0000000000256147
AUTHOR
Rebecca Hamm
Coumarins and Related Compounds from the Medicinal Plants of Africa
Coumarins (1-benzopyran-2-one) are chemical compounds in the benzopyrone class of organic compounds found in many plants. Coumarins possess a variety of biological properties, including antimicrobial, antiviral, antiinflammatory, antidiabetic, antioxidant, and enzyme inhibitory activity. This chapter gives an overview of the isolation, structural features, and pharmacological actions of variety of coumarins produced by the African plants. The biosynthetic pathway of coumarins is also discussed in this chapter. We identify 117 coumarins in African plants, of which 48 are new. The pharmacological activities of 54 of these coumarins are reported and documented in this chapter.
Biopiracy of natural products and good bioprospecting practice
Made available in DSpace on 2018-11-26T16:27:45Z (GMT). No. of bitstreams: 0 Previous issue date: 2016-02-15 Deutsche Forschungsgemeinschaft Background: Biopiracy mainly focuses on the use of biological resources and/or knowledge of indigenous tribes or communities without allowing them to share the revenues generated out of economic exploitation or other non-monetary incentives associated with the resource/knowledge. Methods: Based on collaborations of scientists from five continents, we have created a communication platform to discuss not only scientific topics, but also more general issues with social relevance. This platform was termed 'PhytCancer -Phytotherapy to Fight Cancer' (www.phy…
Mechanism of action of Rhodiola, salidroside, tyrosol and triandrin in isolated neuroglial cells: An interactive pathway analysis of the downstream effects using RNA microarray data
Abstract Aim The aim of this study was to identify the targets (genes, interactive signaling pathways, and molecular networks) of Rhodiola rosea extract in isolated neuroglia cells and to predict the effects of Rhodiola extract on cellular functions and diseases. In addition, the potential mechanism of action of Rhodiola rosea extract was elucidated, and the “active principle” among the three isolated constituents (salidroside, triandrin, and tyrosol) was identified. Methods Gene expression profiling was performed using the T98G human neuroglia cell line after treatment with the Rhodiola rosea SHR-5 extract and several of its individual constituents (salidroside, triandrin and tyrosol). An …
Induction of cholesterol biosynthesis by archazolid B in T24 bladder cancer cells.
Abstract Background Resistance of cancer cells towards chemotherapeutics represents a major cause of therapy failure. The objective of our study was to evaluate cellular defense strategies in response to the novel vacuolar H+-ATPase inhibitor, archazolid B. Experimental approach: The effects of archazolid B on T24 bladder carcinoma cells were investigated by combining “omics” technologies (transcriptomics (mRNA and miRNA) and proteomics). Free cholesterol distribution was determined by filipin staining using flow cytometry and fluorescence microscopy. Flow cytometry was performed for LDLR surface expression studies. Uptake of LDL cholesterol was visualized by confocal microscopy. SREBP acti…
Up-regulation of cholesterol associated genes as novel resistance mechanism in glioblastoma cells in response to archazolid B
Treatment of glioblastoma multiforme (GBM), the most common and aggressive lethal brain tumor, represents a great challenge. Despite decades of research, the survival prognosis of GBM patients is unfavorable and more effective therapeutics are sorely required. Archazolid B, a potent vacuolar H(+)-ATPase inhibitor influencing cellular pH values, is a promising new compound exerting cytotoxicity in the nanomolar range on wild-type U87MG glioblastoma cells and U87MG.∆EGFR cells transfected with a mutant epidermal growth factor receptor (EGFR) gene. Gene expression profiling using microarray technology showed that archazolid B caused drastic disturbances in cholesterol homeostasis. Cholesterol,…
Harmful and Protective Effects of Terpenoids from African Medicinal Plants
Terpenoids represent the most widespread group of natural products and can be found in all classes of living things. Many defensive compounds include sesquiterpenoids and diterpenoids from angiosperm species. Several terpenoids are biologically active and are exploited in the fight against cancer, malaria, inflammation, and a variety of infectious diseases. Nonetheless, some compounds of this group showed toxic effects causing gastrointestinal problems or central nervous system manifestations among others. Several bioactive terpenoids were identified in African medicine with numbers of them having organ-protective effects while few are known for their nonbeneficial properties for humans. In…
Synergy and Antagonism of Active Constituents of ADAPT-232 on Transcriptional Level of Metabolic Regulation of Isolated Neuroglial Cells
Gene expression profiling was performed on the human neuroglial cell line T98G after treatment with adaptogen ADAPT-232 and its constituents - extracts of Eleutherococcus senticosus root, Schisandra chinensis berry, and Rhodiola rosea root as well as several constituents individually, namely, eleutheroside E, schizandrin B, salidroside, triandrin, and tyrosol. A common feature for all tested adaptogens was their effect on G-protein-coupled receptor signaling pathways, i.e., cAMP, phospholipase C (PLC), and phosphatidylinositol signal transduction pathways. Adaptogens may reduce the cAMP level in brain cells by down-regulation of adenylate cyclase gene ADC2Y and up-regulation of phosphodiest…
Cytotoxicity of natural products and derivatives toward MCF-7 cell monolayers and cancer stem-like mammospheres
Abstract Although cancer stem-like cells (CSCs) are rare, they can enter a non-proliferative or dormant state and resist therapy. Furthermore, quiescent CSCs are responsible for metastases that can appear after curative surgical treatment of a primary tumor. Because of drug resistance of CSCs, the development of novel therapies is urgently required that specifically target CSCs. Purpose The aim of the present study was to investigate the potential of a panel of natural products and derivatives to inhibit CSC-enriched mammospheres of MCF-7 breast cancer cells. Methods CD44high/CD24low cells were identified by flow cytometry and maintained as mammospheres. As a control, we used two clinically…