Approaches, Challenges and Prospects of Antimalarial Drug Discovery from Plant Sources

Nearly 3.3 billion people globally are at risk of malaria, with 1.2 billion being at high risk. Children under 5 years of age and pregnant women in sub-Saharan Africa still account for a higher percentage of malaria-related mortalities, despite recent reports of decline in malaria mortalities in Africa. Majority of these deaths are caused by Plasmodium falciparum, a lethal malaria parasite which has developed resistance to different classes of antimalarial drugs and is responsible for complicated, severe disease. To forestall the debilitating impact of the disease and provide safe and effective alternative therapies, medicinal plants have been explored as a source of new antimalarials. The isolation of quinine and artemisinin from plants present medicinal plants as a robust source of effective antimalarials. In this chapter, we review the different approaches employed in antimalarial discovery from plants, different classes of plant antimalarial compounds and their proposed mechanisms of action. Compounds that show potential for further development based on their high efficacy and selectivity are also highlighted. Common obstacles encountered in the process of antimalarial drug discovery from plant sources are identified and prospects for the identification of new, effective antimalarial components from plant sources are also discussed

Antipyretic and analgesic activities of aqueous extract of Acacia nilotica root

This study was designed to investigate the scientific basis for the use of Acacia nilotica root extract for treatment of fever and pain in traditional medical practice. Anti-Pyretic study was carried out using Brewer\u2019s yeast suspension to induce pyrexia. The hot plate, tail immersion and acetic acid-induced writhing tests were the nociceptive models used for analgesic study. Anti-pyretic and analgesic activity of the extract was compared with acetaminophen that was used as control drug. Five groups comprising five animals per group were used for each study. Group 1 was administered 10 ml/kg body weight of distilled water, Group 2 was administered 150 mg/kg body weight of acetaminophen while groups 3, 4 and 5 were administered 100, 200 and 400 mg/kg body weight of extract respectively as single oral dose. The extract produced significant dose-dependent reduction in rectal temperature of rats at 200 and 400 mg/kg body weight. Significant analgesic activities were also observed in the hot plate, tail immersion and acetic acid induced writhing, after administration of 200 and 400 mg/kg b.w of extract which is comparable to the control drug, acetaminophen. The results from this study showed that aqueous extract of Acacia nilotica root at 200 and 400 mg/kg body weight possess significant antipyretic and analgesic activities. This provides scientific support for its traditional medical use in the treatment of fever and pain

GASTRO-PROTECTIVE EFFECT OF CROSSOPTERYX FEBRIFUGA IN WISTAR RATS.

Preparations of Crossopteryx febrifuga (Afzel.) Benth. (Rubiaceae) are widely used in Northern Nigeria in the therapeutic management of trypanosomiasis, malaria and painful inflammatory disorders. Previous studies have shown that the methanolic stem bark extract of Crossopteryx febrifuga possesses significant analgesic and anti-inflammatory properties possibly mediated via Non-selective inhibition of cyclo-oxygenase pathways. In the present study, the methanolic stem bark extract of Crossopteryx febrifuga was evaluated against ethanol- and piroxicam-induced ulceration in rats. Histopathological studies of the rat stomach tissues were also carried out in order to determine its safety profile on the gastrointestinal tract (git). The extract (25, 50 and100 mg extract/kg body weight) significantly (