A new antimalarial agent; effects of extracts of Artemisia diffusa against Plasmodium berghei

Malaria is one of the most serious health problems in many parts of the world, particularly in Africa, Asia and Latin America. There are at least 300 million acute cases of malaria each year globally, resulting in more than a million deaths. Around 90% of those deaths occur in Africa; mostly in young children. Drug-resistant malaria is a major world wide public health problem. In Southeast Asia, for example, Plasmodium falciparum strains have become resistant to all of the classical antimalarias. Fortunately, these strains are still susceptible to the artemisinin derivatives. All of the artemisinin compounds contain stable endoperoxide bridges. The genus Artemisia including some Iranian species has been studied chemically and the presence of monoterpenes, sesquiterpenes, especially sesquiterpene lactones and essential oils was reported. The extract of the aerial parts of A. diffusa collected in the Province of Khorassan (Iran) afforded, in addition to several eudesmanolides, a new type of sesquiterpene lactone (Tehranolide) with an endoperoxide group that probably has the same effect as the antimalarial agent Artemisinin. We report here the antimalaria properties of a crude extract of the same species (Artemisia diffusa Krasch. ex Poljakov). The study especially examined the inhibitory effects of the extracts on developmental stages of in vivo of Plasmodium berghei in mice. Since the endoperoxide group is an essential requirement for the antimalarial activity of artemisinin, we presume the antimalarial properties of the crude extract of A. diffusa are attributed to Tehranolide. In the preliminary experiments, the toxicity of the ethanolic extract was tested, and judging from the high doses that were tolerated without significant overt mortality or signs of toxicity, it was estimated that the plant ethanolic extract is of relating low toxicity.

Tehranolide