compounds 3–8 ranged between 890 and 24 000 M−1 s−1. These findings demonstrate that, unlike the physiological inhibitor of HLE (alpha-1-proteinase inhibitor), which is inactivated upon oxidation, low-molecular-weight compounds retain and/or show enhanced inhibitory activity towards HLE upon oxidation of the thioether side chain and lay the groundwork for the development of compounds that embody proteinase inhibitory and antioxidant activity.

We determined whether the intravenous administration of multilamellar vesicle liposomes (MLV) containing a lipopeptide analogue of a fragment from the cell wall of gram-negative bacteria (CGP 31 362) can render BALB/c mouse alveolar macrophages tumoricidal in situ and reduce the incidence of spontaneous lung metastasis of syngeneic renal carcinoma (RENCA) cells. Alveolar macrophages (a) incubated in vitro with MLV containing CGP 31 362 (MLV-31 362) and (b) harvested from mice injected i.v. with MLV-31 362 were rendered cytotoxic against the RENCA cells. Maximum cytotoxic activity of the macrophages was induced by injecting 5 µmol MLV consisting of 250 mg phospholipids and 0.5 mg CGP 31 362. The single i.v. injection of 5 µmol MLV-31 362 produced activation of macrophages that lasted for up to 4 days. Repeated i. v. injections of MLV-31 362 produced a continuous antitumor activity in alveolar macrophages. To study the lipopeptide's effects on metastasis, we injected the left kidneys of BALB/c mice with RENCA cells. The kidney with growing tumor was resected 10 days later and, after a further 2 days, groups of mice were injected i.v. with MLV-31 362 or with MLV-HBSS (twice weekly for 3 weeks). Treatment with MLV-31 362 significantly decreased the median number of spontaneous lung metastases. These data demonstrate that the systemic administration of MLV-31 362 can activate murine lung macrophages in situ and reduce the incidence of spontaneous RENCA lung metastases.

Cultured C6 glioma cells were prelabeled with the plant lectin Phaseolus vulgaris leuco-agglutinin (PHAL) and grafted as a cell suspension (10(6) cells in 5.0 microliters) into freshly made cortical implantation pockets in adult host rats. Animals were killed 1-21 days post-implantation (DPI). The brains were removed, dehydrated, embedded in paraffin and sectioned at 8 microns. Paraffin sections were processed for light level immunofluorescent double labeling for PHAL, a marker for graft derived cells, and glial fibrillary acidic protein (GFAP), a specific marker for C6 glioma cells and astrocytes. Cells positive for both PHAL and GFAP were graft-derived C6 cells. By 7 DPI a large mass developed which extended above the surface of the brain and invaded (displacement of host tissue by a cell mass) the host parenchyma. This mass increased in size over the next 14 days. The invading tumor mass contained double labeled cells at all time periods examined. In addition to the invasion process, grafted C6 cells spread through the host parenchyma by migration (movement of single cells). Individual graft-derived C6 (GFAP/PHAL positive) cells migrated into host cortex surrounding the implantation pocket, corpus callosum ventral to the implantation pocket, ipsilateral internal capsule and bilaterally in the habenula.

In a 'double blind' study, 2 series of adult rats were trained to traverse a narrow bar or a horizontal ladder for a water reward. Hindlimb placement (measured as hindlimb foot slips) of the subjects trained on the narrow platform was ranked. The subjects traversing the ladder were videotaped and the number of hindlimb slips counted. After reaching criterion (10 complete traverses on each of 2 consecutive days), all animals had the fasciculus gracilis (FG) of the third cervical spinal cord segment (C3) aspirated to sever hindlimb dorsal column afferents. After aspiration of C3FG the subjects were randomly placed in an aspiration-only (controls) or aspiration + graft group. All grafts were prelabeled with the plant lectin Phaseolus vulgaris leucoagglutinin (PHAL) as a graft-derived cell marker. The grafts were either unoriented whole pieces of E14 fetal spinal cord or 105 purified, cultured, E14 fetal spinal cord astrocytes. Subjects were tested at intervals over 90 days. Aspiration of C3FG and a graft of whole pieces of E14 fetal spinal cord resulted in a statistically significant improvement in hindlimb placement at 21 and 90 days (P < 0.05) when compared to controls. In contrast, animals with cultured, purified, E14 fetal spinal cord astrocyte grafts had significantly worse (P < 0.05) hindlimb placement than controls. Immunohistochemical double staining for PHAL and glial fibrillary acidic protein in the same cell showed that astrocytes from both types of grafts migrated to the nucleus gracilis (NG) of the medulla of the host. The grafted fetal astrocytes from the whole piece grafts prevented denervation atrophy of the host NG neurons, whereas cultured grafted fetal astrocytes did not demonstrate this effect. After grafting donor tissue that contained astrocytes into the injured spinal cord there were two accompanying classes of astrocytes. One class derived from whole piece, E14, fetal spinal cord grafts migrated to the NG of the host, prevented atrophy of host NG cluster and interneurons, and improved hindlimb placement. The other class, derived from cultures of E14 fetal spinal cord astrocytes, migrated to the NG of the host, failed to maintain the size of cluster neurons and interneurons of the host NG, and resulted in a greater hindlimb placement deficit when compared to controls. These data suggest that improvement of hindlimb placement due to graft-derived fetal astrocytes in injured host spinal cord was due to the ability of the astrocytes to maintain host neurons and neuronal networks.

