Articles

Oral artemether for prevention of Schistosoma mansoni infection: randomised controlled trial

Schistosomiasis is a disabling waterborne parasitic disease that causes both acute and chronic disease. Adult worms live in different human venous systems and eggs secreted by females generate a chronic granulomatous reaction responsible for localized disease in the intestine, liver, and urogenital tract. This chapter reviews the transmission, pathophysiology, clinical presentation, diagnosis, and treatment option for all forms of schistosomiasis.

Schistosomiasis is a neglected, tropical, vector-borne, water-borne disease caused by helminth parasites of the genus Schistosoma. It is globally distributed, still reported from 78 countries, and estimated to affect over 200 million people. Schistosomes have complex life cycles, entailing snail intermediate hosts; some schistosome species have animal reservoirs, which makes public health control more challenging. Humans contract the infection following contact with freshwater contaminated with larval stages of the parasite. Morbidity is mainly caused by granulomatous reactions to the parasite's eggs trapped in organ tissues and the resulting fibrosis. Two main clinical forms exist: intestinal and urinary (or urogenital) schistosomiasis. Detection of parasite eggs in the stool and urine is the gold standard for diagnosis, although a wide range of tests and diagnostic techniques have been developed and are available. The anthelminthic praziquantel is the treatment of choice against all the species of schistosomes. Its mass administration at regular intervals to populations living in endemic areas (preventive chemotherapy) is the mainstay of WHO's strategy for public health control of schistosomiasis, with over 105 million treated in 2019. Snail control, access to water and sanitation, environmental management, health education, chemoprophylaxis and treatment of animal reservoir are complementary public health interventions. No vaccine is currently available. The new road map for neglected tropical diseases 2021–30 lists schistosomiasis among the diseases targeted for elimination as a public health problem by 2030.

From ancient times, plants have been used by our ancestors in treatment of numerous ailments. Plants used in traditional Chinese medicine (TCM), which have been cultivated and expanded for thousands of years, are well documented for a plethora of beneficial effects against a variety of diseases. The bioactive component/s responsible for the pharmacological effect has been isolated and characterized through various modern techniques, which help us in carrying out further clinical studies and then commercialize the component in the form of a drug for human well-being. Moreover, these bioactive components also act as a lead compound in new drug program. In this chapter, we describe few bioactive constituents of TCM, their isolation, biological properties, and chemical synthesis.

Phase I, II, and III comparative clinical trials on artemisinin derivatives and on the active metabolite dihydroartemisinin and various formulations of these antimalarials are described in detail.

In this work, we investigated the influence of polyvinylpyrrolidone (PVP) on the solubility of artemisinin in aqueous solution by using quantitative ¹H NMR. Experimental results demonstrate that about 4 times of incremental increase occurs on the solubility of artemisinin upon introducing PVP. In addition, dipole-dipole interaction between the ester group of artemisinin and the amide group of N-methylpyrrolidone (NMP), a model compound of PVP, is characterized by two-dimensional (2D) correlation FTIR spectroscopy with the DAOSD (Double Asynchronous Orthogonal Sample Design) approach developed in our previous work. The observation of cross peaks in a pair of 2D asynchronous spectra suggests that dipole-dipole interaction indeed occurs between the ester group of artemisinin and amide group of NMP. Moreover, the pattern of cross peaks indicates that the carbonyl band of artemisinin undergoes blue-shift while the bandwidth and absorptivity increases via interaction with NMP, and the amide band of NMP undergoes blue-shift while the absorptivity increases via interaction with artemisinin. Dipole-dipole interaction, as one of the strongest intermolecular interaction between artemisinin and excipient, may play an important role in the enhancement of the solubility of artemisinin in aqueous solution.