Phytochemical Investigation of Fuerstia africana for Antiplasmodial, Antibacterial and Antileishmanial Compounds

Malaria is the single most important cause of ill health, death and poverty in the sub-Saharan Africa and the burden of this disease is getting even much worse mainly due to the increasing resistance of Plasmodium falciparum towards the widely available antimalarial drugs; therefore there is an urgent need for the discovery of new antimalarial agents. Two major antimalarial drugs widely used today came originally from an indigenous medical system that is quinine and artemisinin, from Peruvian and Chinese ancestral treatments respectively. Antibiotics have revolutionized medicine in many respects, and countless lives have been saved; their discovery was a turning point in human history. Regrettably, the use of these wonder drugs has been accompanied by the rapid appearance of resistant strains. Medical pundits are now warning of a return to the pre-antibiotic era; a recent database lists the existence of more than 20,000 potential resistance genes of nearly 400 different types.

Leishmaniases is another public health problem affecting approximately 12 million people in 88 countries, where 350 million people live in remote rural areas and undeserved urban areas and the drugs currently in use are very expensive, require long term treatment, display high liver and heart toxicities and develop clinical resistance after a few weeks of treatment. Thus ethno-pharmacology is a very important resource in which new therapies may be discovered. The present review is an analysis of a Kenyan medicinal plant Fuerstia africana for antimalaria antileishmanial and antibacterial therapies. 

Stem bark and leaves of Fuerstia Africana was extracted with 1:1 MeOH/ CH2Cl2. The extracts were then subjected to chromatographic separations and this led to isolation of six compounds (AOO1- AOO6).

2.56 kg of ground Fuerstia Africana stem bark was extracted with 1:1 CH2Cl2/ MeOH and 5%H2O/ MeOH to yield a dark brown extract weighing194.2g. A sample of 65g of the 1:1 CH2Cl2/ MeOH extract was subjected to column chromatography (cc) using n- hexane/ CH2Cl2/ MeOH in increasing polarity to yield a total of 114 fractions which were combined based on their analytical TLC’s into eight fractions. Crystallization yielded six pure compounds: AOO1 (15 mg), AOO2 (10 mg), AOO3 (5 mg), AOO4 (10 mg), AOO5 (10 mg) and AOO6 (5 mg). The 5%H2O/ MeOH extract was also made but not chromatographed further due to time constraint.

The structures of these compounds are being determined using NMR (1H, 13C, COSY, HMQC, and HMBC) and MS spectroscopy. Their bioassays were also being done to determine their bioactivities.

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