PHARMACOLOGICAL ASPECT OF ARTEMISININ AND ARESUNATE AS POTENT ANTI MALARIAL AGENTS - OVERVIEW
Fateh AL Rahman Magbool* and Salah Eldin Omar Hussein
ABSTRACT
Artemisia annua. It comprises a new generation of antimalarial compounds that feature a nitrogenfree sesquiterpene lactone. Because artemisinin itself has physical properties such as poor bioavailability that limit its effectiveness, semi-synthetic derivatives of artemisinin, including artemether (ARM), artemotil, arteether, artenimol, and artesunate (ARST), have been developed, and are known as more effective than its parent material- artemisinin. Since 2001 the World Health Organization has recommended using artemisinin-based combination therapy (ACT) as first-line treatment for uncomplicated malaria in areas experiencing resistance to older medications. In Sudan Artesunate-SP combination is most common. Artesunate is an antimalarial agent. It is a water-soluble hemisuccinate derivative of artemisinin. Artesunate and its active metabolite dihydroartemisinin are potent blood schizonticides, active against the ring stage of the parasite. Artesunate is powerful especially in the treatment of advanced and potentially lethal cases of P. falciparum infection. It is a sesquiterpene with an unusual endoperoxide linkage structurally unrelated to other known antimalarials. ARST was developed as a pro-drug for the treatment of both uncomplicated and severe P. falciparum malaria. It is available in both enteral and parenteral formulations. It is more potent than artemisinin and is active by virtue of the endoperoxide. Their activity against strains of the parasite that had become resistant to conventional chloroquine therapy and the ability due to its lipophilic structure, to cross the blood brain barrier, it was particularly effective for the deadly cerebral malaria. Oral artesunate is hydrolyzed rapidly back to the metabolite dihydroartemisinin (DHA), which is intrinsically more active as antimalaria agent, as this metabolite is the main contributor to the overall antimalaria activity. Artemisinin and its analogs appear to be better tolerated than most antimalarials. In recent times, emergence resistant of Plasmodium sp to many of the cheap and readily available antimalarials has resulted in the continued use and dependence of artemisinins and its based combination. In Sudan, artesunate tablet is the commonest artemisinin product in the market and is available in various strengths from both local and foreign manufacturers. The quality of these antimalarials if not properly safeguarded could lead to therapeutic failure in patients and the development of drug resistance.
Keywords: Artemisinin (ARN), Artemisia annua, schizonticides.
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