5308381 Ammonia extraction of gold and silver from ores and other materials: Kenneth N Han, Xinghu Meng assigned to South Dakota School of Mines & Technology

Abstract

Leishmaniasis is a vector-borne parasitic disease caused by protozoan parasites belonging to the family Trypanosomatidae and genus Leishmania. The disease prevails in 88 subtropical and tropical countries in five continents where about 350 million people live. Approximately two million incidences of new cases are recorded every year, causing high morbidity and mortality with a wide spectrum of clinical manifestations in humans. Treatment for leishmaniasis depends on pentavalent antimonials developed 50 years ago as first-line drugs, whereas a limited range of other drugs such as paromomycin, miltefosine, and amphotericin B exist to supplement them. However, potential toxicity, costs, and emergence of drug-resistant pathogens are the most serious obstacles for successful treatment of the disease in most endemic areas. This demands the development of new antileishmanial agents. In this regard, the search for new drugs from various synthetic products continues, and involves also compounds isolated from natural sources and drugs used for the treatment of other ailments (cancer, viral infections, TB, immunosuppression, etc.) in order to discover compounds with unknown chemical structures and with potential novel modes of action. Medicinal and aromatic plants are a major source of natural organic compounds which are widely used as medicine. The extensive ethnomedicinal knowledge, diversity of plant species, and the disease burden worldwide necessitates the status of natural products in treatments of leishmaniasis to be assessed. This chapter will review plant crude extracts and fractions/active principles obtained from medicinal plants which are used in or have potential for the treatment of leishmaniasis. Plant species are systematically presented by family, bioactive phytochemicals in various classes, and results obtained on specific organisms tested. Recent empirical and rationale approaches for antileishmanial drug targeting and development of novel drugs derived from natural products will be discussed.