Throughout medical history, plant products have been shown to be valuable sources of novel anti-cancer drugs. Examples are the VINCA: alkaloids, the taxanes, and the camptothecins, derived from the Madagscan periwinkle plant Catharantus roseus, the Pacific yew Taxus brevifolia, and the Chinese tree Camptotheca acuminata, respectively. For this reason, the South-American Office for Anti-Cancer Drug Development has implemented a large-scale project of acquisition and testing of compounds isolated from South American medicinal plants. The species are selected on the basis of a potentially useful phytochemical composition by consulting ethnopharmacological, chemosystemic, and ecological information. The collected samples are dried and first extracted with an organic solvent, then with distilled water. These crude extracts are evaluated at a concentration of 50 microg/ml for antiproliferative activity against one cell line. Extracts that significantly inhibit the growth of the cells (>/=50%) at relatively low concentrations (

A large body of evidence suggests that the abnormal phenotype of neoplastic astrocytes, including their excessive proliferation rate and high propensity to invade surrounding tissues, results from mutations in critical genes involved in key cellular events. These genetic alterations can affect cell-surface-associated receptors, elements of signaling pathways, or components of the cell cycle clock, conferring a gain or a loss of relevant metabolic functions of the cells. The understanding of such phenomena may allow the development of more efficacious forms of cancer treatment. Examples are therapies specifically directed against overexpressed epidermal growth factor receptor, hyperactive Ras, excessively stimulated Raf-1, overproduced ornithine decarboxylase, or aberrantly activated cyclindependent kinases. The applicability of some of these approaches is now being assessed in patients suffering from primary malignant central nervous system tumors that are not amenable to current therapeutic modalities. Another potentially useful therapeutic strategy against such tumors involves the inhibition of hyperactive or overexpressed protein kinase C (PKC). This strategy is justified by the decrease in cell proliferation and invasion following inhibition of the activity of this enzyme observed in preclinical glioma models. Thus, interference with PKC activity may represent a novel form of experimental cancer treatment that may simultaneously restrain the hyperproliferative state and the invasive capacity of high-grade malignant gliomas without inducing the expected toxicity of classical cytotoxic agents. Of note, the experimental use of PKC-inhibiting agents in patients with refractory high-grade malignant gliomas has indeed led to some clinical responses. The present paper reviews the current status of the biochemistry and molecular biology of PKC, as well as the possibilities for developing novel anti-PKC-based therapies for central nervous system malignancies. The

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The Republic of Suriname (South America) is located on the Guiana Shield, one of the regions with the highest biodiversity and the largest expanse of undisturbed tropical rain forest in the world. The population of almost 570,000 consists of a unique blend of ethnic groups and cultures from all continents. These include Indigenous Amerindians, the original inhabitants; Maroons, the descendants of runaway slaves who had been shipped from Africa between the seventeenth and the nineteenth century; Creoles, a generic term referring to mixed blacks and whites; the descendants from indentured workers from China, India, and Java (Indonesia) who arrived between the second half of the nineteenth and the irst half of the twentieth century; as well as immigrants from various Middle Eastern, European, Caribbean, and South American countries. All these groups have made their own speciic contribution to Suriname's traditional medicine, which has resulted in a myriad of remedies against many disorders, mainly employing a variety of plants. This chapter presents a brief history of Suriname, addresses the ethnopharmacological practices of Maroons and Creoles as well as Hindustanis and Javanese, and concludes with a few remarks on the previsions provided by the country's rich plant-based traditional medicine.

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