The total synthesis of fully functionalized polyhydroxyamide B,C- seco-analogues of the anticancer compound pancratistatin (PST) ( 1) is reported. Key steps include an Evans' MgCl 2-promoted anti-aldol reaction between a functionalized l-threose derivative and ( R)-(+)-oxazolidinone to stereoselectively form the C-1/C-10b bond and a regiospecific radical-mediated oxidative fragmentation of a 1,3-benzylidene. The B,C- seco compounds 25 and 26 exhibited low activity (ED 5030 microg/mL) for inducing apoptosis in human cancer cells.

Current therapy of human superficial bladder cancer includes the intravesical administration of antitumor drugs and immunomodulators. The purpose of these studies was to determine whether phospholipid liposomes that bind to human bladder cancer cells can improve the delivery of interferon alpha (IFN-alpha) to neoplastic urothelium. The antiproliferative activity of free IFN-alpha and IFN-alpha encapsulated in liposomes was assessed in vitro against the human transitional cell carcinoma line 253J. The cells were exposed to free and liposome-encapsulated IFN-alpha for short periods ranging from 30 minutes to four hours, and inhibition of cell growth was determined three days later. The production of greater than 25 percent cytostasis of 253J cells by free IFN-alpha required four hours of continuous exposure. In contrast, IFN-alpha encapsulated in liposomes produced 35 percent and 60 percent cytostasis after a 30-minute and four-hour exposure, respectively. Liposome-encapsulated IFN-alpha was also effective (50 percent cytostasis) against a subline of 253J cells selected for resistance against free IFN-alpha. Liposomes containing IFN-alpha were stable in the presence of human urine. In vivo studies in mice showed that intravesical administration of radiolabeled IFN-alpha or radiolabeled liposomes did not yield significant systemic absorption and deposition in distant organs. Collectively, these results suggest that the encapsulation of IFN-alpha within multilamellar liposomes may augment its antiproliferative activity, overcome some forms of tumor cell resistance to IFN-alpha, and prove useful for intravesical therapy of superficial bladder cancer.

Human leptomeningeal (arachnoid and pia mater) cells in culture have been demonstrated in replicated studies to express typical neuronal proteins such as neurofilament protein and neuron-specific enolase. In addition, they can express glial fibrillary acidic protein. The present study examines the possibility that neuronal and glial proteins might be present in rat and human leptomeningeal cells in situ. The neuronal proteins 160 kDa and 200 kDa neurofilaments, neuron-specific enolase and microtubule-associated protein 2 were, however, not immunolocalized in either the pia mater or arachnoid. Glial fibrillary acidic protein and galactocerebroside were also not detected, while fibronectin and vimentin immunoreactivities were robust in all layers of the leptomeninges. Together with the previously reported expression of some neuronal and astroglial markers in cultured human leptomeninges, these observations suggest that culture alters the properties of leptomeningeal cells.

The novel limonoid, astrotrichilin, has been isolated from the Madagascan Meliaceae plant Astrotrichilia asterotricha.

Once prostate cancer metastasizes to bone, conventional chemotherapy is largely ineffective. We hypothesized that inhibition of phosphorylation of the epidermal growth factor receptor (EGF-R) and platelet-derived growth factor receptor (PDGF-R) expressed on tumor cells and tumor-associated endothelial cells, which is associated with tumor progression, in combination with paclitaxel would inhibit experimental prostate cancer bone metastasis and preserve bone structure. We tested this hypothesis in nude mice, using human PC-3MM2 prostate cancer cells. PC-3MM2 cells growing adjacent to bone tissue and endothelial cells within these lesions expressed phosphorylated EGF-R and PDGF-Rα and -β on their surfaces. The percentage of positive endothelial cells and the intensity of receptor expression directly correlated with proximity to bone tissue. Oral administration of PKI166 inhibited the phosphorylation of EGF-R but not PDGF-R, whereas oral administration of STI571 inhibited the phosphorylation of PDGF-R but not EGF-R. Combination therapy using oral PKI166 and STI571 with i.p. injections of paclitaxel induced a high level of apoptosis in tumor vascular endothelial cells and tumor cells in parallel with inhibition of tumor growth in the bone, preservation of bone structure, and reduction of lymph node metastasis. Collectively, these data demonstrate that blockade of phosphorylation of EGF-R and PDGF-R coupled with administration of paclitaxel significantly suppresses experimental human prostate cancer bone metastasis.