.................................................................................................................................................. xvii CHAPTER ONE .......................................................................................................................................... 1 1.0 INTRODUCTION AND LITERATURE REVIEW ........................................................................... 1 1.1 General introduction.......................................................................................................... 1 1.1.1 Plants as sources of medicines ......................................................................1 1.2 Literature review ............................................................................................................... 3 1.2.1 Malaria disease ...............................................................................................3 1.2.1.1 Transmission of malaria ..................................................................................... 4 1.2.1.2 Symptoms of malaria .......................................................................................... 5 1.2.1.3 International perspective of malaria................................................................... 7 1.2.1.4 Malaria control .................................................................................................... 8 1.2.2 The role of plants in development of medicines for malaria .................... 10 1.2.2.1 Annonaceae family ........................................................................................... 12 1.2.2.2 Monanthotaxis genus in Kenya ........................................................................ 14 1.2.2.3 Monanthotaxis parvifolia ssp. kenyensis ......................................................... 17 1.3 Study justification ........................................................................................................... 19 1.4 Study objectives .............................................................................................................. 19

Antiplasmodial and phytochemical investigation of monanthotaxis parvifolia (oliv.) verdc ssp. kenyensis verdc (annonaceae)

Drug resistance developed by Plasmodium falciparum doubled their rates of infection in the last two decades and encourages efforts to further explore natural materials that can be used as a new antimalarial drug. Thus, present study aims to evaluate "in vitro" antioxidant (DPPH test) and antiplasmodial activities of ethanolic and aqueous ethanolic extracts (30/70) of Benin’s Polygonum senegalense leaves. Compared with the ethanolic extract, only the hydroethanolic extract has a good anti-radical activity with an IC50 (0.18 mg/mL) similar to that of quercetin (0.1 mg/mL) which is one of references antioxidants used in this study. This activity would be due to the presence of phenolic compounds identified during the phytochemical screening of Polygonum leaves and their high presence in the aqueous ethanolic extract (81.76 mg/g against 17.83 mg/g for the ethanol extract) revealed by quantitative analysis. Both extracts investigated showed good antiplasmodial activity (IC50 50 μg/mL). The plant material studied is therefore a potential source of phenolic compounds, antimalarial and anti-radical molecules. Keywords: Polygonum senegalense, Phenolic compounds, Antiradical, Antiplasmodial.

Pascal S. Atchade

Papers

Radical Scavenging and Antiplasmodial Activity of Polygonum senegalense of Benin